**3. Where is the possibility of error?**

Valenstein and Sirota [12] described four classifications of errors:


In a study to develop a reproducible amendment taxonomy, Meier et al. [13] described a classification in four categories: misinterpretations, misidentifications, defective specimens, and defective reports.

**1.** Misinterpretations: This category is divided into three subtypes that occurred in relation to two levels of diagnostic information. In the first subtype, the diagnostic conclusions described inaccurate information (false-positives or overcalls). In the second subtype, the pathologist failed to recognize or lost accurate information (false-negatives or undercalls). Both can occur at primary (such as changes between positive and negative status or between malignant and benign diagnosis) and secondary levels of diagnosis. The secondarylevel diagnosis refers to when the clinical context or prognostic implications depend on the pathologic diagnosis, which occurs in malignant tumors.

prior to their release (0.0 vs. 0.6/1000, *p* < 0.001), and errors related to the specimen were less reported when released after an intradepartmental review of more difficult cases (0.0 vs.

Meier [6] describes why the comparison of discrepancy rates is difficult in six different steps between the initial diagnostic event and the review event. The first is the difference in the internal and external review. In the internal review, the diagnoses under scrutiny were originally performed in the laboratory, and pathologists in other practices performed an external review. Second, the pre-sign-out review was held before a report was issued. Post-sign-out review happened after the report had been released. Third, in conference reviews, several experts discussed information about diagnosis, prognosis, and treatment of the patient to reach an agreement. Some reviews were nonconference related. Fourth, in review performed by an expert, the exam was conducted by a specialist with extensive experience and knowledge in the field. The fifth difference was blinded and nonblinded reviews. In blinded revisions, the second pathologist had the same amount of information as the first one, and sometimes a blinded reviewer was given less case-specific information. The last difference was between focused reviews in which the examiner trained the diagnosis of specific types of cases and nonfocused revisions in which the pathologist evaluated a defined fraction of cases

**1.** Depending on the scenario in which error occurred, in pre-laboratory errors (identification errors external to reference laboratory) and laboratory errors. The second form of this classification is the division of errors into pre-analytic, analytic, and post-analytic errors. This is the most common classification of errors, based on the time and place of the laboratory where they occurred: in the pre-analytical, analytical, and post-analytical phases. This division is commonly used in clinical analysis laboratories and, since they are based on

**2.** Consequences for the patient: in this case, the errors are distributed in near misses (or "close calls"), when the error is detected before causing harm to the patient. On the other hand, adverse events damage the health of a patient, such as a new biopsy or unnecessary procedure. Sentinel event is serious, which may cause permanent disability or death because of errors.

**4.** Cause of error: based on the root cause of identification errors—human factors, environ-

In a study to develop a reproducible amendment taxonomy, Meier et al. [13] described a classification in four categories: misinterpretations, misidentifications, defective specimens,

ment, equipment failure, and lastly defective rules, policies, or procedures [12].

similar work processes, they may be used to evaluate work in pathology.

**3.** Type of error: patient misidentification or specimen misidentification.

0.4/1000, *p* = 0.02) [11].

92 Quality Control in Laboratory

of various specimens or types of diagnoses.

**3. Where is the possibility of error?**

and defective reports.

Valenstein and Sirota [12] described four classifications of errors:

The third subtype is misclassifications that occur when the pathologist changes similar diagnostic categories, for example, the names of a soft tissue sarcoma, without primary diagnostic implications or secondary diagnostic information's modifying impact (the differently labeled sarcoma behaved biologically with the same degree of aggressiveness during the same treatment).


During the material reception, gross examination, and processing, there are many possibilities of error, from the exchange of samples or labels, absence or excessive cuts in the block, to cross-contamination with tissues foreign to the specimen included in the final slide. Cognitive errors, such as inadequate or incomplete macroscopic descriptions, inadequate representation of the lesion or of relevant areas necessary for its characterization, may also occur, and although some are beyond the pathologist's control, the responsibility falls directly on him, with very serious damage to the patient [8].

Morelli et al. [14] described critical points in pre-analytical steps in a pathology laboratory of a leading hospital in Lombardy, Italy. In this work, 8346 histological cases were reviewed, for which 19,774 samples were made and from which 29,956 histologies were prepared. They identified 132 errors, such as accessioning (6.5%), gross dissecting (28%), processing (1.5%), embedding (4.5%), tissue cutting and slide mounting (23%), coloring, (1.5%), labeling, and releasing (35%). Some very common errors were not detected in this work: specimen mismatching and sample contamination in gross room; mismatching or loss of specimen in embedding, loss, exhaustion, or contamination of specimen; and damage or changes of samples on the slides in cutting and slide mounting. As expected, 98.5% of the errors were due to a lack of attention, and the majority had no consequences for the patient (88%). Only 10% of the errors resulted in a delayed report to the physician. Overall, 85% of errors were detected during gross dissecting, tissue cutting or slide mounting, labeling, and releasing, and 80% of errors could be due to incorrect transcriptions of container identification, on slides, and on labels applied to the slides at the time of delivery. The quality of the slides is a prime factor for the correct diagnosis. In some cases, problems in the cutting, staining, or assembling of the slides can completely prevent an adequate diagnosis (**Figures 1** and **2**).

A study carried out in Pennsylvania, in a teaching hospital with Pathology residency training, identified 491 errors. Of these, 88% (*n* = 432) of errors were found in the pre-analytical phase, in terms of the order, identification, collection, transportation, material reception, and processing in the laboratory. The authors identified 20% (*n* = 4) of analytical and 39% of (*n* = 8) post-analytical errors [15], as shown in **Table 1**, associated with Tosuner [16] survey data.

Layfield and Anderson [17] evaluated the sample labeling errors in 29,479 cases associated with 109,354 blocks and 248,013 slides for 18 months. In identification errors, a sample was labeled with the incorrect name or identification number. In the case of samples pertaining to identification errors, a specimen was incorrectly identified as to the site of origin at the time of collection. The authors identified 75 errors; of which 55 (73%) were related to the patient's name and 18 (24%), to the anatomical site. Most of the mistakes (69%, *n* = 52) occurred in the gross examination room, 19 (25%) in the histology laboratory, and four (6%) were related to the pathologist's errors. From the errors, 73% (*n* = 55) resulted in slides assigned to noncorresponding patients. Most of the identification errors occurred in skin, esophagus, kidneys, and colon biopsies, reflecting the distribution of types of cases received in surgical pathology, with small

**Figure 2.** The presence of folding in tissue does not allow adequate observation of the morphological characteristics

Errors in Surgical Pathology Laboratory http://dx.doi.org/10.5772/intechopen.72919 95

Bixenstine et al. [18] observed 69 hospitals in 3 months and described identification defects in 2.9% of cases (1780/60,501; 95% confidence interval [CI] = 2.0–4.4%), 1.2% of containers (1018/81,656, 95% CI = 0.8–2.0%), and 2.3% of requisitions (1417/61,245, 95% CI = 1.2–4.6%). In container defects, the authors included missing specimen, container with no identified or misplaced label, absence or incorrect numeric patient identifier, absence of specimen type or source, and/or incorrect specimen type or source (or laterality). Requisition defects included the absence of requisition (or a blank requisition), date, time, name, specimen source/type,

We routinely observe the widespread use of inadequate containers, too small for the specimen, which make it difficult to withdraw. It is recommended that containers can be used to allow the material to flow without deformities. Some deformities are caused by the narrow fit of the part in the container, which prevents its proper fixation. In addition, the bottle should contain

In the cases of small biopsy, the risk of change in gross pathology is more dangerous. Sometimes histology shows evidence of suspicious exogenous tissue sample, such as tumor cells with nuclear inclusions similar to arachnoidal cells in an endometrial sample, associated with the presence of eosinophilic amorphous material morphologically similar to secretory meningioma. Some techniques can be helpful to identify mixed-up tissue specimens, such as microsat-

laterality, and/or numeric identifier (or when this information was wrong).

10–20 times the volume of the piece in a fixative solution and the specimen.

samples from endoscopy and dermatology.

(Bone marrow, H&E, 400x).

ellite PCR techniques and another [19, 20].

It is important to emphasize that the risk of loss or exchange of the specimen is critical in the pre-laboratory stage, from the moment of its collection, registration, gross description, and confection of the slide. Morelli et al. [14] described additionally in pre-laboratory phase: the presence of extraneous tissue (ET), mistaken specimen, excessive number of containers in gross dissecting, the absence of decalcification of the specimen when necessary, loss or exhaustion of specimen in tissue cutting, wrong choice for thickness section, error in identification of block to be cut, and others.

Some pre-analytical artifacts are caused by improper manipulation during the biopsy procedure. Excessive tissue trauma caused by tweezers and other surgical instruments (**Figures 3** and **4**), as well as the excessive use of electrocautery in the surgical margins, provoke artifacts that may lead to the need for a new biopsy collection.

**Figure 1.** The inappropriate cut makes it impossible to evaluate the cellularity of this biopsy (Bone marrow, H&E, 400x).

in cutting and slide mounting. As expected, 98.5% of the errors were due to a lack of attention, and the majority had no consequences for the patient (88%). Only 10% of the errors resulted in a delayed report to the physician. Overall, 85% of errors were detected during gross dissecting, tissue cutting or slide mounting, labeling, and releasing, and 80% of errors could be due to incorrect transcriptions of container identification, on slides, and on labels applied to the slides at the time of delivery. The quality of the slides is a prime factor for the correct diagnosis. In some cases, problems in the cutting, staining, or assembling of the slides can completely prevent

A study carried out in Pennsylvania, in a teaching hospital with Pathology residency training, identified 491 errors. Of these, 88% (*n* = 432) of errors were found in the pre-analytical phase, in terms of the order, identification, collection, transportation, material reception, and processing in the laboratory. The authors identified 20% (*n* = 4) of analytical and 39% of (*n* = 8) post-analytical errors [15], as shown in **Table 1**, associated with Tosuner [16]

It is important to emphasize that the risk of loss or exchange of the specimen is critical in the pre-laboratory stage, from the moment of its collection, registration, gross description, and confection of the slide. Morelli et al. [14] described additionally in pre-laboratory phase: the presence of extraneous tissue (ET), mistaken specimen, excessive number of containers in gross dissecting, the absence of decalcification of the specimen when necessary, loss or exhaustion of specimen in tissue cutting, wrong choice for thickness section, error in identifi-

Some pre-analytical artifacts are caused by improper manipulation during the biopsy procedure. Excessive tissue trauma caused by tweezers and other surgical instruments (**Figures 3** and **4**), as well as the excessive use of electrocautery in the surgical margins, provoke artifacts that may

**Figure 1.** The inappropriate cut makes it impossible to evaluate the cellularity of this biopsy (Bone marrow, H&E, 400x).

an adequate diagnosis (**Figures 1** and **2**).

cation of block to be cut, and others.

lead to the need for a new biopsy collection.

survey data.

94 Quality Control in Laboratory

**Figure 2.** The presence of folding in tissue does not allow adequate observation of the morphological characteristics (Bone marrow, H&E, 400x).

Layfield and Anderson [17] evaluated the sample labeling errors in 29,479 cases associated with 109,354 blocks and 248,013 slides for 18 months. In identification errors, a sample was labeled with the incorrect name or identification number. In the case of samples pertaining to identification errors, a specimen was incorrectly identified as to the site of origin at the time of collection. The authors identified 75 errors; of which 55 (73%) were related to the patient's name and 18 (24%), to the anatomical site. Most of the mistakes (69%, *n* = 52) occurred in the gross examination room, 19 (25%) in the histology laboratory, and four (6%) were related to the pathologist's errors. From the errors, 73% (*n* = 55) resulted in slides assigned to noncorresponding patients. Most of the identification errors occurred in skin, esophagus, kidneys, and colon biopsies, reflecting the distribution of types of cases received in surgical pathology, with small samples from endoscopy and dermatology.

Bixenstine et al. [18] observed 69 hospitals in 3 months and described identification defects in 2.9% of cases (1780/60,501; 95% confidence interval [CI] = 2.0–4.4%), 1.2% of containers (1018/81,656, 95% CI = 0.8–2.0%), and 2.3% of requisitions (1417/61,245, 95% CI = 1.2–4.6%). In container defects, the authors included missing specimen, container with no identified or misplaced label, absence or incorrect numeric patient identifier, absence of specimen type or source, and/or incorrect specimen type or source (or laterality). Requisition defects included the absence of requisition (or a blank requisition), date, time, name, specimen source/type, laterality, and/or numeric identifier (or when this information was wrong).

We routinely observe the widespread use of inadequate containers, too small for the specimen, which make it difficult to withdraw. It is recommended that containers can be used to allow the material to flow without deformities. Some deformities are caused by the narrow fit of the part in the container, which prevents its proper fixation. In addition, the bottle should contain 10–20 times the volume of the piece in a fixative solution and the specimen.

In the cases of small biopsy, the risk of change in gross pathology is more dangerous. Sometimes histology shows evidence of suspicious exogenous tissue sample, such as tumor cells with nuclear inclusions similar to arachnoidal cells in an endometrial sample, associated with the presence of eosinophilic amorphous material morphologically similar to secretory meningioma. Some techniques can be helpful to identify mixed-up tissue specimens, such as microsatellite PCR techniques and another [19, 20].

#### **Preanalytical phase1,2 : 53.3** [22] **to 88%** [21]

Deliver and registration of material

Incomplete/error in order

Order does not correspond to specimen

Sample quantity does not correspond to order

Specimen without previous marking/incorrect orientation

Incorrect anatomical site

Incomplete/inaccurate clinical information

No material in sample sent

Inappropriate packaging/fixing conditions

Specimen loss in laboratory

Integrity not preserved

Malfunction of equipment

Freezing error

Register error

#### **Analytical phase: 4** [21] **to 42.1%** [22]

Quality of the slides

Repetition of coloration

Foreign tissue in the specimen

Incorrect block identification

Interpretation errors

Delayed results

Work environment (e.g., refrigeration failure and other equipment failures)

#### **Postanalytical phase: 5.6** [21] **to 8%** [22]

Correlation errors of freezing biopsy with conventional histology

Specimen discarded during routine examination

Patients exchange

Transcription errors

Delayed results

Malfunction of laboratory information systems

1 Preanalytical phase include accessioning, gross dissecting, processing, embedding, tissue cutting, mounting, coloring, labeling and releasing slides. Some errors outside of laboratory were included in this category for didactics effects, such as identification mislabeling, loss of specimen etc., because these errors may occur in or out of laboratory. Besides that, some errors (e.g., contamination or loss of specimen) can happen in several steps inside the laboratory, since gross dissecting, embedding or tissue cutting until slide mounting.

In an accessioning, many errors can occur. For example, the use of Roman numerals for labeling sample bottles can lead to confusion when the numbers 3 and 4 (III and IV, respectively) cannot be distinguished clearly. In other cases, the extravasation of formalin or another fixation solution can clear the identification in the biopsy bottle. It becomes more critical when there are several biopsies of the same patient from different anatomic places. In some cases, only the precise information in the request form can make the pathologist think of a possible mix-up of species. Besides that, the identification in the laboratory is critical as well. Even when clearly written, the numbers for slide identification can lead to confusion, such as when the lower horizontal bar of the number 2 on the middle slide is rather short and can be mistaken as number 7 [21].

**Figure 4.** In contrast, in adequate sampling, it is possible to define the morphology of the cellular activity with perfection

**Figure 3.** The excess of crushing at the time of biopsy collection makes it impossible to properly evaluate the cellular

Errors in Surgical Pathology Laboratory http://dx.doi.org/10.5772/intechopen.72919 97

morphology in this bone marrow (Bone marrow, 100x, H&E).

(Bone marrow, 400x, H&E).

2 Another preanalytical errors describe for Morelli et al. [20] include specimen wrongly accessioned, incorrect numbering of the blocks or slides, decalcification not performed or insufficient, error in procedure temperature, specimen badly positioned, number was reported incorrectly in block or slide, error in thickness selection and loss or exhaustion of specimen in cutting, wrong coloring (manually) or error in the choice of the program (in automatic coloring).

**Table 1.** Distribution of errors according to the operating process phase and examples.

**Preanalytical phase1,2 : 53.3** [22] **to 88%** [21]

Deliver and registration of material

Order does not correspond to specimen Sample quantity does not correspond to order

Incomplete/inaccurate clinical information

Inappropriate packaging/fixing conditions

**Analytical phase: 4** [21] **to 42.1%** [22]

**Postanalytical phase: 5.6** [21] **to 8%** [22]

Specimen discarded during routine examination

Malfunction of laboratory information systems

Specimen without previous marking/incorrect orientation

Work environment (e.g., refrigeration failure and other equipment failures)

Preanalytical phase include accessioning, gross dissecting, processing, embedding, tissue cutting, mounting, coloring, labeling and releasing slides. Some errors outside of laboratory were included in this category for didactics effects, such as identification mislabeling, loss of specimen etc., because these errors may occur in or out of laboratory. Besides that, some errors (e.g., contamination or loss of specimen) can happen in several steps inside the laboratory, since gross

Another preanalytical errors describe for Morelli et al. [20] include specimen wrongly accessioned, incorrect numbering of the blocks or slides, decalcification not performed or insufficient, error in procedure temperature, specimen badly positioned, number was reported incorrectly in block or slide, error in thickness selection and loss or exhaustion of

specimen in cutting, wrong coloring (manually) or error in the choice of the program (in automatic coloring).

**Table 1.** Distribution of errors according to the operating process phase and examples.

Correlation errors of freezing biopsy with conventional histology

dissecting, embedding or tissue cutting until slide mounting.

Incomplete/error in order

96 Quality Control in Laboratory

Incorrect anatomical site

No material in sample sent

Specimen loss in laboratory Integrity not preserved Malfunction of equipment

Freezing error Register error

Quality of the slides Repetition of coloration Foreign tissue in the specimen Incorrect block identification Interpretation errors Delayed results

Patients exchange Transcription errors Delayed results

1

2

**Figure 3.** The excess of crushing at the time of biopsy collection makes it impossible to properly evaluate the cellular morphology in this bone marrow (Bone marrow, 100x, H&E).

**Figure 4.** In contrast, in adequate sampling, it is possible to define the morphology of the cellular activity with perfection (Bone marrow, 400x, H&E).

In an accessioning, many errors can occur. For example, the use of Roman numerals for labeling sample bottles can lead to confusion when the numbers 3 and 4 (III and IV, respectively) cannot be distinguished clearly. In other cases, the extravasation of formalin or another fixation solution can clear the identification in the biopsy bottle. It becomes more critical when there are several biopsies of the same patient from different anatomic places. In some cases, only the precise information in the request form can make the pathologist think of a possible mix-up of species. Besides that, the identification in the laboratory is critical as well. Even when clearly written, the numbers for slide identification can lead to confusion, such as when the lower horizontal bar of the number 2 on the middle slide is rather short and can be mistaken as number 7 [21].

In gross macroscopic examination, cutting or staining of the slides, contaminants can be a rise, often called "floaters" by laboratory staff, and most of the time it is easily recognized as such. However, contamination of patient samples by strange tissues of a similar type may represent a higher risk for misinterpretation, as in the cases in which malignant tissue fragments are found in biopsies from patients without malignancy. Carpenter [22] described that the first opportunity for this error occurs during gross examination and dissection and that some specimen types that are considered high risk for cross-contamination: esophageal biopsies, endocervical curettage specimens, and lymph nodes biopsied for metastatic malignancy. For example, contamination of an esophageal biopsy by a very small fragment of normal tissue from the small intestine or colon may lead to a false-positive diagnosis of Barrett's esophagus or, worse, when the contamination occurs by a fragment of atypical or "dysplastic" intestinal epithelium that may lead to a false interpretation of Barrett's esophagus with "dysplasia." In these cases, the productivity of the entire laboratory decreases until the pathologist discovers the source of contamination because of the longer evaluation time and the need to deepen the histological sections. This risk is foremost in laboratories that specialize in one area of the anatomic pathology (e.g., dermatopathology, gastrointestinal pathology, etc.) because most of the specimens are of a similar type, making it difficult to recognize the floaters. In a laboratory where prostate biopsies are exclusively evaluated, a little fragment of the prostate is less likely to be identified as extraneous. To reduce this risk, it is essential that a gross station stay clean and organized.

lawsuits against pathologists for diagnostic negligence at a US insurance company responsible for the insurance of 1100 pathologists. The pathology presented a low frequency of complaints (8.3% per year) and, however, with a great financial impact, measured by a number of indemnities paid per claim since many claims against pathologists resulted from the lack of diagnosis. False-negative and false-positive results for cancer accounted for 63 and 22% of claims, respectively. The highest values were related to diagnostic errors in melanomas (US\$757,146; 95% false negatives), cervicovaginal cytology (US\$686,599; 98% false negatives) and breast cancers (US\$203,192, with the same proportion of false negatives and positives). Also with respect to analytical errors, Genta [27] argued that there are external or "suprahistological" elements that interfere with the pathologist's decision which can be divided into two categories: the evidencebased ones (such as age, sex, ethnicity, and epidemiology) and the elements that arise from emotional perceptions, not rooted in objective evidence, named emotional elements, directly related to inter and intra-observer variability. Faced with a colon adenoma with high-grade dysplasia, the pathologist may believe that surgeons will interpret the presence of dysplasia as a license for an unnecessary surgical resection and feel inclined to omit such information from the report. Even the errors of pathologists, when discovered, may modify their decision-making behaviors. Biases such as visual anticipation, first impression, and preconceived judgments influence the critical decision-making processes [28]; however, to what extent such elements

Errors in Surgical Pathology Laboratory http://dx.doi.org/10.5772/intechopen.72919 99

may interfere with the pathologist's diagnostic decision-making is uncertain.

were false-positive diagnosis [30].

It is known that it is strongly recommended that pathologic diagnosis has the following characteristics: (1) accuracy and precision of report, (2) completeness of report, and (3) timeliness. The accuracy is based on scientifically validated gold standards, and it can be difficult since most of the diagnoses do not have this pattern in morphological analysis. The pathologic diagnosis depended on interpretative and subjective skills. The precision is a measurement of variation, and a minimal interobserver variation is a major goal in pathology diagnosis [29]. In a review of 344 pathology claims reported to The Doctors Company from 1995 to 1997, Troxel identified 218 claims related to surgical pathology; of these, 54% represented claims in six groups of specimen type or "high-risk" diagnostic areas, which included breast biopsy, melanoma, lymphoma, fine-needle aspiration, frozen section, and prostate biopsy. False-negative diagnosis of malignancy represented 52% of these claims, and 33% of these

In Pakistan, Ahmad et al. [31] performed a study to describe the frequency and types of error in surgical pathology reports. They found errors in 210 cases (0.37%) after analyzing 297 reports during the study conducted on 57,000 surgical pathology cases in a laboratory in Karachi in 2014. These comprised 199 formalin-fixed specimens and 11 frozen sections represented as 3.8% of a total of 2170 frozen sections. Of this—11 frozen section errors—10 were misinterpretations and the most comprised malignant diagnosis in the central nervous system. Of the 199 permanent specimens, 99 (49.7%) were misinterpretations, and the most common subspecialty/anatomic location was gastrointestinal tract (including liver, pancreas, and biliary tract) with 23.2% (*n* = 23), followed by breast (*n* = 13, 13.1%), and lungs, pleura, and mediastinum (*n* = 10, 10.1%). Some cases of misinterpretations occur as a failure to perform special stains, such as Periodic acid-Schiff stain not done in cases of the nasal polyp with fungal hyphae. Other errors occur by inadequate gross macroscopy examination when the pathologist did not select appropriate sections for microscopic examination. In these cases,

The tissue floaters can be found in histology water baths and the slide stainers. In a study performed by Platt et al. [23], extraneous tissue found in stain bath, ranging in size from two to three cells to hundreds of cells, and the principal source of contamination was represented for the first sets of xylenes and alcohols. Of 13 water baths examined, only one fragment of tissue was identified.

In the largest study of extraneous tissue (ET) in surgical pathology, with data about 275 laboratories included in Q-Probes, the quality program of CAP describes the frequency of ET in two steps: a prospective and retrospective slide review. An extraneous tissue rate of 0.6% of slides (2074/321757) in the retrospective study and 2.9% of slides (1653/57083) was detected. In 0.4 and 0.1% in the prospective and retrospective phase, respectively, the presence of ET caused difficulties in the diagnostic conclusion [24].

Deficiencies in pre-laboratory steps can occur as well. In a study with 417 laboratories in the College of American Pathologists' voluntary quality improvement program (Q-Probes) identification and accessioning deficiencies were found in 60,042 (6%) out of a total 1,004,115 cases accessioned (median deficiency rate of 3.4%). Identification of specimen was done incorrectly in 9.6, 77% errors in discrepant or missing information, and 3.6% involved specimen handling. Absence or incomplete clinical history or diagnosis on the requisition slip represented 40% of all deficiencies. A correction was done in 69% of cases involving specimen identification errors, 58% of correction was done in specimen handling errors, and 27% of cases with discrepant or missing information. Lower rates of deficiencies were identified in laboratories with lower numbers (<15,000) of accessioned cases and laboratories with a formal written plan for the detection of this type of errors [25].

Analytical errors generally have greater evidence of impact on patient care, with potentially devastating consequences for them and the responsible pathologist. Troxel [26] reviewed records of lawsuits against pathologists for diagnostic negligence at a US insurance company responsible for the insurance of 1100 pathologists. The pathology presented a low frequency of complaints (8.3% per year) and, however, with a great financial impact, measured by a number of indemnities paid per claim since many claims against pathologists resulted from the lack of diagnosis. False-negative and false-positive results for cancer accounted for 63 and 22% of claims, respectively. The highest values were related to diagnostic errors in melanomas (US\$757,146; 95% false negatives), cervicovaginal cytology (US\$686,599; 98% false negatives) and breast cancers (US\$203,192, with the same proportion of false negatives and positives). Also with respect to analytical errors, Genta [27] argued that there are external or "suprahistological" elements that interfere with the pathologist's decision which can be divided into two categories: the evidencebased ones (such as age, sex, ethnicity, and epidemiology) and the elements that arise from emotional perceptions, not rooted in objective evidence, named emotional elements, directly related to inter and intra-observer variability. Faced with a colon adenoma with high-grade dysplasia, the pathologist may believe that surgeons will interpret the presence of dysplasia as a license for an unnecessary surgical resection and feel inclined to omit such information from the report. Even the errors of pathologists, when discovered, may modify their decision-making behaviors. Biases such as visual anticipation, first impression, and preconceived judgments influence the critical decision-making processes [28]; however, to what extent such elements may interfere with the pathologist's diagnostic decision-making is uncertain.

In gross macroscopic examination, cutting or staining of the slides, contaminants can be a rise, often called "floaters" by laboratory staff, and most of the time it is easily recognized as such. However, contamination of patient samples by strange tissues of a similar type may represent a higher risk for misinterpretation, as in the cases in which malignant tissue fragments are found in biopsies from patients without malignancy. Carpenter [22] described that the first opportunity for this error occurs during gross examination and dissection and that some specimen types that are considered high risk for cross-contamination: esophageal biopsies, endocervical curettage specimens, and lymph nodes biopsied for metastatic malignancy. For example, contamination of an esophageal biopsy by a very small fragment of normal tissue from the small intestine or colon may lead to a false-positive diagnosis of Barrett's esophagus or, worse, when the contamination occurs by a fragment of atypical or "dysplastic" intestinal epithelium that may lead to a false interpretation of Barrett's esophagus with "dysplasia." In these cases, the productivity of the entire laboratory decreases until the pathologist discovers the source of contamination because of the longer evaluation time and the need to deepen the histological sections. This risk is foremost in laboratories that specialize in one area of the anatomic pathology (e.g., dermatopathology, gastrointestinal pathology, etc.) because most of the specimens are of a similar type, making it difficult to recognize the floaters. In a laboratory where prostate biopsies are exclusively evaluated, a little fragment of the prostate is less likely to be identified as extraneous. To reduce this risk, it is essential that a gross station stay clean and organized. The tissue floaters can be found in histology water baths and the slide stainers. In a study performed by Platt et al. [23], extraneous tissue found in stain bath, ranging in size from two to three cells to hundreds of cells, and the principal source of contamination was represented for the first sets of xylenes and alcohols. Of 13 water baths examined, only one fragment of

In the largest study of extraneous tissue (ET) in surgical pathology, with data about 275 laboratories included in Q-Probes, the quality program of CAP describes the frequency of ET in two steps: a prospective and retrospective slide review. An extraneous tissue rate of 0.6% of slides (2074/321757) in the retrospective study and 2.9% of slides (1653/57083) was detected. In 0.4 and 0.1% in the prospective and retrospective phase, respectively, the presence of ET

Deficiencies in pre-laboratory steps can occur as well. In a study with 417 laboratories in the College of American Pathologists' voluntary quality improvement program (Q-Probes) identification and accessioning deficiencies were found in 60,042 (6%) out of a total 1,004,115 cases accessioned (median deficiency rate of 3.4%). Identification of specimen was done incorrectly in 9.6, 77% errors in discrepant or missing information, and 3.6% involved specimen handling. Absence or incomplete clinical history or diagnosis on the requisition slip represented 40% of all deficiencies. A correction was done in 69% of cases involving specimen identification errors, 58% of correction was done in specimen handling errors, and 27% of cases with discrepant or missing information. Lower rates of deficiencies were identified in laboratories with lower numbers (<15,000) of accessioned cases and laboratories with a formal written

Analytical errors generally have greater evidence of impact on patient care, with potentially devastating consequences for them and the responsible pathologist. Troxel [26] reviewed records of

tissue was identified.

98 Quality Control in Laboratory

caused difficulties in the diagnostic conclusion [24].

plan for the detection of this type of errors [25].

It is known that it is strongly recommended that pathologic diagnosis has the following characteristics: (1) accuracy and precision of report, (2) completeness of report, and (3) timeliness. The accuracy is based on scientifically validated gold standards, and it can be difficult since most of the diagnoses do not have this pattern in morphological analysis. The pathologic diagnosis depended on interpretative and subjective skills. The precision is a measurement of variation, and a minimal interobserver variation is a major goal in pathology diagnosis [29]. In a review of 344 pathology claims reported to The Doctors Company from 1995 to 1997, Troxel identified 218 claims related to surgical pathology; of these, 54% represented claims in six groups of specimen type or "high-risk" diagnostic areas, which included breast biopsy, melanoma, lymphoma, fine-needle aspiration, frozen section, and prostate biopsy. False-negative diagnosis of malignancy represented 52% of these claims, and 33% of these were false-positive diagnosis [30].

In Pakistan, Ahmad et al. [31] performed a study to describe the frequency and types of error in surgical pathology reports. They found errors in 210 cases (0.37%) after analyzing 297 reports during the study conducted on 57,000 surgical pathology cases in a laboratory in Karachi in 2014. These comprised 199 formalin-fixed specimens and 11 frozen sections represented as 3.8% of a total of 2170 frozen sections. Of this—11 frozen section errors—10 were misinterpretations and the most comprised malignant diagnosis in the central nervous system. Of the 199 permanent specimens, 99 (49.7%) were misinterpretations, and the most common subspecialty/anatomic location was gastrointestinal tract (including liver, pancreas, and biliary tract) with 23.2% (*n* = 23), followed by breast (*n* = 13, 13.1%), and lungs, pleura, and mediastinum (*n* = 10, 10.1%). Some cases of misinterpretations occur as a failure to perform special stains, such as Periodic acid-Schiff stain not done in cases of the nasal polyp with fungal hyphae. Other errors occur by inadequate gross macroscopy examination when the pathologist did not select appropriate sections for microscopic examination. In these cases, lymph node compromised by cancer, a polyp in the gallbladder, and breast carcinomas are not described in the first macroscopic description. These errors delay delivery results because they require a new specimen exam.

**4. Looking for solutions**

diagram (**Figure 5**).

**Figure 5.** Risk assessment using a fishbone diagram.

Perkins [36] considers that the disclosure of errors in pathology is complicated by factors intrinsic to the specialty. The first barrier, as already mentioned, is the definition of error. Another concern is that the patient does not understand the nature of the error or even that the clinician is unable to explain it adequately to the patient. Even more complex is the situation that involves the discovery of the error of another individual: when the pathologist or the head of the laboratory discovers an error of a technician/ pathologist in their laboratory or external laboratories, or even when the pathologist discovers an error of a clinician from the same organization. Therefore, when disclosing an error, the pathologist must consider the potential impact on their professional relationships. It is difficult sometimes to define an error because there exists a great variability in definitions used in the literature. The most commonly utilized is a classification in pre-analytical, analytical, and post-analytical phases, but we note that the errors can overlap between these categories. For example, change of specimen can occur in pre-analytical and analytical phase. Incorrectly described laterality or anatomic sites may occur in any step at the laboratory. Because of that, the comparison of studies in literature can be difficult, as the authors used different definitions in their studies. We described a risk assessment of laboratory errors in surgical pathology in a fishbone

Errors in Surgical Pathology Laboratory http://dx.doi.org/10.5772/intechopen.72919 101

One factor conferred to the increase in the number of medical errors is the excessive decentralization of patient care. Since the patient may have several professionals working in different contexts and none with access to the complete information, the physician would work in a situation of greater susceptibility to error [1]. The lack of complete information is critical in pathology, where many cases depend on correct, clear, and complete clinical information for adequate clinical-pathological correlation. In some cases, radiological or laboratory correlation is required. In soft tissue and bone neoplasms, it is important that the pathologist

Delays in the report release may be considered as an error in the post-analytical [15] or analytical phase [16], and the turn-around time (TAT) should be used as an important quality measure in laboratories [32]. It is not uncommon for the pathologist to miss the perception that there is a patient waiting for his results; therefore, the cases should not remain for longer than necessary on the pathologist's desk [33]. Delays in TAT may be considered during the pre-analysis as delays in reception, gross examination, and material processing; during the analysis (in the diagnostic interpretation of the pathologist) or after the analysis, as the delay in typing and release of the reports to the patient. In a study performed with 713 cases of surgical pathology, 551 (77%) were released in 2 days and 162 (23%) in 3 days or more. From these, the majority of these cases were found to be pertaining to lungs, gastrointestinal tract, breasts, and samples of the genitourinary tract. Diagnosis of malignancy (including staging), consultations with other pathologists, freezing, and immunohistochemical analysis were associated with increased TAT in univariate analysis. In the multivariate analysis, the consultation with other pathologists, the diagnosis of malignancy, the use of immunohistochemistry, and the number of slides evaluated (11.3 when TAT > 2 days and 4.8 when TAT ≤ 2 days) remain as significantly associated with increased TAT. Despite CAP recommendation of an analytical response time of 2 days or less for most routine cases, the authors conclude that cancer care institutions should have a TAT longer than other services [34].

In post-analytical phase, errors include typographical errors, and in some cases, it can lead to catastrophic consequences, when the expression "cancer is present" instead of "cancer is not present." Another error in this phase included erroneous or missing non-diagnostic information, computer formatting, or transmission [29]. Besides that, some expressions can lead to confusing interpretations. It is broadly used in some expressions or phrases to communicate varying degrees of diagnostic certainty, for example, "cannot rule out," "consistent with," "highly suspicious," "favor," "indefinite for," "suggestive of," and "worrisome for." Lindley, Gillies, and Hassell evaluated 1500 surgical pathology reports and found 35% of these expressions, with wide variation in the percentage of certainty clinicians assigned to the phrases studied. The most commonly used phrases were "consistent with" (50%) and "suggestive of" (39%). The authors believe that the reasons for use for this expression may include contradictory or low probability staining results, inconsistency in clinical data, uncertain criteria in the medical literature, quantity of sample or abnormality, and possibly a concern with medicolegal consequences for an over- or under-diagnosis.

Nakhleh and Zarbo describe the amended reports from 359 laboratories, 96% of the USA, participants in the 1996 Q-Probes quality improvement program of the College of American Pathologists. A total of 3147 amended reports from 1,667,547 surgical pathology specimens accessioned in the study. They describe a median of amended reports was 1.5/1000 cases; of these, 19.2% were issued to correct patient identification errors, 38.7% to change the originally issued final diagnosis, 15.6% to change a preliminary written diagnosis, and 26.5% to change clinically significant information other than the diagnosis. The error detection was most commonly precipitated for a request from a clinician to review a case (20.5%) [35].
