5. Evaluation of performance of urinary iodine laboratories

Throughout a time-frame, there is need for an evaluation to be done on our urinary iodine laboratory performance. The UIMM had been validated in the year 2006. Since then, all Urinary Iodine laboratories in the country had started using the method. In the year 2008, the National IDD Survey had been carried out [17] and the urinary iodine assays was performed on the respondent samples with inclusion of IQC samples and EQA samples in every assay. The EQA samples were provided by the Institute for Clinical Pathology & Medical Research (ICPMR), Australia. Thus, with the available data, an evaluation on our laboratory performance was performed using the EQA sample results by applying the Six Sigma quality metrics [10]. The higher the sigma metrics the better, and Sigma-6 is the best, depicting very little error or errorless achievements. A method decision chart [11] was plotted for all laboratories (it was four laboratories at that time) and the achievement for every Low, Medium and High controls were determined. The method validation results were also plotted on the chart. There were two plots, i.e. one is set by The Urinary Iodine Quality Program (TUIQP) under ICPMR (Figure 8) and the other one is following the limit set by Ensuring Quality in Urinary Iodine Program (EQUIP) (Figure 9) under CDC. However, the latter EQA program had been halted

and the former EQA program is the only existing program providing services to various urinary iodine laboratories worldwide. Since urinary iodine is easily evaporated and UIMM uses digested sample of only 30 μl out of 1250 μl of total volume, high %CV is usually high in the lower concentration range of the standard curve. EQUIP which set stricter %CV limit, leads

test method group and against other test method groups. Participation in the EQA program

There are various methods which are under the External Quality Assurance Program, i.e. Sandell-Kolthoff method consists of three different assays: (1) done in tubes, digestion with chloric acid; (2) done in tubes, digestion with ammonium persulfate; (3) done in microtiter plate, digestion with ammonium persulfate. There are other methods such as using the autoanalyzer using dry ashing of urine in potassium carbonate. However, the method with highest sensitivity is the inductively-coupled plasma-mass-spectrometry (ICPMS) but small/

CDC's Ensuring the Quality of Urinary Iodine Procedures (EQUIP) program from the Centre for Disease Control and Prevention (CDC), Atlanta, U. S. A. is worldwide. To date, more than 84 iodine laboratories from more than 50 countries have participated. Our laboratory has

If any urinary iodine laboratories are interested to participate in the EQA program, please visit CDC's website. Application form should be completed and e-mail or fax it to CDC, and a confirmation e-mail will be received within 72 hours. The laboratory will then be enrolled immediately upon receipt of the form and will receive a set of EQA samples every February,

What each laboratory should do is to treat the EQA samples like normal respondent samples and run the EQA samples in duplicates in three assays on different days. Report of the results should be submitted before the deadline within 1 month after receipt of

Throughout a time-frame, there is need for an evaluation to be done on our urinary iodine laboratory performance. The UIMM had been validated in the year 2006. Since then, all Urinary Iodine laboratories in the country had started using the method. In the year 2008, the National IDD Survey had been carried out [17] and the urinary iodine assays was performed on the respondent samples with inclusion of IQC samples and EQA samples in every assay. The EQA samples were provided by the Institute for Clinical Pathology & Medical Research (ICPMR), Australia. Thus, with the available data, an evaluation on our laboratory performance was performed using the EQA sample results by applying the Six Sigma quality metrics [10]. The higher the sigma metrics the better, and Sigma-6 is the best, depicting very little error or errorless achievements. A method decision chart [11] was plotted for all laboratories (it was four laboratories at that time) and the achievement for every Low, Medium and High controls were determined. The method validation results were also plotted on the chart. There were two plots, i.e. one is set by The Urinary Iodine Quality Program (TUIQP) under ICPMR (Figure 8) and the other one is following the limit set by Ensuring Quality in Urinary Iodine Program (EQUIP) (Figure 9) under CDC. However, the latter EQA program had been halted

increases confidence of laboratory personnel in performing the analysis.

medium scale laboratories may not afford to purchase the instrument.

5. Evaluation of performance of urinary iodine laboratories

participated since the year 2010 until present.

June and October each year.

82 Quality Control in Laboratory

samples.

Figure 8. Urinary iodine micromethod's normalized method decision chart against The Urinary Iodine Quality Program (TUIQP) TEas based on the 2008 National IDD Survey EQA results (Lab A [n = 20], Lab B [n = 18], Lab C [n = 12], and Lab D [n = 6]) and the 2006 method validation study (MV). L indicates low control, M-L indicates medium-low control, M-H indicates medium-high control, and H indicates high control, according to urinary iodine ranges in Table 1 of reference [10] as reported in Hussain et al. [10] (image reproduced with permission of the rights holder, Annals of Laboratory Medicine).

Figure 9. Urinary iodine micromethod's normalized method decision chart based on the 2008 National IDD Survey EQA results (Lab A [n = 20], Lab B [n = 18], Lab C [n = 12], and Lab D [n = 6]) and against EQUIP TEas. L indicates low control, M-H indicates medium-high control, and H indicates high control, according to urinary iodine ranges in Table 1 of reference [10] as reported in Hussain et al. [10] (image reproduced with permission of the rights holder, Annals of Laboratory Medicine).

to lower sigma metrics for the Low control (Figure 9). High control is easier to pass the %CV limit set by both EQA providers (Figures 8 and 9).

6.1.2. Weighing of arsenic

a. one is empty

2. Prepare two 100 ml beakers:

beaker to the work bench.

• Do not drain the reagents in the sinks

6.1.3. Other safety precautions

6.2. Waste management

b. one is filled with 20 ml dH20 3. Weigh the chemical in the empty beaker

4. Take out the beaker from the weighing scale

1. It is a must to wear R95 or N95 mask while weighing arsenic substances as it is highly toxic

Understanding Quality Control with Urinary Iodine Estimation

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5. Pour the water from the second beaker into the first beaker by letting the water flow slowly into the first beaker. This will avoid the chemical from floating into air when transferring the

• Arsenic is highly toxic. Limit of arsenic that can be drained through the laboratory sinks with permit is 0.003 mg/l [18]. Thus, all urinary iodine assay waste should be poured into

appropriate waste containers before the glassware is soaked and washed

• Name of waste and category of waste should be written and printed on the label

• Date of the first time the waste is accumulated and date of the last time the waste is

• A void space in the waste container of approximately 10% should be allowed for expansion • Waste should be stored in closed containers, placed in a corrosive-proof basin as second-

• Waste containers for urinary iodine should be placed in the same room but not mixed

• Avoid from putting unbalanced reaction mixture in one waste bottle; this may lead to

• Each reagent waste ought to be placed in individual waste bottle, labeled and dated

• Send the waste for disposal properly as discussed in Section 6.2.

• Labels on the waste containers should be legible and clear

accumulated should be written on the waste label

accumulation of gas and the waste bottle may explode

ary containment against spillage

with wastes from other analysis

• Aware of toxicity of reagents.

and can affect pulmonary system if inhaled accidentally.

Before participating in the EQA program, another way to evaluate the nation's urinary iodine laboratories was through inter-laboratory comparison. Some analyzed respondent samples were chosen from a wide range of urinary iodine concentrations and the same samples were analyzed again by another urinary iodine laboratory by using the same method. The results were compared between the laboratories and biases were determined. Any discrepancies were then discussed and trouble-shooting to problems was carried out.
