**2. Historical perspective of quality control in laboratories**

Walter Andrew Shewhart (March 18, 1891–March 11, 1967) was an American engineer, statistician and physicist, also called "the Father of Modern Quality Control," and he is also credited as the founder of the "Shewhart cycle" [1] (**Figure 1**). Walter Shewhart was instrumental in the introduction and development of "Process Control" in the year 1924. Prevention of the manufacture of defective products was the main aim of this method. For

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**2.1. Levey-Jennings chart**

quality control process [11].

It is a chart in which the data from a quality control are plotted and from which visually we can find out whether a particular laboratory test is working or not. The name of the chart is given after Stanley Levey and Εlmer R. Jennings who first introduced this chart in the 1950s.

Introductory Chapter: History and Scope of Quality Control in Laboratories

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When Rausch and Freier introduced that serum pools should be used in place of samples from patients, the chart of Stanley Levey and Εlmer R. Jennings became even more popular. Thus, these samples that came to be called as "standards" were ultimately known as "control samples" [6].

In 1954, E.S. Page of the University of Cambridge introduced the sequential analysis technique known as the cumulative sum control chart (CUSUM). CUSUM was devised as a method to find out changes in the techniques or quality and also the exact time as to when to take corrective actions. But the CUSUM chart was only analyzed for feasible use in the laboratory many years later. It was followed by the invention of the "Exponentially Weighted Moving Average (EWMA)" chart in 1959 by the American S.W. Roberts [7]. However, the EWMA chart was

However the use of patient results for quality control only started during 1960–1970. One of the pioneers in this field was the Japanese statistician Kaoru Ishikawa. Quality control was used for patients' tests involving hematology and biochemistry laboratories [9]. Dennis Dorsay, in 1963, was one of the pioneers who stressed the importance of erythrocyte indexes

Repeated assaying of whole blood samples from two successive days was advocated by Frank Ductra in 1966; this was to be done in place of control samples and also revolutionized the

In 1965, Michael Waid and Robert Hoffmann introduced the unique "Average of normals" (AON) method where systematic errors can be detected by the arithmetic average of normal

Quality control in hematology analyzers, called "Bull's algorithm" or "X\_B", was introduced

The introduction of "Computer simulations" brought about a big change in the issues of quality control. It was introduced by the Swedish clinical engineer Torsten Aronson, medical doctor Carl-Henric de Verdier and a physicist Torgny Groth [10, 14]. In the same year, Arthur Gottmann and Jerome Nosanchuk [13, 14] utilized the new method of comparing each patient's results with previous results, within a specified time, to detect any errors made my analyzers. It proved to be a reliable and cost-effective quality method. The distinctive feature of this method was the use of patient's results instead of control samples, and it does not make

The "delta check method" (in comparison with the previous record) and the "rate check method" in which the time elapsed between measurements were being considered and were suggested by Nosanchuk and Gottmann [15]. Usefulness of the moving average was elucidated by the Canadian clinical chemist George Cembrowski and the American clinical pathologist James

It has become so popular that nowadays that it is even used for automated analyzers.

adapted for use in medical laboratory applications much later [8].

for quality control in various hematology analyzers [10].

test results produced by biochemical analyses [12].

in 1974 by the American hematologist Brian Bull [13].

any discrimination between normal and pathological values.

**Figure 1.** Walter Andrew Shewhart (March 18, 1891–March 11, 1967) [reference: http://www.york.ac.uk/depts/maths/ histstat/people/shewhart.gif] [4].

**Figure 2.** William Edwards Deming (October 14, 1900–December 20, 1993). http://www.fda.gov/oc/initiatives/criticalpath/ stanski/stanski.html [5].

this, he also suggested and developed control charts, known as "Average Shewhart Chart" and "R Shewhart Chart or Range Shewhart Chart". W. Edwards Deming was another pioneer in this field [2–5] (**Figure 2**). He developed 14 rules, which comprised of a series of successive steps of testing. His contributions boosted Japan's rapid industrial growth in the post-war period.
