Analysis of reasons for biological specimens rejection at a university hospital clinical laboratory

Abstract

Clinical chemistry is the area of laboratory medicine with the largest volume of tests, and it accounts for the majority of clinical decisions impacted by laboratory results. Although the frequency of errors in clinical chemistry has been minimized by automation and high accuracy of analytical instrumentation, contemporary assay technology, and strict quality management programs, occasional results are inconsistent with the clinical situation, indicating possible erroneous test results. In this chapter, the most frequent sources of inaccurate results in commonly ordered small molecule analytes, including creatinine, urea, ammonia, uric acid, glucose, electrolytes, blood gases, lactate, bilirubin, and lipid profiles, are discussed. Pre-analytical causes of variation, including physiologic and pathologic conditions, patient preparation, sample collection, and specimen processing, are also addressed. Common assay methodologies are discussed, highlighting common sources of interferences and analytical errors.