Key Points Quality control samples are assayed on a schedule to verify that a laboratory procedure is performing correctly. Interpretation of quality control results is based on acceptance criteria that will identify bias, trend in bias, or imprecision that exceeds…
Key Points For statistical analyses, nominal variables can take on only a limited number of values (or categories), whereas continuous variables are used to report quantitative data. Independent variables are considered input (cause), and dependent variables are considered output (effect).…
Key Points Accurate differential diagnoses can be made from a systematic study of the laboratory profiles of patients in a large majority of cases. There are basically four types of anemia: iron deficiency, anemia of chronic disease, hemolytic anemia, and…
Key Points Laboratory results must undergo a two-step postanalytic review for analytic correctness (using delta checks, linearity ranges, etc.) and for clinical significance for the patient (applying critical values, reference ranges, pretest and posttest probability, etc.). Reference intervals are most…
Key Points Point-of-care testing refers to the scope of laboratory tests that are performed where patient care is delivered. This includes physician office testing as well as various hospital locations outside the laboratory, such as the emergency department, operating room,…
Key Points Laboratory testing has undergone revolutionary changes over the past decade. Typically, all routine chemistry and hematology testing is completely automated. Automated solutions are available for preanalytic, analytic, and postanalytic stages of laboratory testing. The degree of automation implemented…
Key Points Mass spectrometry can identify and quantify analytes in human fluids and tissues. Mass spectrometry is based on volatilizing samples and ionizing the analytes of interest, which can then be identified from their times of flight (TOF) or in…
Key Points Many analytic determinations made in clinical laboratories are based on measurements of radiant energy that is absorbed or transmitted. The devices used to measure absorbed or transmitted light energy are photometers and spectrophotometers. The basic components of spectrophotometers…
Key Points Errors and variables in the preanalysis stage can affect test results. Patient variables include physical activity, diet, age, sex, circadian variations, posture, stress, obesity, smoking, and medication. Strict adherence to proper technique and site selection can minimize collection…
Key Points An effective testing process requires integration of preanalytic, analytic, and postanalytic steps. An understanding of workflow is a fundamental prerequisite to any performance optimization strategy. A variety of techniques should be used to collect workflow data. These include…