Chin Med J (Taipei) 1998;61:S56.

The Importance of the Preanalytical Phase on the Accuracy of Laboratory Results

S. Narayanan, Ph.D.

Department of Pathology, New York Medical College-Metropolitan Hospital Center, New York, NY. 10029. U.S.A.

Abstract

The preanalytical phase encompasses a wide range of variables which can impact on the accuracy of laboratory results. These variables could be categorized as physiological, effect of lifestyle and therapy, and specimen collection, processing and analyte stability. Physiological variables include the effect of age, pregnancy and menstruation. Life style such as diet, consumption of caffeine, alcohol and smoking impacts on some of laboratory results. Drug therapy and radioimmuno imaging therapy using the labeled mouse monoclonal antibodies can also impact on laboratory results. The effect of posture, duration of tourniquet application, time of blood collection, anticoagulant used for specimen collection need to be standardized for assuring the quality of laboratory results. Timely separation of plasma from cells is critical to the accurate assessment of studies such as viral load measurements.

The effect of some of the preanalytical variables are also assay dependent. The impact of many of the preanalytical variables on analytical results will be illustrated with examples.

[Chin Med J (Taipei) 1998;61:S56.]