Evaluation of the Stability of Centrifuged EDTA Specimens for HIV Serology Testing

Background: Human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) is a major cause of illness and death in the United States. The diagnosis of HIV infection itself carries major personal, social and financial implications. It is therefore critical for both the patient and the physician to be certain of the diagnosis. In our laboratory, routine HIV serology testing is performed in a batched fashion, Monday through Friday. Whole blood specimens are centrifuged as soon as they are received in the laboratory and plasma is separated from the cells within 24 hrs. This separation step, however, increases the risk of specimen mislabeling and thus may misclassify patients as either HIV reactive or non-reactive. To eliminate this separation step and thus prevent the risk of specimen mislabeling, we performed a stability study by testing HIV serology on centrifuged primary, without plasma separation, at Methods: Forty-three patients were included in the study. EDTA whole blood specimens, recommended specimen type for HIV serology in our laboratory, were centrifuged, stored at 2-8°C, and tested at Results: As shown in Table-1, 46.5% (20/43) of tested specimens were reactive for HIV, while 53.5% (23/43) were non-reactive. The concordance between the Conclusion: We conclude that HIV serology testing can be performed up to 4-5 days on centrifuged primary EDTA specimens with no change in the results. Therefore, specimens received on the weekend could be tested on the following weekday without the need to separate plasma from the cells, decreasing the risk of specimen mislabeling.