Lower hemoglobin levels in human immunodeficiency virus–infected patients with a positive direct antiglobulin test (DAT): relationship with DAT strength and clinical stages

Abstract

There are conflicting opinions regarding the effect of positive direct antiglobulin test (DAT) on hemoglobin (Hb) levels in human immunodeficiency virus-infected (HIV+) patients. A total of 166 samples from HIV+ outpatients were studied. The DAT was performed with the tube test and column agglutination technology (CAT). The DAT was positive in 18.67 percent with the tube method and 33.73 percent with the CAT. Patients with DAT-positive results showed lower Hb levels than DAT-negative patients, 12.3 g per dL versus 14.3 g per dL (p = 0.0002). The univariate logistic regression enabled us to study the phenomenon better and fit the probability of having a DAT-positive result on the basis of the Hb levels. The relationship between the CAT and the tube test when washing the red blood cells (RBC) at 4 degrees C was stronger than when washing these at room temperature (phi = 0.8156; p = 0.000). The Hb levels were significantly lower in the positive DATs of Stage C (acquired immune deficiency syndrome [AIDS]) and Stage B (symptomatic non-AIDS patients), which showed decreasing Hb values for increasing agglutination strengths (p = 0.000). Anemia was related with the DAT results (odds ratio [OR], 8.005; p = 0.000) but not to the AIDS condition (OR, 1.741; p = 0.221). Our study indicates that the DAT-positive results may be specifically related to lower Hb levels in HIV+ patients. The immunologic RBC clearance could be part of the anemic multifactorial condition in HIV+ patients.