A Novel Utility for an Old Method: The Leukocyte Adherence Inhibition Test Is an Easy Way to Detect the Immunoreactive Interference of the Collection Tube Anticoagulant on Cellular Immunoassays

The leukocyte adherence inhibition (LAI) test was designed to evaluate the presence of cellular immunoreactivity against specific antigens and is highly sensitive to analytical interference. To compare the performance of the LAI test among plasmas obtained with different anticoagulants, 36 blood samples of allergic subjects were divided into three tubes with heparin, sodium citrate, and EDTA. The adherence was assessed with the hemocytometer technique. The mean adherence of each group was compared as well as the number of tests with inappropriate adherence (<25%). Of the 36 tests, there were 4, 9, and 21 with inappropriate adherence in the groups of heparin, citrate, and EDTA, respectively. Of these last, 5 samples also did not demonstrate proper adherence with sodium citrate and 1 sample did not show proper adherence with any anticoagulant. The anticoagulant in the collection tube can elicit a specific immune response, becoming an interferent for the LAI test. In this case, there is the possibility of redoing the test using another anticoagulant. Performed with different anticoagulants, the LAI test may be used as a preanalytical tool for choosing the less immunoreactive anticoagulant for more complex immunoassays.