Determine the titer of isohemagglutinins (anti-A and/or anti-B) in serum; the absence of expected isohemagglutinins may suggest an immunological deficiency. This test is not recommended for the determination of immunodeficiency. Dependent upon a variety of factors, normal titers are >1:8.
Lavender-top (EDTA) tube
Gross hemolysis; bacterial or other contamination