Drug-induced immune hemolytic anemia investigation: Comparison between tube test and microcolumn agglutination (gel test) for the detection of drug-dependent antibodies in the presence of soluble drug.

OBJECTIVES

Testing for drug-dependent antibodies is traditionally performed with the tube method either with drug-treated red blood cells or with untreated red blood cells in the presence of soluble drug. Gel microcolumn agglutination method was compared to tube testing for the demonstration of drug-dependent antibodies in the presence of soluble drug.

MATERIALS AND METHODS

Patient's samples were tested in parallel by tube and gel microcolumn agglutination method with untreated and/or enzyme-treated red blood cells in the presence of soluble drug.

RESULTS

Twenty six different patient's samples were studied and thirty nine tests performed to investigate antibodies directed against fifteen different drugs. There was a good correlation between the results obtained by tube and gel method in terms of analytical sensitivity and specificity. Reactions appeared to be stronger with the gel test than seen with the conventional tube method for most of the drug antibodies investigated. Enzyme-treated cells should be used in addition to untreated cells to improve the sensitivity of the method for detecting drug-dependent antibodies especially those directed against drugs that do not bind firmly to red blood cells.

CONCLUSIONS

Gel method appeared to be sensitive, reliable, reproducible, and comparable to the conventional tube method for the detection of all the drug-dependent antibodies investigated in this study. Further studies need to be performed to evaluate gel testing for the detection of drug-dependent antibodies that only react with drug-treated red blood cells.