RAPID PETERMINATION OF IgM USING LATEX REAGENT IN NEONATES

Abstract

Chronic intrauterine infection commonly results in increased levels of immunoglobulin M (IgM). It is recognized that elevated levels of IgM are non-specific, but useful as a screening test. This is particularly true in infants with intrauterine growth retardation. In many hospitals IgM testing is done infrequently (e.g., twice weekly). The use of a rapid method for determination was tested for reliability by doing paired determinations of IgM by a latex method and an immunoelectrophoretic method. Samples were obtained from babies being investigated for possible bacterial or viral infection. The “positive” on the latex method is currently set at 30 mg% or more. The results were:When the false negatives (5) and false positives (3) were examined, only 1 false positive fell outside the ± 5 mg% range and was within 10 mg%. Introduction of another reagent set at 20 mg% could eliminate this error, in conjunction with the present reagent. The latex IgM method is easily performed, rapid (within 10 minutes) and inexpensive. A positive test could influence further investigatipns (e.g., viral cultures, long-bone x-rays, etc.).