Cord blood screening for hemoglobin abnormalities by thin layer isoelectric focusing.

Hemoglobin variants can be successfully identified in cord blood samples. The methods most commonly used include cellulose acetate (CAC) and citrate agar (CAG) electrophoresis. Recently thin layer isoelectric focusing (TLIF) has been shown to be an excellent method for identifying hemoglobin variants. To determine the applicability of TLIF for cord blood screening, we compared the results of 835 samples obtained by TLIF with that obtained by CAC, CAG, and the combination of both CAC and CAG. In 100 of these samples we detected an abnormal hemoglobin pattern using TLIF. In contrast, we detected only 80 abnormal samples by CAC, 70 by CAG, and 80 by using the combination of CAC and CAG. Due to the increased resolution provided by TLIF, we correctly diagnosed two sickle cell trait samples by TLIF that were incorrectly suspected to be homozygous for sickle cell disease by CAC and CAG. We identified 41 samples containing Bart's hemoglobin by TLIF in contrast to only 21 using CAC and 14 using CAG. The time and cost of TLIF was comparable to that using the combination of both methods. We, therefore, conclude that TLIF is the method of choice for cord blood screening.