Rapid detection of plasma glycocalicin by a latex agglutination test. A useful adjunct in the differential diagnosis of thrombocytopenia.

To aid in the rapid differential diagnosis of thrombocytopenia, the authors developed a latex agglutination test for glycocalicin, a proteolytic fragment of platelet membrane glycoprotein Ib. Plasma glycocalicin determinations were performed for 34 patients with thrombocytopenia. Plasma samples from four patients with aplastic anemia and ten patients with myelodysplastic syndromes, all with glycocalicin levels less than 0.6 mg/L by an enzyme-linked immunosorbent assay, all had negative results by the latex test. In contrast, positive latex agglutination titers were obtained for all 12 patients with idiopathic thrombocytopenic purpura. Eight patients with liver cirrhosis and splenomegaly had elevated levels of plasma glycocalicin, and all of their plasma samples produced agglutination. This latex agglutination test for glycocalicin allows a rapid discrimination of thrombocytopenia caused by impaired platelet production from that caused by increased platelet destruction; thus, it is suitable for use as a screening test in a routine clinical laboratory.