Detection of cryoglobulins by Coulter Counter model S-Plus IV/D.

Cryoglobulins may produce interference in results from electronic particle counters. Depending on their size, cold-precipitable globulin crystals can be counted as leucocytes and/or platelets. The Coulter Counter model S-Plus IV/D permits detection of this interference and its associated spurious counts by producing a characteristic WBC histogram accompanied by a leucocyte 'flag'. Using this instrument over a 1-year period, 10 cases of cryoglobulinaemia were detected, four from patients with lymphoproliferative disease and one from a patient with autoimmune disease. The remaining five were classified as essential mixed cryoglobulinaemia. The reproducibility of this instrument anomaly permits identification of the presence of cryoglobulins.