Laboratory Diagnosis of Heparin-Induced Thrombocytopenia in Asian Indians as Investigated With Functional and Immunologic Methods

Abstract

Heparin-induced thrombocytopenia (HIT) was looked for in 33 Indian patients undergoing cardiovascular surgery who received unfractionated heparin (UFH). Platelet counts were performed before the initiation of UFH therapy and 5 to 16 days after administration of the therapy. A decrease in patients' platelet count >35% of the baseline value or <100,000/μL was considered to be suggestive of HIT syndrome. Heparin-induced platelet aggregation (HIPA) and enzyme-linked immunosorbent assay (ELISA) tests were performed in all the patients to detect antibodies against heparin/PF4 complex. Thrombocytopenia was found to be present in 10 (30%) patients. Of these, two patients were found to be positive as detected by HIPA and ELISA tests. These two patients were considered to have classic HIT syndrome. One of these had bleeding while the other was asymptomatic. Among the 23 non-thrombocytopenic patients and controls, HIT antibodies were not detectable by HIPA test in all but absent by ELISA in only 21 of them. Two of 23 non-thrombocytopenic patients had positive results on the ELISA test. Because the latter had negative test results on HIPA, they were considered to be false-positive results. Thus, HIT syndrome develops in approximately 6% of Indian patients treated with UFH.

Keywords

Heparin-induced thrombocytopenia Unfractionated heparin Anti-heparin-PF4 antibodies Functional assay Immunologic assay Asian-Indian subjects

References

1. King DJ , Kelton JG . Heparin-associated thrombocytopenia. Ann Intern Med 1984;100:535-535.

2. Elalamy I , Lecrubier C , Horellou MH , Conard J , Samama MM . Heparin-induced thrombocytopenia: Laboratory diagnosis and management. Ann Med 2000;32(Suppl 1):60-60.

3. Fabris F , Ahmad S , Cella G , Jeske WP , Walenga JM , Fareed J . Pathophysiology of heparin-induced thrombocytopenia: Clinical and diagnostic implications-a review. Arch Pathol Lab Med 2000;124:1657-1657.

4. Ahmad S , Untch B , Haas S , Hoppensteadt DA , Misselwitz F , Messmore HL , Walenga JM , Fareed F . Differential prevalence of anti-heparin-PF4 immunoglobulin subtypes in patients treated with clivarin and heparin: Implications in the HIT pathogenesis. Mol Cell Biochem 2003, in press.

5. Blinder MA . Heparin-induced thrombocytopenia. Lab Med Newslett 2002;8(2):1-1.

6. Warkentin TE , Kelton JG . Delayed-onset heparin-induced thrombocytopenia and thrombosis. Ann Intern Med 2001;135:502-502.

7. Warkentin TE . Heparin-induced thrombocytopenia: A 10year retrospective study. Annu Rev Med 1999;50:129-129.

8. Amiral J , Marfaing-Koka A , Poncz M , Meyer D . The biological basis of immune heparin-induced thrombocytopenia. Platelets 1998;9:77-77.

9. Chong BH . Heparin-induced thrombocytopenia. Br J Haematol 1995;89:431-431.

10.

10. Bachelot-Loza C , Saffroy R , Lasne D , Chatellier G , Aiach M , Rendu F . Importance of the FcγRIIa-Arg/His-131 polymorphism in heparin-induced thrombocytopenia diagnosis. Thromb Haemost 1998;79:523-523.

11.

11. Walenga JM , Jeske WP , Wood JJ , Ahmad S , Lewis BE , Bakhos M . Laboratory tests for heparin-induced thrombocytopenia: A multicenter study. Semin Hematol 1999; 36(Suppl 1):22-22.

12.

12. Nand S , Wong W , Yuen B , Yetter A , Schmulbach E , Gross Fisher S . Heparin-induced thrombocytopenia with thrombosis: Incidence, analysis of risk factors, and clinical outcomes in 108 consecutive patients treated at a single institution. Am J Hematol 1997;156:12-12.

13.

13. Sheridan D , Carter C , Kelton JG . A diagnostic test for heparin-induced thrombocytopenia. Blood 1986;67:27-27.

14.

14. Harenberg J , Huhle G , Giese C , Wang LC , Feuring M , Song XH , Hoffmann U . Determination of serotonin release from platelets by enzyme immunoassay in the diagnosis of heparin-induced thrombocytopenia. Br J Haematol 2000; 109:182-182.

15.

15. Osumi K , Ozeki Y , Saito S , Nagamura Y , Ito H , Kimura Y , Ogura H , Nomura S . Development and assessment of enzyme immunoassay for platelet-derived microparticles. Thromb Haemost 2001;85:326-326.

16.

16. Walenga JM , Jeske WP , Fasanella AR , Wood JJ , Ahmad S , Bakhos M . Laboratory diagnosis of heparin-induced thrombocytopenia. Clin Appl Thromb Hemost 1999; 5(Suppl 1):S21-S21.