Korean J Hematol.  2012 Mar;47(1):39-43. 10.5045/kjh.2012.47.1.39.

Usefulness of anti-PF4/heparin antibody test for intensive care unit patients with thrombocytopenia

• Park SH
• Jang S
• Shim H
• Park GB
• Park CJ
• Chi HS
• Hong SB

• KMID: 2251969
• DOI: http://doi.org/10.5045/kjh.2012.47.1.39

Abstract

BACKGROUND
It is critical to differentiate heparin-induced thrombocytopenia (HIT) from disseminated intravascular coagulation (DIC) in heparinized intensive care unit (ICU) patients with thrombocytopenia because the therapeutic approach differs based on the cause. We investigated the usefulness of PF4/heparin antibody tests in these patients.
METHODS
A total of 127 heparinized ICU patients whose platelet counts were <150x10(9)/L or reduced by >50% after 5-10 days of heparin therapy were enrolled. PF4/heparin antibodies were measured using 2 immunoassays. We assessed the probability of HIT by using Warkentin's 4T's scoring system for antibody positive patients and compared routinely performed coagulation test results between patients with and without antibodies to evaluate the ability of these tests to discriminate between HIT and DIC.
RESULTS
Positive results were obtained for 14 (11.0%) and 11 (8.7%) patients in the 2 assays. The analysis performed using the 4T's scoring system revealed that 11 of 20 (15.7%) patients with antibodies in at least 1 assay had intermediate or greater probability of HIT. Patients without antibodies had significantly higher levels of D-dimer than those with antibodies. However, there were no intergroup differences in platelet counts, PT, aPTT, fibrinogen, DIC score, and rate of overt DIC.
CONCLUSION
Seropositivity for PF4/heparin antibody was 8.7-11.0% in the patients with thrombocytopenia, and more than a half of them had an increased probability of HIT. Among the routine coagulation tests, only D-dimer was informative for differentiating HIT from DIC. PF4/heparin antibody test is useful to ensure appropriate treatment for thrombocytopenic heparinized ICU patients.

Keyword

Intensive care units; Platelet factor 4; Heparin; Antibody; Heparin-induced thrombocytopenia

MeSH Terms

Antibodies
Dacarbazine
Dietary Sucrose
Disseminated Intravascular Coagulation
Fibrin Fibrinogen Degradation Products
Fibrinogen
Heparin
Humans
Immunoassay
Critical Care
Intensive Care Units
Platelet Count
Platelet Factor 4
Thrombocytopenia
Antibodies
Dacarbazine
Dietary Sucrose
Fibrin Fibrinogen Degradation Products
Fibrinogen
Heparin
Platelet Factor 4

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