Differences in the clinical course of heparin induced thrombocytopenia before and after the availability of HIT IgG class testing.
BACKGROUND
To determine whether the HIT IgG class platelet factor 4 (PF4) enzyme immunoabsorbant assay (EIA) influenced the duration of parenteral direct thrombin inhibitor (pDTI) therapy or bleeding risk in patients started on pDTI for a presumed diagnosis of HIT.


METHODS
187 patients started on pDTI for presumed HIT were assessed in two time periods before (period 1, n=88 patients) and after the introduction of an IgG-specific assay (period 2, n=99 patients).


RESULTS
Patients in period 2 were treated with pDTI therapy for a median of 5 days less (p<0.0001) however the incidence of Grade III and IV bleeding episodes was not different. Bleeding was observed to occur early during the hospital course at a median of 2-3 days after initiation of the pDTI. The average pDTI drug acquisition cost was markedly decreased in period 2 when compared to period 1 (p<0.0001).


CONCLUSIONS
Implementation of the IgG class HIT EIA resulted in a decrease in the number of days on a pDTI and a decrease in the average pDTI acquisition cost per patient without an observed change in serious bleeding events.
Division of Hematology/Oncology, Rhode Island Hospital/The Miriam Hospital, Providence, RI, USA. Electronic address: jreagan@lifespan.org.
John L
JL
Reagan
Division of Hematology/Oncology, Rhode Island Hospital/The Miriam Hospital, Providence, RI, USA.
Randall R
RR
Ingham
Division of Hematologic Malignancies, H. Lee Moffitt Cancer Center and Research Institute and the University of South Florida, Tampa, FL, USA.
Samir
S
Dalia
Division of Hematology/Oncology, Rhode Island Hospital/The Miriam Hospital, Providence, RI, USA.
James N
JN
Butera
Division of Transfusion Medicine, Rhode Island Hospital/The Miriam Hospital, Providence, RI, USA.
Joseph D
JD
Sweeney
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006493:Heparin / Q000009:adverse effects*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000175:diagnosis*; D055815:Young Adult
D007074:Immunoglobulin G; D006493:Heparin
Bleeding risk; Heparin Induced Thrombocytopenia; IgG EIA; Overdiagnosis