PF4 ENHANCED assay for the diagnosis of heparin-induced thrombocytopenia in complex medical and surgical patients.
OBJECTIVE
To evaluate the sensitivity and specificity of the PF4 ENHANCED (GTI Diagnostics, Waukesha, WI) enzyme-linked immunosorbent assay for heparin-induced thrombocytopenia using the carbon-14 serotonin-release assay as the reference method.


METHODS
A total of 34 patients were prospectively enrolled with a variety of diagnoses and suspected heparin-induced thrombocytopenia. They were clinically scored and underwent testing with the (14)C-serotonin-release assay. Enzyme-linked immunosorbent assay and (14)C-serotonin-release assay results were also available from 21 medical and surgical patients who had previously been tested.


RESULTS
With the (14)C-serotonin-release assay as the reference method, the sensitivity and specificity of the enzyme-linked immunosorbent assay were 93% and 65%, respectively. There was only one false-negative enzyme-linked immunosorbent assay. The clinical scores were frequently misleading, largely because of difficulty excluding other causes of thrombocytopenia.


CONCLUSIONS
Because of its high sensitivity, we believe the PF4 ENHANCED enzyme-linked immunosorbent assay should be used to identify heparin-induced thrombocytopenia in patients with multiple potential causes of thrombocytopenia, although false-positive results will not be uncommon.
Shaheed
Gurvinder
G
Section of Hematology/Oncology, Department of Medicine, Washington Hospital Center, Washington, DC, USA.
Malkovska
Vera
V
Mendoza
Jose
J
Patel
Mehool
M
Rees
John
J
Wesley
Robert
R
Merryman
Paula
P
Horne
McDonald
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000009:adverse effects*; D002250:Carbon Radioisotopes; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006493:Heparin / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010978:Platelet Factor 4 / Q000032:analysis*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012701:Serotonin / Q000032:analysis; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000175:diagnosis*
D000925:Anticoagulants; D002250:Carbon Radioisotopes; D012701:Serotonin; D010978:Platelet Factor 4; D006493:Heparin