Platelet factor 4/heparin antibodies in blood bank donors.
Platelet factor 4 (PF4)/heparin antibody, typically associated with heparin therapy, is reported in some heparin-naive people. Seroprevalence in the general population, however, remains unclear. We prospectively evaluated PF4/heparin antibody in approximately 4,000 blood bank donors using a commercial enzyme-linked immunosorbent assay for initial and then repeated (confirmatory) testing. Antibody was detected initially in 249 (6.6%; 95% confidence interval [CI], 5.8%-7.4%) of 3,795 donors and repeatedly in 163 (4.3%; 95% CI, 3.7%-5.0%) of 3,789 evaluable donors. "Unconfirmed" positives were mostly (93%) low positives (optical density [OD] = 0.40-0.59). Of 163 repeatedly positive samples, 116 (71.2%) were low positives, and 124 (76.1%) exhibited heparin-dependent binding. Predominant isotypes of intermediate to high seropositive samples (OD >0.6) were IgG (20/39 [51%]), IgM (9/39 [23%]), and indeterminate (10/39 [26%]). The marked background seroprevalence of PF4/heparin antibody (4.3%-6.6%) with the preponderance of low (and frequently nonreproducible) positives in blood donors suggests the need for further assay calibration, categorization of antibody level, and studies evaluating clinical relevance of "naturally occurring" PF4/heparin antibodies.
Hursting
Marcie J
MJ
Duke University Health System, Box 3486, Room 304 Sands Bldg, Durham, NC 27710, USA.
Pai
Poulomi J
PJ
McCracken
Julianna E
JE
Hwang
Fred
F
Suvarna
Shayela
S
Lokhnygina
Yuliya
Y
Bandarenko
Nicholas
N
Arepally
Gowthami M
GM
D000906:Antibodies / Q000097:blood / Q000276:immunology*; D001782:Blood Donors; D004797:Enzyme-Linked Immunosorbent Assay; D006493:Heparin / Q000276:immunology*; D006801:Humans; D016014:Linear Models; D010978:Platelet Factor 4 / Q000276:immunology*; D016036:Seroepidemiologic Studies
D000906:Antibodies; D010978:Platelet Factor 4; D006493:Heparin