1. From: Platelet Factor 4/Heparin Antibodies in Blood Bank Donors
Figure 1 Optical density (OD) distribution of 163 repeatedly seropositive samples, grouped by level of positivity (ie, high, OD ≥1.0; intermediate, OD = 0.60–0.99; and low, OD = 0.40–0.59).
From: Platelet Factor 4/Heparin Antibodies in Blood Bank Donors
Am J Clin Pathol. 2015;134(5): doi: /AJCPG0MNR5NGKNFX
Am J Clin Pathol | © American Society for Clinical Pathology

2. From: Platelet Factor 4/Heparin Antibodies in Blood Bank Donors
Figure 2 Predominant isotype in repeatedly seropositive samples with high (n = 12, black bars) or intermediate (n = 27, white bars) positivity. In an isotype-specific enzyme-linked immunosorbent assay for platelet factor 4/heparin antibody, predominant expression of 1 isotype (IgG, IgM, or IgA) over another was defined as a relative optical density ratio of ≥2 for the respective isotypes, and a ratio <2 was considered indeterminate (see the “Materials and Methods” section).
From: Platelet Factor 4/Heparin Antibodies in Blood Bank Donors
Am J Clin Pathol. 2015;134(5): doi: /AJCPG0MNR5NGKNFX
Am J Clin Pathol | © American Society for Clinical Pathology

3. From: Platelet Factor 4/Heparin Antibodies in Blood Bank Donors
Figure 3 Comparison of optical density (OD) results from initial and repeated testing of 243 initially seropositive samples. Linear regression yielded the following results: slope = 1.00 (standard error [SE] = 0.048); intercept = −0.037 (SE = 0.028); and correlation coefficient (r) = The line of best fit is shown.
From: Platelet Factor 4/Heparin Antibodies in Blood Bank Donors
Am J Clin Pathol. 2015;134(5): doi: /AJCPG0MNR5NGKNFX
Am J Clin Pathol | © American Society for Clinical Pathology