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Prospective diagnostic accuracy evaluation and clinical utilization of a modified assay for platelet‐associated immunoglobulin in thrombocytopenic and nonthrombocytopenic dogs
Author(s) -
Bachman Dawn E.,
Forman Marnin A.,
Hostutler Roger A.,
Corn Stephanie,
Lin JuiMing,
Kociba Gary J.
Publication year - 2015
Publication title -
veterinary clinical pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.537
H-Index - 51
eISSN - 1939-165X
pISSN - 0275-6382
DOI - 10.1111/vcp.12281
Subject(s) - antibody , medicine , platelet , immunology
Background No diagnostic tests reliably distinguish primary immune‐mediated thrombocytopenia ( pIMT ) from other causes of thrombocytopenia. Objectives The purpose of the study was to evaluate diagnostic sensitivity and specificity using modified direct and indirect platelet‐associated immunoglobulin ( PAI g) assays and reticulated platelets ( RP ) by flow cytometry for the classification of thrombocytopenic dogs and differentiating pIMT . Methods Platelets were isolated from plasma samples of thrombocytopenic dogs and nonthrombocytopenic healthy and ill dogs. For direct PAI g, they were analyzed by flow cytometry after incubation with anti‐human amylase fluorescein isothiocyanate ( FITC , negative control), anti‐canine IgG‐ FITC , anti‐canine IgM‐ FITC , and anti‐human CD 61‐conjugated fluorochrome ( AF 647). For indirect PAI g, platelets from normothrombocytic dogs were incubated with thrombocytopenic dog plasma and analyzed similar to direct PAI g. RP percentages were determined based on forward light scatter vs thiazole orange fluorescence. Results Seventy‐five thrombocytopenic dogs, 16 nonthrombocytopenic ill dogs, and 24 healthy dogs were evaluated. Diagnostic sensitivity and specificity utilizing direct IgG was 29.4% and 75.9%, respectively; when combining direct/indirect assays (IgG/IgM), it was 76.5% and 65.5%, respectively, for distinguishing pIMT . For RP , no significant difference between pIMT and sIMT was noted. RP > 8% with positive PAI g had a sensitivity of 94% and specificity of 27.6% for distinguishing pIMT . There was a significant difference in platelet concentration and CD 61% staining between control and pIMT . Conclusions The combined modified assays resulted in fair diagnostic sensitivity and specificity for the diagnosis of pIMT . The modification of the immunoglobulin assays improved diagnostic accuracy; however, a single panel to accurately classify thrombocytopenia remains elusive.