The utility of pre-test clinical scoring for clinical diagnosis of heparin-induced thrombocytopenia in cardiac surgery patients of a tertiary care centre in north India.
BACKGROUND
Heparin-induced thrombocytopenia (HIT) should be diagnosed clinically as well as by laboratory assays for timely recognition, prevention and management of complications.


OBJECTIVE
To evaluate the clinical utility of pre-test clinical scoring system in combination with two immunoassays for the diagnosis of HIT in cardiac surgery patients.


METHODS
A total of 100 consecutive patients undergoing cardiac surgery were studied. Pre-test clinical scoring was carried out in patients with thrombocytopenia and further tested by two immunoassays, i.e., Heparin platelet factor 4 (H-PF4) enzyme-linked immunosorbent assay (ELISA) and particle gel immunoassay (PaGIA).


RESULTS
Of the 100 patients studied, 42 patients developed thrombocytopenia post-operatively. On pre-test clinical scoring, low T-score was observed in 6 patients, intermediate in 28 and high score in 8 patients, whereas 19 patients (45.2%) were positive by H-PF4 ELISA and 10 (23.8%) by PaGIA for H-PF4 antibody. The difference in the incidence of clinically significant HIT antibodies in the three categories was statistically significant. A good correlation was also observed with ELISA optical density, T-scoring and PaGIA.


CONCLUSIONS
Pre-test clinical scoring correlates well with the development of H-PF4 antibodies which are incriminated in the causation of thrombotic complications in patients with HIT. We also propose a protocol for diagnosing patients with clinical suspicion of HIT using pre-test clinical scoring and immunoassay.
Department of Transfusion Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow 226014, India. deepti.vij@gmail.com
D
D
Sachan
N
N
Gupta
P
P
Agarwal
R
R
Chaudhary
D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects*; D006348:Cardiac Surgical Procedures; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006493:Heparin / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D007194:India; D051741:Kruppel-Like Transcription Factors / Q000097:blood; D008297:Male; D011183:Postoperative Complications / Q000097:blood / Q000139:chemically induced* / Q000175:diagnosis*; D012097:Repressor Proteins / Q000097:blood; D013921:Thrombocytopenia / Q000097:blood / Q000139:chemically induced* / Q000175:diagnosis*
D000925:Anticoagulants; D051741:Kruppel-Like Transcription Factors; D012097:Repressor Proteins; C115768:ZNF85 protein, human; D006493:Heparin