Point-of-care derived INR does not reliably detect significant coagulopathy following Australian snakebite.
BACKGROUND
Point-of-care international normalised ratio (INR) has been suggested as a way to screen for venom-induced consumption coagulopathy following snakebite, but has not been validated for this. This study aimed to assess the diagnostic reliability of point-of-care INR for venom-induced consumption coagulopathy.


METHODS
This was a prospective study of snakebite patients recruited between January 2011 and May 2012 where a point-of-care INR was done and compared to an INR done on a laboratory coagulation analyser, as part of a quality assurance exercise. Data was obtained for each patient, including demographics, information on the snake bite, the point-of-care INR results and any laboratory derived coagulation studies. Snake identification was confirmed by expert identification or venom specific enzyme immunoassay.


RESULTS
There were 15 patients with a median age of 29 years (2 to 68 y) and 13 were male. Four of the 7 patients with venom-induced consumption coagulopathy had an abnormal point-of-care INR (3 false negatives) and 1 of the 7 non-envenomed patients had an abnormal point-of-care INR (1 false positive). The patient with a falsely elevated point-of-care INR was given antivenom prior to formal coagulation studies. The point-of-care INR was also negative in the patient with an anticoagulant coagulopathy.


CONCLUSIONS
The study shows that point-of-care INR testing devices should not be used in suspected snakebite cases in Australia to diagnose venom-induced consumption coagulopathy.
Department of Haematology, Pathology Queensland Central Laboratory, Brisbane, Queensland, Australia.
Kacey M
KM
O'Rourke
Elizabeth
E
Correlje
Cameron L
CL
Martin
Jeremy D
JD
Robertson
Geoffrey K
GK
Isbister
D000293:Adolescent; D000328:Adult; D000368:Aged; D001315:Australia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D004211:Disseminated Intravascular Coagulation / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D005260:Female; D006801:Humans; D019934:International Normalized Ratio / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D019095:Point-of-Care Systems; D012909:Snake Bites / Q000097:blood / Q000150:complications* / Q000453:epidemiology; D055815:Young Adult
Coagulopathy; Diagnostic tests; Envenomation; INR; IQR; POC; PT; Point-of-care testing; Snakebite; VICC; aPTT; activated partial thromboplastin time; international normalised ratio; interquartile range; point-of-care; prothrombin time; venom induced consumption coagulopathy