Use of 20 minute whole blood clotting time in patients of snakebite; an experience from kohat, Khyber Pakhtunkhah

Abstract

Objective: To study the diagnostic accuracy of 20-minute whole blood clotting time in hemotoxic snakebite. Study Design: Cross sectional validation study. Place and Duration of Study: Combined Military Hospital Kohat Pakistan, from Jul 2015 to Jun 2017. Methodology: Study included 52 patients who presented with the complaint of a snakebite. The data was recorded on predesigned proforma including clinical, laboratory features. All the patients were kept indoor for observation for a minimum of 72 hours from the time of presentation. Results: The study showed that males were more affected with age group between 20-50 years. Most common presenting features were local swelling 33 (71%) and pain and most common snakebite type was hemotoxic 33 (71%). The 20-minute whole blood clotting time was found to have low sensitivity (61%) and specificity (58%). A significant association was found between the dose of anti-snake venom and severity of coagulopathy (p<0.001), respiratory failure (p<0.001) and development of side effects due to anti snake venom (p<0.001). The mortality rate was 6.5% and was significantly related to age of the victims (p=0.003). The diagnostic accuracy of 20-minute whole blood clotting time was 60.25%. Conclusion: The use of 20-minute whole blood clotting time can not only be misleading but also a source of delay in administering anti snake venom given the low sensitivity and specificity and high false negative rate.