Abstract:
Venom-induced consumption coagulopathy is the most important systemic effect of snake
envenoming. Coagulation tests are helpful to accurately and promptly diagnose venom-induced
consumption coagulopathy and administer antivenom, which is the only specific treatment available.
However, bedside clotting tests play a major role in diagnosing coagulopathy in low-income settings,
where the majority of snakebites occur. We conducted a literature search in MEDLINE® from 1946 to
30 November 2019, looking for research articles describing clinical studies on bedside coagulation
tests in snakebite patients. Out of 442 articles identified, 147 articles describing bedside clotting
assays were included in the review. Three main bedside clotting tests were identified, namely the
Lee–White clotting test, 20-min whole blood clotting time and venous clotting time. Although the
original Lee–White clotting test has never been validated for snake envenoming, a recently validated
version has been used in some South American countries. The 20-min whole blood clotting time
test is the most commonly used test in a wide range of settings and for taxonomically diverse snake
species. Venous clotting time is almost exclusively used in Thailand. Many validation studies have
methodological limitations, including small sample size, lack of case-authentication, the inclusion of
a heterogeneous mix of snakebites and inappropriate uses of gold standard tests. The observation
times for bedside clotting tests were arbitrary, without proper scientific justification. Future research
needs to focus on improving the existing 20-min whole blood clotting test, and also on looking for
alternative bedside coagulation tests which are cheap, reliable and quicker.
Keywords: clotting test; bedside; snakebite; envenoming; venom-induced consumption coagulopathy
Key Contribution: This review shows the different bedside coagulation tests in diagnosing snake
venom-induced consumption coagulopathy and the limited information on their validity. We highlight
the significance of validating current bedside clotting tests in different clinical settings and emphasize
the importance of reliable, low-cost and simple alternative tests.
