Study Comparing Modified Lee White Clotting Time Against Twenty Minute Whole Blood Clotting Test in Snakebite Victims

Study Overview
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Brief Summary
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20 minute Whole Blood Clotting Test(20'WBCT) recommended by World Health Organisation guidelines is probably the most routinely employed bed side screening tool in the country. The Modified Lee and White (MLW) method gives a value which when performed serially gives a trend in clotting time which the investigators hypothesise to be a better tool in serially assessing the victim compared to the 20'WBCT. The investigators propose that delayed reading of both MLW and 20'WBCT to check for clot stability at 30 minutes also provides added information in management of snake bite victims.

Detailed Description
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Envenomation by snakes is common in India. Hematotoxic bites cause the highest morbidity and mortality in Kerala, a state in the south of India. 20 minute Whole Blood Clotting Test(20'WBCT) recommended by World Health Organisation guidelines is probably the most routinely employed bed side screening tool in the country. It is the tool of choice due to its cost effectiveness in low and middle income countries (LMIC). The reliability of 20'WBCT is questionable with respect to not just its rapidity but also its reliability. There is no standardisation for the test and procedure. Modified Lee White (MLW) Method for coagulation is a cheap bed side test used as part of the standard treatment protocol of snake bite victims. The MLW method gives a value which when performed serially gives a trend in clotting time which the investigators hypothesise to be a better tool in serially assessing the victim compared to the World Health Organisation recommended 20'WBCT. The investigators also propose that delayed reading of both MLW and 20'WBCT to check for clot stability also provides added information in management of snake bite victims. The bed side coagulation test done, forms the trigger to commence antivenom in snake bite victims with hematotoxicity in resource limited settings. Lee White (MLW) Method for coagulation is a test that has been employed for decades to assess coagulation in Jubilee Mission Hospital, Medical College and Research Institute in Thrissur for snake bite victims. It is a cheap bed side test used as part of the standard treatment protocol of snake bite victims. The MLW method gives a value which when performed serially gives a trend in clotting time which the investigators hypothesise to be a better tool in serially assessing the victim compared to the World Health Organisation recommended 20'WBCT. The investigators also propose that delayed reading of both MLW and 20'WBCT to check for clot stability or 'clot lysis' also provides added information in management of snake bite victims.

Official Title
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Comparing Modified Lee White Method Against 20 Minute Whole Blood Clotting Test as a Bedside Coagulation Test in Snake Envenomation Victims

Conditions
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Coagulation Defect, Snake Bites

Intervention / Treatment
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* Diagnostic Test: 20'Whole Blood ClottingTest (WBCT)
* Diagnostic Test: Modified Lee and White (MLW) Method Clotting Time


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All victims of snake bite presenting to the emergency department AND Consenting to be part of the study Exclusion Criteria: Those not providing a written informed consent OR Those on anticoagulants or antiplatelets OR With a known hematological disorder OR A known history of chronic liver disease OR Received antivenom or blood products following snakebite at another centre
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| snakebite victims<br>Victims of snakebite presenting to the Emergency Department of Jubilee Mission Medical College and Research Institute | Diagnostic Test: 20'Whole Blood ClottingTest (WBCT)<br>* 1ml of blood drawn from snake bite victims in clean glass test tubes of 1 cm diameter Kept undisturbed for a period of 20 minutes (measured by a stop watch). At the end of 20 minutes the tube is tilted to see if the blood has clotted or not. If a well formed clot is not formed, the test is recorded as 'abnormal'. If the clot seems well formed, it is further observed for a period of 30 minutes to look for dissolution of the formed clot and would be termed clot lysis. Clot lysis indicates an unstable clot.<br>* Other names: 20'WBCT;Diagnostic Test: Modified Lee and White (MLW) Method Clotting Time<br>* The blood collected in three additional test tubes would be utilised for MLW. The three test tubes would be kept on a rack at ambient temperature. The blood sample would be drawn in a 5cc syringe and 1 ml would be added in the three test tubes consecutively. The test tube would be left undisturbed for 5 minutes, after that the first tube would be tilted approximately to check for clot formation every 30 seconds while the other tubes are left undisturbed. After the blood in the first tube has clotted, the time would be noted and the second tube would be tilted every 30 seconds and examined. Following its clotting, the third tube would be examined. The time at which the third tube is recorded as the CT value. Once clotted, then the sample in the all three test tube would be assessed at 20 minute and 30 min to look for breakup or lysis of the clot.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensitivity and specificity of serial Modified Lee White Method(MLW) in comparison with twenty minute Whole Blood Clotting Test in detecting coagulopathy in snakebite victims. |  | 48 hours of snakebite | 
| Sensitivity and Specificity of admission Modified Lee White Method(MLW) and twenty minute Whole Blood Clotting Test in detecting coagulopathy in snakebite victims. | Comparing MLW and 20'WBCT to gold standard tests like Prothrombin Time (PT) and activated partial thromboplastin time (aPTT) | 48 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensitivity of admission 20'WBCT and MLW to diagnose Russells viper (Daboia ruselli) envenomation |  | 48hours | 
| Sensitivity of admission 20'WBCT and MLW to diagnose Hump-nosed pit viper (Hypnale hypnale) envenomation |  | 48hours | 
| Time to detection of hematotoxic envenomation in MLW and 20'WBCT |  | 48 hours | 
| Sensitivity and specificity of delayed reading of clotting time and clotting test at 30 minutes in detecting coagulopathy |  | 48 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Modified Lee and White Method, 20'WBCT, Whole Blood Clotting Test