Chulalongkorn Medical Journal


Background: Kratom (Mitragyna speciosa) is a plant commonly found in Southeast Asia. Kratom is one ofthe most abused substances as “a legal psychoactive drug or substance”. The main addictive substance ofkratom is mitragynine. In forensic toxicology, one of the common problems is that there is no insightful informationon mitragynine stability in human blood, so the study of the mitragynine stability would lead to the properstorage of the specimen containing mitragynine.Objective: To study mitragynine stability in human blood in common blood collection tubes.Methods: Mitragynine standard was spiked into the blood from the blood bank to get the sample concentrationof 500 ng/mL. The sample was divided into 3 groups of common blood collection tubes which were sodiumfluoride/potassium oxalate tube, Ethylenediaminetetraacetic acid tube and no anticoagulant tube. The concentrationsof mitragynine were then measured and recorded in the conditions after 1 day, 3 days, 5 days, 7 days, 14 days and30 days.Results: Comparing the mean concentration of mitragynine with the elapsed time in each tube, it was found thatthere was no statistical significance (P > 0.05) among the blood collection tubes. However, it was found thatthe mitragynine concentration in sodium fluoride/potassium oxalate tube was more stable than the others.The difference was statistical significance (P < 0.05) when the concentrations of mitragynine on day 1 and day14 were compared in sodium fluoride/potassium oxalate tube while the others revealed the decreasing mitragynineconcentration between day 1 and day 7.Conclusion: This study demonstrated the mitragynine stability in blood in the common blood collection tubesand revealed that the sodium fluoride/potassium oxalate tube was the appropriate collection tube. The limitationof the use of sodium fluoride/potassium oxalate tube to store blood sample for mitragynine determination wasabout 7 days.


Faculty of Medicine, Chulalongkorn University

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