The correlation of methamphetamine concentrations in hair root, blood and urine in postmortem cases

Abstract

Methamphetamine (MA) is classified as the Schedule I Narcotic drugs according to Thai Narcotic Act B.E. 2522. Its widespread and addictive uses are currently a national threatening issue in many countries. Determination of MA in biological samples (mostly urine and blood) is used to assess illicit MA uses in forensic as well as in clinical purposes. In some circumstance, both samples are not available or contaminated; hair root is purposed as an alternative sample representing the recent MA uses before death. This study aimed to assess the correlation of MA concentrations in hair root and blood/urine samples in postmortem cases. Hair root, blood and urine samples were collected from 30 Thai deceased whose urine samples were MA positive in the screening test with MA strips test. After the washing process, hair root of 1 mg was detected by Gas chromatography/mass spectrometry triple quadrupole (GC/MS/MS). Blood and urine samples were extracted by liquid/liquid extraction and detected by GC/MS/MS. The results showed that MA concentrations in hair root vs blood, hair root vs urine, and urine vs blood were linearly correlated with the correlation coefficient (r) of 0.904 (p<0.001), 0.572 (p=0.001), and 0.690 (p<0.001), respectively. The corresponding linear regression equations were y = 1.997x - 162.620, y = 77.618x - 683.460, and y = 0.011x + 130.210, respectively. Verification of the regression equations was performed using MA concentrations in hair root of an additional 20 decease to calculate MA concentrations in blood and urine. It was shown that calculated and measured concentrations in both samples were not statistically different. Results from this study suggested hair root as an alternative specimen in case that blood or urine are not available.