Measurement of chemical analytes in vitreous humor: stability and precision studies.

The analytic accuracy and precision for measurement of chemical analytes in vitreous humor (VH) are critical if results are to be used in forensic pathology. The purpose of our study was to demonstrate the stability and the reproducibility of VH sodium, potassium, chloride, glucose, urea nitrogen, acetone, and beta-hydroxybutyrate in specimens obtained from both eyes in medical examiner cases. We also compared with calculated VH osmolalities. Small but significant increases were observed in VH electrolyte concentrations in specimens refrigerated 6-12 months: sodium pre 144 mmol/L, post 151 mmol/L; potassium pre 12.0 mmol/L, post 12.8 mmol/L; chloride pre 121 mmol/L, post 123 mmol/L. No differences were observed between eyes, and within-day precision for all electrolyte measurements were excellent, (<1%). Frozen specimens showed significantly higher measured (439 mOsmol/kg) as compared with calculated osmolality (305 mOsmol/kg), with 1% within-day precision and no significance between eye variation for glucose and urea nitrogen. In 20 of 24 medical cases selected for possible ketoacidosis, measurement of beta-hydroxybutyrate concentrations appears to be a promising diagnostic biomarker for confirming suspected ketosis in medical examiner cases by means of VH analysis.

Methadone-related deaths in Hennepin County, Minnesota: 1992-2002.

Methadone maintenance therapy (MMT) is the only currently established medical therapy for heroin addiction. However, MMT still remains controversial. In Hennepin County, Minnesota, methadone is one of the top ten drugs reported in medical examiner investigated deaths and one of the most commonly diverted pharmaceuticals. This report reviews the role of methadone in medical examiner deaths over a 10-year period, 1992-2002. We compare cause and manner of death (accidental, natural, suicide) and methadone blood concentrations for decedents who were members of MMT programs with illicit users and those prescribed methadone for chronic pain. Findings reveal that 65% of decedents with measurable blood methadone concentrations were not participating in MMT programs. A total of 96 cases were identified, with the majority white (90.5%) and male (76.8%). MMTP program members were the minority (34.7%) of the methadone positive deaths and 39% were illicit users. Fifteen percent were chronic pain patients with almost half of this group dying from overdose. Methadone concentrations of drug caused/related deaths (0.18-3.99 mg/L) overlapped with those of deaths not attributable to methadone (0.18-3.03 mg/L) with no definable lethal level. Interpretation of methadone blood concentrations must be done in the context of the clinical history for determining cause of death, and may be confounded by postmortem redistribution.