Comprehensive evaluation of pericardial biochemical markers in death investigation.

Pericardial fluid (PCF) is a well-preserved cadaveric material in cases without structural damage. The present study investigated fundamental serum components of PCF, including total proteins (TP), albumin (Alb), urea nitrogen (UN), creatinine (Cr), uric acid (UA), glucose (Glu), sodium (Na), potassium (K), chloride (Cl), calcium (Ca) and magnesium (Mg) in PCF with regard to the postmortem and survival periods, and cause of death in serial medicolegal autopsy cases (n=288) with intact pericardial and cardiac structures within 48h postmortem. The amount of PCF (mostly 5-25ml) showed no survival or postmortem time dependence, or difference among the causes of death. For all cases, there were moderate postmortem decreases of Na and Cl, and increases of K and Mg, which were insufficient for application to estimate the time since death; however, characteristic findings with regard to the cause of death were detected in cases of hours-long survival, especially in 'functional causes of death': higher Alb, UN, Cr, UA, K and Mg, and lower Na, Cl and Ca in intoxication; lower TP, Alb, Cr, K and Mg, and higher Na and Cl in hypothermia (cold exposure); higher Alb, UN, Cr, UA and Mg, and lower Glu and Ca in hyperthermia (heatstroke). These observations suggest the usefulness of pericardial biomarkers for investigating the cause and process of death to reinforce pathological and toxicological findings.