Evaluation of the usefulness of the immunoradiometric method for post-mortem measurement of insulin concentration in the intraocular fluid: preliminary results

Introduction
In medicolegal practice, rare cases associated with suicidal, criminal or accidental overdose of insulin are both analytically and forensically challenging. The determination of insulin in post-mortem blood has limited diagnostic value, mainly on account of post-mortem chemical degradation processes (particularly hemolysis), and hence is not useful in medicolegal practice.

Aim of the study
The aims of the study were: 1) to assess the usefulness of the immunoradiometric method, used in clinical practice, for post-mortem measurement of insulin concentration in the intraocular fluid, 2) to preliminarily evaluate the usefulness of the obtained results for toxicological and medicolegal assessment, and 3) to verify on the basis of our own material the validity of the cited literature data on the effect of hemolysis on the result of insulin level determination in post-mortem blood.

Material and methods
The study material consisted of 93 samples of intraocular fluid collected during consecutive medicolegal autopsies performed in the Department of Forensic Medicine and Forensic Toxicology, Medical University of Silesia in Katowice. In addition, 10 samples of peripheral blood taken from living people (5 women and 5 men) for clinical and diagnostic purposes were analyzed. Insulin(e) IRMA KIT from IMMUNOTECH was used for the analyses.

Results
In 86 (92.5%) samples, the insulin concentration was below the analytical sensitivity of the method (less than 0.5 μIU/ml), while in 7 cases it was in the range of 1.42–24.42 μIU/ml.

Conclusions
Determination of the insulin level in the intraocular fluid by the immunoradiometric method provides an opportunity for objective verification of poisoning, however this claim requires further research.