Enzyme-linked immunoabsorbent assay for plasma thyroglobulin following compression of the neck.

A highly sensitive enzyme-linked immunosorbent assay (ELISA) for determination of plasma thyroglobulin (Tg) which we devised was applied to the postmortem diagnosis of external compression of the neck. The coefficients of variation within and between assays were 2.4-6.6% and 6.8-12.0%, respectively. A significant correlation was observed between Tg levels measured by our ELISA and those measured by radioimmunoassay (r = 0.996, P less than 0.001). Plasma Tg levels in all 36 cadavers without external compression of the neck or neck injuries were lower than 200 ng/ml (73.6 +/- 51.9 ng/ml, M +/- S.D.) although these levels were a little higher than those in living bodies (16.7 +/- 11.8 ng/ml). On the other hand, plasma Tg levels in most of 42 victims of asphyxia due to external compression of the neck were higher than 200 ng/ml (2190 +/- 4300 ng/ml), and the highest one was 24,600 ng/ml. Plasma levels of the other thyroid hormones and thyroid-stimulating hormone were determined in some cases, and the cervical conditions in certain cases of strangulation were analyzed. Present results suggest that Tg was released by mechanical force on the thyroid gland added at the agonal stage. The determination of plasma Tg level in a cadaver using our ELISA would seem to be useful for the postmortem diagnosis of the presence of external compression of the neck. Although thyroid diseases causing elevated Tg levels are rare in forensic cases, they should be excluded by routine histology of the thyroid at autopsy, so that the finding of a high Tg level would thus carry more weight when given in evidence.