Journal Published Online: 01 May 1998
Volume 43, Issue 3

Electrolyte Concentration Differences Between Left and Right Vitreous Humour Samples



Between-eye differences in electrolyte concentrations were studied in 200 medico-legal autopsies using an ion-specific electrode system. Taking the highest of the paired vitreous potassium concentrations, cases <15 mM/L were classified as biochemically nonputrefied (Cat.1, n = 124), cases 15 to 20 mM/L as early putrefaction (Cat.2, n = 51), and cases >20 mM/L as biochemically putrefied (Cat.3, n = 25). Mean paired vitreous sodium for all cases (n = 200) was 112 to 173 mM/L (mean 148, standard deviation (SD) = 8.9); between-eye differences were 0 to 8 mM/L (0% to 5.1% of mean), averaging 1.5 mM/L (1%) and with only one case (in Cat.3) outside instrument accuracy (±3 mM/L). Mean paired vitreous chloride for all cases was 73 to 124 mM/L (mean 109, SD = 7.8); between-eye differences were 0 to 9 mM/L (0% to 8.8% of mean), averaging 1.7 mM/L (1.5%) and with 5 of 200 cases outside instrument accuracy (±3 mM/L). Thus between-eye concentration differences of sodium and chloride are tolerable using this methodology. Previous reports of greater variability likely reflect errors introduced by sample manipulation prior to analysis. By contrast, between-eye differences in potassium in Cat.1 cases were 0 to 2.34 mM/L (0% to 21.8% of mean) averaging 0.37 mM/L (3.3%). Significant and erratic between-eye differences in potassium undermine the usefulness of vitreous potassium in estimation of time of death.

Author Information

Pounder, DJ
University of Dundee, Dundee, Scotland
Carson, DO
University of Dundee, Dundee, Scotland
Johnston, K
University of Dundee, Dundee, Scotland
Orihara, Y
University of Dundee, Dundee, Scotland
Pages: 4
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Stock #: JFS16187J
ISSN: 0022-1198
DOI: 10.1520/JFS16187J