Uptake and loss of tears from filter paper discs employed in lysozyme tests.

Aspects of the use of filter paper discs in collecting tear samples for lysozyme tests were studied by serial weighings of bijoux bottles and tear-moistened discs. Blotted discs carried from 1.9 to 3.6 mg tears, but for practical purposes no deposit was left in the bottle. Unblotted discs carried a greater quantity of tear fluid, but the majority deposited a proportion of this in the bottle, and a correcting factor is therefore proposed for the lysozyme assay technique of Mackie and Seal. Substantial vaporisation of tears occurred within the bottles.