Recovery of protein from tear fluid stored in cellulose sponges

Human tear fluid collected in glass capillaries was absorbed in cellulose sponges. After various time intervals the recovery was measured for total protein, amylase (AMY), lysozyme (LZM), immunoglobulin A (IgA) and lactoferrin (LF). After one day storage at 4 degrees C of moistened sponges of at least 92% recovery was observed. Storage for longer periods at 4 degrees C up to seven days showed a decreasing recovery for total protein, AMY and IgA. Tear collection with sponges and storage of wet sponges for maximally one day at 4 degrees C followed by centrifugation or storage of the fluid at -20 degrees C are reliable ways of sample treatment.