NEW METHOD TO ASSESS DILUTION OF SECRETIONS FOR IMMUNOLOGICAL AND MICROBIOLOGICAL ASSAYS

Accurate quantitation of pathogens and antibody concentrations in secr etions has been difficult because of unpredictable dilution of secreti on with the diluent at the time of sample collection. We added an iner t substance, lithium chloride (LiCl), to the sample diluent and measur ed its concentration with an atomic absorption spectrometer before and after the specimen was added. LiCl, at a concentration of 2 mmol of L i per liter, has no negative effect on the survival of common respirat ory pathogens or on the results of immunoassays. The method is applica ble to any sample collecting in which dilution of the specimen is nece ssary.