Measuring salivary cortisol in studies of child development: watch out--what goes in may not come out of saliva collection devices

Technical advances that enable the noninvasive measurement of biomarkers in saliva have spawned a generation of investigations that integrate biological variables into behavioral and developmental research. This study examines whether the collection of saliva, using common absorbent devices compromises the measurement of cortisol when saliva specimens have low sample volume. Within subjects (n = 20), saliva samples were prepared to experimentally represent a gradient of lower to higher sample volumes. One aliquot was immediately frozen (no treatment control) and the remaining aliquots were absorbed ("collected") using one of three collection techniques employed in studies of child development (e.g., braided cotton dental rope, Salivette cotton pledget, or hydrocellulose microsponge). The sample volume recovered from each device relative to the initial volume available to be absorbed, and cortisol level recovered from each device relative to the untreated-control condition were measured. Results reveal that for certain collection devices (1) the percent volume recovered is related to the initial volume available to be absorbed, (2) a substantial percentage of cortisol in saliva specimens can remain in absorbent material, and (3) the percent of cortisol recovered can be associated with the initial sample volume available to be absorbed. When research participants, such as young children, produce low volume saliva specimens, some absorbent devices may have the potential to introduce error variance in the measurement of salivary cortisol.     

Anti-HIV antibody in saliva: an assessment of the role of the components of saliva, testing methodologies and collection systems

The various components of saliva, namely mixed saliva, parotid saliva, submandibular saliva, crevicular fluid and minor (labial) gland secretions, were collected from 63 known HIV antibody seropositive patients. A commercial test system. Wellcozyme HIV 1+2, and an antibody capture ELISA (GACELISA). were compared for sensitivity against all components. Sensitivity of the GACELISA system was 100%. in 123 mixed saliva, 121 parotid saliva and 127 labial fluid samples, and 98% in 99 submandibular samples and 127 crevicular fluid samples. Respective figures for Wellcozyme 1+2 were 92%, 55% 73%, 66% and 63%. Mixed saliva was most easily, conveniently and effectively collected using a plain Salivette. In 241 Salivette samples examined from the 63 patients. GACELISA proved 100% sensitive, and Wellcozyme 95% sensitive. Another form of Salivette impregnated with citric acid was unsuitable for GACELISA and gave a false negative value of 45%. In 197 samples from the gingival margin taken by a dry swab. GACELISA showed a sensitivity of 98% and Wellcozyme 81%. The most sensitive method for demonstrating anti-HIV antibody in saliva is to collect mixed saliva with the plain Salivette system and assay anti-HIV antibody levels by GACELISA.     

Newer saliva collection methods and saliva composition: a study of two Salivette® kits

Saliva is frequently used as a diagnostic fluid and several collection devices have been developed.
OBJECTIVE: The aim of the present study was to investigate the validity and reliability of two types of Salivette^® collection kits (non-covered cotton roll and polypropylene covered polyether roll) relative to conventional collection of saliva using paraffin wax chewing stimulation.
MATERIALS AND METHODS: Whole saliva samples were collected from 16 healthy volunteers. Following a cross-over design saliva was collected in a standardized way. The flow rate was determined and saliva samples were analyzed for pH, buffer capacity, electrolytes and protein/glycoprotein content.
RESULTS: We find that Salivette® methods do not allow evaluation of flow rate. pH was unaffected but buffer capacity was lower in Salivette® collected than in paraffin wax-stimulated saliva. The non-covered cotton rolls reduced the content of Na⁺ K⁺ CI^- as well as glycoprotein markers (hexosamines, fucose, sialic acid), lysozyme, lactoferrin, salivary- and myeloperoxidase but increased the concentrations of Ca²⁺ PO^3–₄ and SCN-. Polypropylene covered polyether rolls affected saliva composition less than the non-covered cotton rolls. Thus, SCN- and slgA concentrations were higher and lysozyme activity lower in the former (covered roll) saliva than in paraffin wax saliva. The reliability of the Salivette® kits was good.
CONCLUSION: We conclude that the Salivette® method generates data significantly different from conventional paraffin wax-stimulated saliva such as buffer capacity and several electrolytes and organic components. Care should be taken in interpreting the results when such methods are employed.