The effects of storage time and temperature on recovery of salivary secretory immunoglobulin A.
OBJECTIVE
This study aimed to determine the optimal storage temperature to minimise degradation of salivary s-IgA for field-based surveillance applications in resource-limited settings.


METHODS
Saliva samples from 40 Zambian adults were stored at +25°C, +4°C, -20°C, and -80°C and each tested by ELISA for salivary s-IgA concentration at 0, 1, 2, 7, and 15 days. Differences were determined among concentrations over time and temperature compared with baseline values. Kruskal-Wallis tests were applied to analyse variance. Single and multivariate regression analyses estimated the influence of storage time and temperature on recoverable s-IgA.


RESULTS
Results revealed a statistically significant decrease in salivary s-IgA concentration as storage time increased and as temperature decreased. Degradation during storage time was most pronounced at lower temperatures.


CONCLUSIONS
s-IgA is stable at ambient temperatures in Zambia for at least 15 days, suggesting no need for cold chain handling before analysis in field-based surveillance applications.
Department of Disease Control, London School of Hygiene and Tropical Medicine, Faculty of Infectious and Tropical Diseases, London WC1E 7HT, United Kingdom.
Elise
E
Presser
Michelo
M
Simuyandi
Joe
J
Brown
D000328:Adult; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012463:Saliva / Q000737:chemistry*; D013048:Specimen Handling / Q000379:methods*; D013696:Temperature; D013997:Time Factors; D055815:Young Adult; D015024:Zambia
D007071:Immunoglobulin A, Secretory