THE RELIABILITY OF SALIVA AS A SAMPLE FOR THE DETECTION OF HEPATITIS-A IMMUNOGLOBULINS UNDER VARIOUS SAMPLING CONDITIONS

Background: Saliva is increasingly being investigated as an alternativ e to serum for diagnostic and epidemiological testing even though anti body levels are substantially lower in buccal cavity fluids. However, there has been little study on whether buccal cavity activity and/or t he timing of saliva sampling affects the diagnostic outcome, particula rly in seropositive subjects. The absence of influence by these factor s may be critical to the use of saliva for pre-vaccination screening f or example. Objectives: The effects of eating, brushing of teeth and c ircadian rhythm on the measureable salivary immune status of 42 health y individuals known to be serum and saliva anti-HAV positive were exam ined. Study design: A total of 141 saliva samples obtained from the 42 healthy subjects, before and after meals, before and after brushing o f teeth and at various timepoints throughout the day, were assayed for total anti-HAV using an in-house saliva based enzyme-immunoassay, pre viously shown to have a 100% correlation in terms of sensitivity and s pecificity with a serum based assay. Results: The results indicated th at total anti HAV titres varied according to the time of day and that eating had no significant effect on the total anti-HAV titre, but brus hing of teeth did. Titres never varied to the extent that a result was falsely negative at any timepoint. Conclusion: These results confirm the usefulness of saliva as a diagnostic sample for the detection of h epatitis A antibody, regardless of sampling times, eating or tooth-bru shing. (C) 1997 Elsevier Science B.V.