The subjects underwent pre-test counselling by professional
counsellers in the local language. Informed written consent was
obtained subsequently. According to the manufacturer’s instructions,
patients were advised to rinse their mouth thoroughly prior
to testing. Dehydrated patients were requested to drink plenty of
water to keep their mouth hydrated prior to testing. After this,
the patients were asked to tilt their head forward to prevent
swallowing of saliva. Light external massage of the cheeks and
gums for 15–30 s was carried out by the patients themselves, thus
increasing the quantity of gingival crevicular fluid (GCF) with a
consequent increase in IgG [15]. Subsequently they were asked to
spit, taking care not to expectorate, into the cup provided, till it
was at least half full. Sialogogues such as Vit. C were not used as
they interfere with the buffer solution of the kit (Manufacturer’s
communication). Room temperature was approximately 26 8C with
humidity approximately 30% at Panchgani and 50% at Mumbai