**6. Storage and transport**

*Oral and Maxillofacial Surgery*

the lymph node itself [5].

**5.1 Saliva**

sis of head and neck lesions.

*Saliva is useful for testing:*

b.For caries activity tests

**5.2 Collection of specimens**

collection.

for at least 1 day.

5.Collect saliva for 10 min [6].

a.As an index to metabolic processes

c.For detection of various metabolites in smokers

FNAC. FNAC of cervical lymph nodes is a well-accepted diagnostic test of choice in both adult and pediatric patients for reliably distinguishing between benign/ reactive and malignant processes and guiding patient management with simple observation or antimicrobial therapy for infections, chemotherapy and radiation therapy or the need for more sample tissue like core biopsies or excisional biopsy of

Thus FNAC is recommended as a safe, quick and inexpensive tool in the diagno-

Collection of human saliva offers a noninvasive method for monitoring the disposition of unbound (free) drugs and many endogenous biomarkers. Human genomic DNA extracted from buccal epithelial cells and white blood cells found in saliva can be used in various applications in diagnostics. The correlations between blood and saliva biomolecule/biomarker concentrations range from good to excellent. Methods of collecting saliva range from simply spitting into a collection cup or using absorbent pads or swabs or the trademarked collecting devices. Freeze-thaw techniques are often employed to help break up the mucin protein that is responsible for the sticky, foamy saliva. There are few inherent drawbacks for using saliva as an ideal biofluid. In some cases, the drug, metabolites or other compounds being assayed may bind to absorbent materials, thus reducing recovery or giving a misleading result [6].

Whole saliva is commonly collected by draining, spitting, suction, and swab or absorbent method. Common stimuli used are chewing on paraffin wax and chewing gum at a fixed rate. As described by Wong D, the proposal for standardized collection of whole and glandular saliva can be followed for saliva sample collection.

1.Collect saliva samples at the same time of the day between 9:00 and 11:00 a.m.

2.Patient should refrain from eating and drinking at least 90 min before advised

3.If present, drug usage should be stopped that might affect salivary secretion

4.Rinse mouth with preferably deionized water prior to the saliva collection.

Collection of saliva into ice-cooled vials is recommended to slow down the activity of hydrolytic enzymes present in saliva in air-cooled preset environment. Proprietary collection vials contain a cocktail of protease inhibitors and

**52**

After collection, salivary samples must be snapped frozen in liquid nitrogen. In the absence of liquid nitrogen, freezing in dry ice is a practical choice when samples are collected. For a prolonged storage, −80°C temperature is preferred over storage at−20°C. The salivary samples can be diluted with glycerol (1:1) before storage. For immunochemical analysis such as ELISA, the saliva can be stored frozen after dilution (e.g., 1:100) in the assay buffer, usually PBS—0.5% Tween-20. To maintain the integrity of the proteins, before testing, the deep-frozen samples must be thawed as quickly as possible. Analysis of pH (H+ and HCO4 <sup>−</sup>) and viscoelastic properties is best analyzed in fresh saliva samples. Storage of salivary DNA and RNA is similar to that of a salivary protein sample [6].
