The proper collection of a specimen for culture is the most important step in the recovery of pathogenic organisms responsible for infectious disease. A poorly collected specimen may lead to failure in isolating the causative organism(s) and/or result in the recovery of contaminating organisms.
Basic Concepts for Specimen Collection
- Collect the specimen from the actual site of infection, avoiding contamination from adjacent tissues or secretions.
- Collect the specimen at optimal times (for example, early morning sputum for AFB culture).
- Collect a sufficient quantity of material. Use appropriate collection devices: sterile, leak-proof specimen containers. Use appropriate transport media (anaerobe transport vials, Culturette for bacterial culture, Cary-Blair for stool culture, M4RT for viral and Chlamydia cultures, and urine boric acid transport. Check expiration date before inoculating collection device.
- Whenever possible, collect specimens prior to administration of antimicrobial agents.
- Properly label the specimen and complete the test request form. The specific source of specimen is required. Example: wound, left leg.
- Minimize transport time. Maintain an appropriate environment between collection of specimens and delivery to the laboratory.
- If appropriate, decontaminate the skin surface. Use 70-95% alcohol (ALC) and 2% chlorhexidine or 1-2% tincture of iodine (TIO) to prepare the site. Allow a contact time of two minutes to maximize the antiseptic effect.
- For the orders with more than one test, ensure that the proper transport is utilized. (For example, anaerobic culture requests need to be submitted in anaerobic transport media; bacteriology requests should not be in viral media; AFB requests should not be in anaerobic transport media.
Other Useful Links for Nurses: