The usefulness of culture result information is directly proportional to the quality of the specimen provided to the laboratory.

General Guidelines

  • Collect specimen before antibiotic therapy. If this is not possible, specify antibiotic on requisition.
  • Notation of diagnosis, foreign travel, animal contact, immunosuppressive disease, or suspected organism is helpful.
  • First morning specimens are usually preferred, especially if urine or sputum specimens for TB.
  • Specimens collected on swabs are not acceptable for AFB or fungal cultures. The optimal specimen for anaerobic or aerobic culture is an aspirate or tissue. View guidelines for choosing the correct swab or container for the test.
  • Avoid contamination of the sample with normal flora by decontaminating surface area prior to collecting the specimen. Contamination can usually be evaluated by the number of epithelial cells seen on gram stain examination. It is preferable to obtain specimens bypassing normal flora whenever possible. For urines, single catheterized specimens are cleaner than midstream clean catch specimens. Deep wounds collected by aspiration are preferable to superficial swab collection. For sputum specimens, having the patient rinse their mouth before expectorating may reduce oral-pharyngeal contamination.
  • Do not allow swabs to dry out. Follow instructions for proper use of specimen collection devices provided with each unit. Use no fixatives or bacteriostatic agents for cultures. View guidelines for choosing the correct swab or container for the test.
  • Collection kits are available from the laboratory for ova and parasite exams. If not placed in preservatives, specimens must be received in the laboratory within one hour of collection.
  • For hospital patients and on-site clinics, deliver to laboratory within 2 hours, sooner if possible. Deliver immediately if results are needed STAT. Urine can be refrigerated if delivery is delayed. Rapid delivery is especially important for CSF specimens, stools for O & P examination, Neisseria cultures, and anaerobic specimens.
  • For off-site clinics or doctors’ practices, various transport systems are available. Please contact the laboratory for provision of required transport tubes or, if necessary, STAT pickup. Note: Due to the instability of Neisseria gonorrheae, specimens for GC culture from off-site clinics should be collected in transport media.
  • Call the laboratory before collection of specimens for malaria so processing can begin immediately upon receipt.
  • Anaerobic transport media is available from General Stores. Anaerobic transport media is usually not necessary if the specimen is delivered to the laboratory immediately.
  • Whenever submitting body fluid for culture, send the fluid in a sterile container specifically for microbiology. Do not inoculate blood culture media except for peritoneal fluid and also send uninoculated fluid in a sterile container.
  • Positive culture plates are held for seven days in the event that non-routine antimicrobial susceptibility testing is requested.
  • Late add requests for urine cultures cannot be honored if the specimen has been in the laboratory more than twelve hours.

Procedures for Obtaining Blood Cultures

See University of Colorado Hospital Blood Culture Procedure and Blood Culture Job Aid.

Rapid Strep Throat Swab Collection

Rapid Strep Sample Requirements.

Stat Gram Stain

STAT Gram stains on cerebrospinal and other body fluids are available 24 hours per day. All critical positive Gram stains (blood cultures, body fluids, cerebrospinal fluid, etc.) are called to the physician. Refer to Critical Lab Values.

Note: Culture requests may generate additional standard microbiologic procedures as required for identification of potential pathogens.