The healthcare provider is responsible for collecting specimens for diagnostic examinations. Because procedures vary, check institutional protocols for specimen retrieval, transport, and preservation, and reporting of test results.

Specimens for bacterial culture should be representative of the disease process. Also, sufficient material must be collected to ensure an accurate examination. As an example, serous drainage from a diabetic foot ulcer with possible osteomyelitis may yield inaccurate results. In this case, a bone biopsy or purulent drainage of infected tissue would be a better specimen. Likewise, if there is a lesion of the skin and subcutaneous tissue, material from the margin of the lesion rather than the central part of the lesion would be more desirable. If a purulent sputum sample cannot be obtained to aid in the diagnosis of pneumonia, blood cultures, pleural fluid examination, and bronchoalveolar lavage (BAL) specimens are also acceptable.

It is imperative that material be collected where the suspected organism is most likely to be found, with as little contamination from normal flora as possible. For this reason, certain precautions must be followed routinely:

1. Observe standard precautions.

2. Clean the skin starting centrally and going out in larger circles. Repeat several times, using a clean swab or wipe each time. If 70% alcohol is used, it should be applied for 2 minutes. Tincture of iodine requires only 1 minute of cleansing.

3. Bypass areas of normal flora; culture only for a specific pathogen.

4. Collect fluids, tissues, skin scrapings, and urine in sterile containers with tight-fitting lids. Polyester-tipped swabs in a collection system containing an ampule of Stuart transport medium ensure adequacy of the specimen for 72 hours at room temperature.

5. Label specimen with the patient’s name, date, and test(s) ordered and place the specimen in a biohazard bag.