General Rules or Specimen Collection

• Specimens should be obtained before antimicrobial agents have been administered.
• Use sterile technique in collecting the specimen.
• Be sure to cap specimens and ensure tube tops are firmly secured before submission.
• Provide an adequate amount of specimen. Call the laboratory with any questions about sample collection.
• If several cultures are requested, provide one sample for each culture.
• Specimens must be labeled with the name of the patient, the source of specimen, test being ordered and date of sample. If possible, the suspected disease should also be included.
• Transport tubes are provided by the laboratory at client's request. Be sure to keep culturettes and transport media on hand. Discard expired transport devices regularly.

Acid Fast Stain

Two unstained slides are required for acid fast testing. Label the slides with the patient name and source. Spread specimen evenly into thin film on center of the slide. Heat fix the slide.

Aerobic Culture and Culture & Sensitivity

Several specimen types are acceptable for aerobic culture. Specimens can be sent on Copan™ swabs (sterile swab with Amies transport gel). Biopsy specimens for culture should be sent in a sterile container with a small amount of sterile physiological saline. Specimens collected by syringe should be aseptically transferred to a sterile tube. Do not submit syringes. Specimens received in formalin or in EDTA are not acceptable for culture.

Swabs that contain mostly pus oten provide no-growth on cultures, due to the toxic efect of the white blood cells on bacteria. The most productive specimens are obtained by swabbing deep into an infected wound or obtaining fluids from an actively infected issue. Specimens should be refrigerated until pick up and transported with a cold pack.

Anaerobic Cultures

Anaerobic cultures should be submitted on a Copan® swab or Port-A-Cul Tube and processed within 48 hours of collection. These swabs are available from Antech at no charge. Culture containers that provide crush-ampules of liquid transport medium are not acceptable for anaerobic culture.

Proper collection of anaerobic samples is imperative for successful culture of anaerobic organisims. Several methods which avoid contamination by normal flora are: syringe aspiration of fistulous tracts or draining wounds, cystocentesis, thoracocentesis, use of guarded Teigland swabs, curettage or tissue biopsy. These are preferred methods of collection for anaerobic culture and should be performed when possible. After collection, keep specimen at room temperature as fastidious organisims may be lost otherwise. All anaerobic organisms are reported with drugs of choice.

Blood Culture

Specimens for blood culture require collection into specialized vacuum tubes containing growth medium. These blood culture bottles are available at no additional charge. Do not use tubes with citrate, EDTA, oxalate or heparin as an anticoagulant for blood. The specimen MUST be submitted in blood culture bottles. No other specimen type is acceptable.

Even though a small sample can provide some diagnostic information, a larger volume will more likely permit recovery of an infectious organism. The BEST specimen can be achieved by submitting an adequate amount of blood in paired bottles, drawn at multiple times, several hours apart.

Procedure

1. The venipuncture area should be shaved, gently cleaned with soap and water, and disinfected twice with an iodine preparation, beginning at the venipuncture site and working outward. Allow the site to dry.
2. Disinfect the rubber stopper of the blood culture tube with alcohol.
3. Split the specimen between two bottles. One will be vented for aerobic organisims and one will be incubated, closed, for anaerobic organisims. If only one bottle is submitted, it will be vented to isolate aerobes and facultative anaerobes.
4. 3 mls of blood is the optimal amount for each bottle but 2 mls are acceptable or culture. The vacuum in the tube is adjusted to draw 3 mls. DO NOT FORCE more blood into the tube, as excess blood volume can allow the white blood cells to overwhelm the nutrient broth and kill the organism.
5. Pairs of bottles can be collected 1–4 hours apart; to maximize the chance of recovering organism "showers" into the blood. A pair of bottles should be collected at each collection time, so that one bottle each can be incubated for aerobic and anaerobic growth.
6. Hold cultures at room temperature or at 37°C until they can be transported to the laboratory.

Campylobacter Culture

Stool samples for Campylobacter species should be submitted in a sterile container or Copan™ swab. Keep specimen at room temperature until pick up.

Cryptosporidium Stain

Two unstained slides are required for Cryptosporidium testing. Label both sides with the patient name and source. Spread specimen evenly into a thin film on the center of the slides.