Specimen Collection Guide
Testing accuracy is inherently dependent upon careful attention to the collection technique and specimen preparation.
- Please do not send any specimens in glass containers unless specified in the Online Testing Guide.
- Please do not leave needles on syringes, as this practice creates an unnecessary hazard to those transporting and receiving specimens and may invalidate results due to exposure to air.
- Specimens containing a preservative or anticoagulant should be mixed thoroughly.
- Avoid contamination with normal flora.
- If swabs are used, they must be placed in approved swab transport devices.
The proper selection of specimens is extremely important for the laboratory confirmation of anaerobic infection. Since anaerobes are the predominant flora of the mouth, intestinal tract, and vaginal tract, specimens incorrectly taken from these sites may produce results that may be misleading. Specimens should be collected in a closed system (syringe, transtracheal aspirates, needle punctures, etc.) from deep sites, bypassing normal flora. Do NOT send syringe; transfer aspirate to Port-A-Cul vial (BBL 21608), A.C.T. tube (Remel 12401/12402), or other anaerobic transport tubes.
Collect in anaerobic transport tube. Do not add any fluid. Replace stopper immediately.
Collect in sterile jar or petri dish. Larger tissue pieces do not require anaerobic transport tubes, since anaerobiasis is maintained inside the specimen for a reasonable length of time. DO NOT ADD FLUID (saline, formalin, or alcohol).
Collect in a syringe without air; use a small syringe for a small amount of fluid. Expel aspirate into Port-A-Cul vial or other anaerobic transport tube.
Return swab to the anaerobic transport tube which contains a reducing atmosphere and an indicator which is colorless in reducing conditions. Swabs are the least desirable specimens for anaerobic cultures. Avoid taking specimens with a swab if at all possible. Note: fungal and AFB cultures require additional samples in AEROBIC transport devices.
Avoid drawing blood from an indwelling catheter. If the specimen must be drawn through the catheter, indicate on the requisition. Not more than 3 specimens need be drawn in the initial 24-hour period.
Cannulas, IUD's, etc.
Submit in sterile containers. Note: Foley catheter tips are not useful for diagnosis of urinary tract infections.
Multiple Tests/Specimen Types
If two or more types of specimens (i.e., serum and plasma) are submitted on one patient, indicate the type of specimen and anticoagulant on each vial. Refer to the Online Testing Guide for specimen handling specifications.
Draw sufficient blood with the indicated anticoagulant to yield the required volume of plasma. Separate plasma as soon as possible, preferably by centrifugation. Transfer plasma to a plastic vial and indicate the anticoagulant used on the label. Avoid hemolysis, as some tests are invalidated by hemolysis.
Draw sufficient blood to yield the required volume of serum. Let specimens clot at room temperature unless otherwise specified, and separate serum within one hour, preferably by centrifugation. Transfer serum to a plastic vial unless otherwise specified. Avoid hemolysis, as some tests are invalidated by hemolysis.
First morning specimen is best. Reduce irrelevant flora by rinsing mouth and/or cleansing tracheostomy site. Instruct patient on the need for sputum rather than saliva. Collect specimen in a sterile container. A good specimen will show purulent material. If the specimen is watery and almost clear, it is probably saliva and is therefore inadequate for culturing.
Special specimen containers are available for all testing on stool specimens. To permit expansion, the container should not be more than half full.
Use only swabs approved for bacteriological examination and culturing. Q-tips and similar cotton tipped applicators may be bacteriostatic or bacteriocidal. Note: For Virology swab cultures see the Virology section.
May include throat, nasal, endocervical, urethral, rectal or vaginal sites. Firmly swab the area with a sterile, approved, cotton-tipped applicator. Return swab to plastic sleeve or insert swab deep into the transport medium and break the applicator just below the point where it was held.
Use the anticoagulant indicated. Indicate the anticoagulant used on the label. Do not allow to freeze.
Remove debris around the wound by gently wiping the area with cotton soaked in sterile saline or water (do not moisten the swab with fluid containing bacteriostatic substances or antibiotics). Obtain specimen from the most active site of the wound. Take care not to swab the normal skin area. Return swab to plastic sleeve or anaerobic transport device or insert swab deep into transport medium and break off applicator just below the point where it was held. On request form, clearly indicate site of wound.
It is of utmost importance to follow proper cleansing procedures for obtaining a clean catch or catheterized specimen. Submit in an approved transport device (BD urine transport which contains boric acid as a preservative) or refrigerate until transport. For Viral culture, clean catch urine without preservative is required. Morning voids have highest titers. See Microbiology Specimen Collection procedures [100k PDF*].
A timed urine specimen should be collected for most assays. Urine collection containers are available on request. Refer to the Online Testing Guide test menu for each assay to determine the appropriate type and amount of preservative. For timed collections, patients should be given two containers and instructed to avoid direct contact with collection bottles or bags containing preservatives, especially hydrochloric acid. Patients should receive explicit instructions for obtaining a complete timed urine sample.
Specimen containers should be labeled with the type of preservative added. See Appendix I: Urine Preservatives [32k pdf*], for appropriate urine preservatives.
Patient instructions for 24 hour urine collection:
- Avoid alcoholic beverages and vitamins for at least 24 hours BEFORE starting to collect urine and during the collection period. Do not discontinue medications unless instructed to do so by your physician, but inform the laboratory which medications you are taking.
- Start the timed collection period with the first morning void. DISCARD THIS VOIDING since the urine was formed prior to the collection period. Write the time on the container and requisition. COLLECT ALL SUBSEQUENT VOIDINGS UNTIL THE SAME TIME ON THE SECOND DAY, emptying the bladder and adding this last void to the collection container.
- All timed urine collection bottles should be REFRIGERATED during collection. Preservative may have been added to the container; this may be caustic. Please be careful not to spill any of the preservative. (If the patient has a catheter, the collection bag should be kept on ice between empties.)
- Inadequate preservative or loss of voided specimens are common errors encountered in the collection. As a guideline, START THE COLLECTION OVER if: a. any part of the specimen is lost. b. if diarrhea stool gets mixed with the urine.
- Measure and record the timed collection volume in the appropriate area on the test request form. Submit only the required aliquot of a well-mixed total collection. Refer to the Online Testing Guide test menu to determine the appropriate pH adjustment. Carefully following instructions for urine collections will avoid the necessity of recollecting specimens.
For random urines the patient should void into a clean container. The specimen should be labeled and refrigerated until pick-up. A clean-catch or midstream specimen is preferred. The patient should void a small amount of urine before collecting in a clean container.
The following is a list of tubes referred to in the Online Testing Guide test menu:
- ACD (Yellow-Top Tube)*:
This tube contains acid citrate dextrose (ACD), which is used for special tests using whole blood. Do not substitute the yellow top (SPS) tube. SPS additive interferes with several assays that use ACD blood.
- EDTA (Lavender-Top Tube)*:
This tube contains EDTA as an anticoagulant and is used for most hematological procedures. Do not allow to freeze.
- Lithium Heparin (Green-Top Tube)*:
This tube is used for the collection of heparinized plasma or whole blood for special tests.
- Potassium Oxalate/Sodium Fluoride (Grey-Top Tube)*:
This tube contains Potassium Oxalate as an anticoagulant and Sodium Fluoride as a preservative, used to preserve glucose in whole blood and for some special chemistry tests.
- PST (Lime Green Plasma Separator Tube)*:
This tube contains heparin and plasma gel separator and is used for many different tests. After drawing specimen, invert the tube to mix before centrifuging for 10 mins. If frozen plasma is required, pour off plasma into plastic vial and freeze. This is used for STAT orders.
- Serum (Red-Top Tube):
This tube contains no anticoagulant. The tube is used for the collection of serum for selected chemistry tests and special immunohematology tests. An SST tube should never be substituted as the gel barrier can interfere with analysis.
- Sodium Citrate (Light Blue-Top Tube)*:
This tube contains sodium citrate as an anticoagulant, used for collection of blood for coagulation studies. This tube needs to be completely filled, the ratio of blood to anticoagulant is critical for valid coagulation results. After the tube has been filled with blood, immediately invert the tube gently several times to prevent coagulation. Reference ranges for coagulation studies are based on tube containing 3.2% buffered sodium citrate.
- Sodium Heparin (Royal Blue-Top Tube)*:
This tube is for lithium ratios only.
- Special Tubes
Other tubes for collection of special tests are available upon request. Please contact Reference Laboratory Services Services before collection.
- SPS (Yellow Top Tube)*:
This tube is for blood cultures (routine and AFB) for Microbiology.
- SST Hemogard (5 mL) (Serum Separator Tube) - (Gold-Top Tube):
The new preferred SST tube is a plastic 5mL Gold Hemogard (BD#367989) and replaces the plastic 8.5 mL red/black marble top serum separator tube currently in use (BD# 367991). This tube is a serum separator tube with clot activator and barrier gel to separate serum from the clot below. This tube is used for common chemistry panels such as the Basic and Comprehensive Metabolic Panels, Lipid Panel, and Hepatic Function Panel and any individual tests contained in these panels. This tube should not be used for drug analysis since some drugs can bind to the gel and yield incorrect results.
*Note: After the tube has been filled with blood, immediately invert the tube gently several times to prevent coagulation.
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