Urine and Stool Specimen

24-hour urine collection

The preferred time for a 24-hour urine collection is 6 a.m. to 6 a.m. the following morning. However, any 24-hour period is acceptable as long as the opening and closing times are indicated on the specimen container. Only one first morning void must be included.

24-hour urine specimens must be collected in a plastic, brown, graduated urine container. These containers can be obtained from the inpatient/outpatient unit or an outpatient pharmacy. It is preferable that the collection be refrigerated and delivered promptly. The start date and time, and end date and time must be indicated.

The container must be labeled with the patient’s name and unique identification, such as the medical record number or date of birth.

Note: While timed urine collections encompassing a 24-hour period are preferable, collections of shorter duration may be accepted in certain cases (e.g., pediatric patients).

Patient instructions

  1. Void and discard urine for the starting time.
  2. Begin saving all urine in a container from this time on for 24 hours.
  3. Refrigerate the container during collection.
  4. Void at the end of the 24-hour period and add it to the container.
  5. Report any loss of urine. Urine must not be removed for other purposes, such as other testing or research testing. The Laboratory Service Center must receive the entire 24-hour sample.

Collection with acid preservative

For specimens with acid preservatives, 25 milliliters of 50 percent acetic acid must be added at the start of collection. The acid preservative bottle can be obtained from an outpatient pharmacy.

The following are examples of tests that require an acid preservative:

  • 5HIAA
  • Catecholamines
  • DALA/ALA
  • HVA
  • Metanephrines
  • VMA

Collection without acid preservative

For specimens without acid preservatives, 24-hour urine is collected in a brown bottle with no preservative. These containers can be obtained from the clinic or an outpatient pharmacy.

The following are examples of tests that can be performed on a 24-hour collection with no preservative:

  • Citrate
  • Copper
  • Heavy metal screen
  • Mercury
  • Oxalate
  • Porphobilinogen qualitative/quantitative (protect from light, use brown bottle or wrap in foil)
  • Porphyrin screen/fractionation (protect from light, use brown bottle or wrap in foil)

Random urine collection

A random, clean-catch urine specimen should be collected in a blue-capped, BD Vacutainer urine collection cup. The container must be labeled with the patient’s name and unique identification, such as the medical record number. The instructions for clean-catch, midstream urine collection are given to the patient.

Procedure

After collection, the sealed blue-capped container is returned to the healthcare worker. Urine will be transferred to both a gray top and yellow top tube. If there are orders for a urine culture, the healthcare worker will:

  • Transfer the specimen from the urine cup into a gray-top tube containing boric acid by removing the seal from the blue cap and inserting the gray-top tube through the blue cap and onto the needle.
  • Once the fill-line has been reached, the tube is removed and mixed immediately by gently inverting it 8 to 10 times (holding the tube upright, gently invert it 180 degrees and back to complete one inversion).

If there are orders for urinalysis, the healthcare worker will transfer the specimen from the urine cup into a yellow-top tube, which is then inserted onto the needle.

If there are orders for additional urine tests, the blue cap is carefully removed from the cup and the urine is poured into a wide-mouth, tightly-sealable, screw-cap container.

All specimen tubes and containers must be labeled with the patient’s name and unique identification, such as the medical history number. The healthcare worker must not send the blue-capped urine container through the pneumatic tube system or via courier.


Timed stool collection

Timed fecal specimens must be collected in Mayo stool containers (these are available from the Laboratory Service Center 773.702.1316). Containers must be obtained before collection is started. The start date and time, and the end date and time must be indicated on a timed collection. The container must be labeled with the patient’s name and unique identification, such as the medical record number.

The following is an example of a test requiring a timed collection:

  • Quantitative fecal fat

Random stool collection

Random fecal specimens must be collected in Mayo stool containers (these are available in the Laboratory Service Center 773.702.1316). Containers must be obtained before collection is started. The container must be labeled with the patient’s name and unique identification, such as the medical record number.

The following are examples of tests that can be performed on random collections:

  • Alpha 1 anti-trypsin
  • Qualitative fecal fat