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Bicarbonate/Total CO2, Urine

Urine Bicarbonate, Urine CO₂

Test Codes

Order as a Miscellaneous Send Out (LAB6433), ARUP: 20245.

Department

Send Outs

Specimen Collection Criteria

Collect: Random urine specimen in a screw-capped container (preferred) or other sterile collection cup. (Minimum: 0.3 mL)

• Minimize exposure of specimen to air.
• Critical frozen. Send specimen for processing immediately after collection.
• Separate specimens must be submitted when multiple tests are ordered.

Physician Office/Draw Specimen Preparation

Critical frozen. Immediately after collection, transfer urine to a plastic transport tube and freeze (-20°C/-4°F or below).

Preparation for Courier Transport

Transport: 4.0 mL urine in a plastic transport tube, frozen (-20°C/-4°F or below). (Minimum: 0.3 mL)

Rejection Criteria

• Specimens that are thawed and refrozen.
• Specimens not collected and processed as indicated.

In-Lab Processing

Critical frozen. Immediately after collection, transfer urine to a plastic transport tube and freeze (-20°C/-4°F or below).

Transport: 4.0 mL urine in a plastic transport tube, frozen (-20°C/-4°F or below). (Minimum: 0.3 mL)

Storage

Specimen Stability for Testing:

Room temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): 30 days (specimen cannot be thawed and refrozen)

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to ARUP Laboratories, Salt Lake City, UT.

Performed

Sunday – Saturday.
Results available in 2-4 days.

Reference Range

Normal ranges have not been established.

Test Methodology

Enzymatic.

Clinical Utility

Urinary bicarbonate may be useful in the investigation of renal tubular acidosis (RTA), however, Urine pH may give equally useful information. In a normal individual, urinary bicarbonate does not appear until the serum level reaches 24-26 mmol/L. The appearance of bicarbonate at a low serum bicarbonate suggests type 2 RTA. It can be assumed that bicarbonate is being excreted if the urine pH > 6.1.

CPT Codes

82374

Contacts

Last Updated

4/8/2024