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Beaumont Laboratory

Sodium and Potassium, Urine

Urine Sodium and Potassium, Urine Sodium/K, Urine Na/K, Antrim #17125, EPIC: LAB5454, SOFT: NAKU

Instructions

Note: 24 hour and random urine specimens MUST be collected separately. See below for collection criteria.

Specimen Collection Criteria

Collect: 24 hour urine or timed urine specimen with a 24 hour urine container with no preservatives.
Also acceptable: Random urine specimen in a screw-capped container (preferred) or another sterile collection cup. Preservatives are not acceptable for random urine specimens. (Minimum: 20 mL)

  • Refer to the table of Urine Preservative Options when multiple tests are requested.
  • Keep 24 hour urine specimen iced or refrigerated during collection.
  • Include start and end dates and times for the collection period on the specimen container.
Urine Preservative Options
No Preservative
6N Hydrochloric Acid
Boric Acid (10g)
Sodium Carbonate
50% Acetic Acid
Preferred
Acceptable
Acceptable
Unacceptable
Unacceptable

Physician Office/Drawsite Specimen Preparation

Maintain specimens refrigerated (2-8°C or 36-46°F) prior to transport.

Preparation for Courier Transport

Transport: Entire 24 hour urine collection, or random urine, refrigerated (2-8°C or 36-46°F).

Rejection Criteria

  • Specimens not collected and processed as indicated. 

Storage

Specimen Stability for Testing:

Room temperature (20-26°C or 68-78.8°F): 4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): For longer storage.

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days (Royal Oak and Troy store an aliquot for 30 days.)

Laboratory

Farmington Hills Chemistry Laboratory.
Grosse Pointe Chemistry Laboratory.
Royal Oak Automated Chemistry Laboratory.
Troy Chemistry Laboratory.

Performed

Sunday - Saturday.
Results available within 24 hours.

Reference Range

Sodium: 40 - 220 mmol/24 hours.
Potassium: 25 - 100 mmol/24 hours.
Normal ranges for random urines or for collections other than 24 hours have not been established.

Test Methodology

Potentiometry.

Interpretation

  • Urinary sodium levels less than 10 mmol/L are associated with extra-renal sodium loss (GI or sweat), pre-renal azotemia, severe volume depletion, and edematous states. Levels greater than 10 mmol/L are seen in acute tubular necrosis, SIADH, Addison's disease, and renal salt wasting.
  • Urine potassium levels less than 20 mmol/L are associated with non-renal conditions, while levels greater than 20 mmol/L are usually due to renal causes. Potassium loss is likely to occur in primary aldosteronism.

Clinical Utility

  • Urinary sodium measurements aid in the evaluation of patients with acute oliguria (low urine output), hyponatremia, and volume depletion.
  • Urinary potassium measurements are used to monitor electrolyte balance in the diagnosis and treatment of disease conditions characterized by low or high blood potassium levels.

CPT Code

84133, 84300.

Test Codes

Antrim #17125, EPIC: LAB5454, SOFT: NAKU

Last Updated

12/06/2017

Microtainer® and Vacutainer® are registered trademarks of Becton, Dickinson and Company.
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This directory currently reflects information only for specimens collected and/or processed at the Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.