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Sodium and Potassium, Whole Blood

Test Codes

EPIC: LAB5365, NAKW

Department

Chemistry

Instructions

Sodium and Potassium, Whole Blood should ONLY be collected at the Dearborn, Grosse Pointe, Royal Oak, Taylor, Trenton, Troy, or Wayne Hospital Campuses. Specimens should not be collected at any other Beaumont Laboratory drawsite, nursing home, or Outreach office. 

Specimen Collection Criteria

Collect: One Dark Green-top Lithium Heparin tube. (Minimum Whole Blood: 1.0 mL) or one blood gas syringe (see Blood Gas Procedure below).

Venous or arterial blood is required for adults. If heel-stick is necessary in neonates or fingerstick in pediatrics, minimize exposure of the sample to air during collection.

See Minimum Pediatric Specimen Requirements.

NOTE:  Blood Gas Syringe specimens should ONLY be collected at the Dearborn, Farmington Hills, Grosse Pointe, Royal Oak, Taylor, Trenton, Troy, or Wayne Hospital Campuses. Specimens should NOT be collected at any other Beaumont Laboratory drawsite, Nursing home, or Outreach office.

Collection Procedure for Blood Gas Syringes ONLY:

• A 1 mL or 3 mL plastic syringe containing dry heparin is usually used to collect the specimen.

• At least 1-2 mL (0.3 mL for pediatric patients) of blood is needed to ensure proper assay.

• Arterial specimens are collected by a physician, nurse, or respiratory therapist.

• For specimens collected by syringe, any air bubbles present in the syringe must be immediately expelled, the needle removed, and the syringe tightly capped.  The syringe is rolled between the palms of the hands to ensure mixing.

NOTE:  The Radiometer safePico Self-fill™ syringe has a metal ball to ensure homogeneous mixing when the syringe is rolled between the palms of the hands.

• Characterization of oxygen enrichment, at the time of arterial puncture, is required. This may be expressed as FiO2 fractional inspired oxygen concentration provided (e.g., 0.50), FiO2% (e.g., 50%), room air, or nasal cannula flow rate in liters per minute. The FiO2 must be noted on the requisition or entered as part of the electronic order for any arterial blood gas specimens. FiO2 is not required for venous blood gas orders.

• The specimen must be properly labeled.

• Place on wet ice for transport. Ice and Specimen must be kept separated. 

  Suggested:  Place specimen in front pocket of the biohazard bag.  Place ice in zip lock section of biohazard bag.

• The specimen must be transported immediately to the STAT Laboratory (Royal Oak) or to the Chemistry Laboratories.

Physician Office/Draw Specimen Preparation

For Lithium Heparin tubes (Dark Green) ONLY:

DO NOT remove Vacutainer^® stopper. Arrange for transportation to the Laboratory immediately.  Maintain whole blood specimen at room temperature prior to transport. (Minimum 0.5 mL)

Preparation for Courier Transport

Transport:  Whole blood specimen, room temperature. (Minimum 0.5 mL)

Rejection Criteria

• Specimen in which significant delays occur before arrival in the Laboratory (greater than 2 hours).
• Clotted specimens.
• Specimens not collected and processed as indicated.

Inpatient Specimen Preparation

• Transport the Lithium Heparin specimen STAT to the STAT Laboratory (Royal Oak) or Chemistry Laboratories.
• If a blood gas syringe specimen was collected, transport STAT, on wet ice, to the STAT Laboratory (Royal Oak) or the Chemistry Laboratories.

In-Lab Processing

Immediately analyze the whole blood, heparinized specimen upon receipt in the Laboratory.

Storage

Specimen Stability for Testing:

Dark Green Lithium Heparin Tubes:

Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 1 hour
Frozen (-20°C/-4°F or below): Unacceptable

Blood Gas Syringes:

Room Temperature (20-26°C or 68-78.8°F):  Unacceptable
Refrigerated (2-8°C or 36-46°F): 1 hour
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Dark Green Lithium Heparin Tubes:  Refrigerated (2-8°C or 36-46°F): 7 days
Blood Gas Syringes:  Specimens are disposed within 8 hours of testing.

Laboratory

Dearborn Chemistry Laboratory
Grosse Pointe Chemistry Laboratory
Royal Oak STAT Laboratory
Taylor Chemistry Laboratory
Trenton Chemistry Laboratory
Troy Chemistry Laboratory
Wayne Chemistry Laboratory 

Performed

Sunday – Saturday, 24 hours a day.
Results available within 30 minutes of receipt in the Laboratory.

Reference Range

Sodium
Adult range: 135-145 mmol/L.

Age related reference range:

Age	Range (mmol/L)
0 - 1 day	126-166
2 - 29 days	134-144
30 days - 1 year	139-146
Greater than 1 year - 12 years	138-145
13 years - adult	135-145

Potassium
Adult range: 3.5-5.2 mmol/L.

Age related reference range:

Age	Range (mmol/L)
0 - 1 day	5.0-7.5
2 days - 3 months	4.0-6.2
4 months - adult	3.5-5.2

Test Methodology

Potentiometric.

Interpretation

See Sodium and Potassium assays.

Clinical Utility

This assay is appropriate when rapid turnaround time is important for patient management.

CPT Codes

84132, 84295.
LOINC:  Potassium 2823-3, Potassium Whole Blood 6298-4

Contacts

Last Updated

6/6/2024