Lab Test

Venous pH, Whole Blood

pH, Venous

Test Codes





  • Venous pH and/or Ionized Calcium are to be drawn before any tubes, including routine or fungal/AFB blood cultures.
  • Venous pH specimens should ONLY be collected at Hospital Campuses. Specimens should NOT be collected at any other Beaumont Laboratory drawsite, nursing home, or Outreach office.

Specimen Collection Criteria

Preferred Specimen TypesOne non-gel, Dark Green-top Lithium or Sodium Heparin tube, completely filled. Also, a 1 mL or 3 mL plastic syringe containing dry heparin.

Farmington Hills Only: Collect one Sodium Heparin tube

Specimen should be drawn from a free-flowing venous access without a tourniquet in place. The tube top should NOT be removed until the sample is ready to be tested. Place specimen on ice and transport to the Laboratory immediately after collection.

Rejection Criteria

  • Clotted specimens.
  • Specimens not collected or processed as indicated.
  • Specimens received greater than 2 hours from the time of collection.

Inpatient Specimen Preparation

Transport specimen, STAT, on wet ice, to the Laboratory immediately after collection.

In-Lab Processing

Leave specimen on ice and do NOT remove tube top until ready for testing.


Specimen Stability for Testing:

Blood Gas Syringe or Heparinized Tube:

Room Temperature (20-26°C or 68-78.8°F): Specimens must remain on wet ice, maximum of 1 hour.
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Specimens are disposed within 8 hours of testing. 


Canton Chemistry Laboratory
Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory 
Grosse Pointe Chemistry Laboratory
Lenox Chemistry Laboratory 
Royal Oak STAT Laboratory 
Troy Chemistry Laboratory
Taylor Chemistry Laboratory
Trenton Chemistry Laboratory
Wayne Chemistry Laboratory 


Sunday – Saturday, 24 hours a day.
Results available within 15 minutes after receipt in the STAT Laboratory (Royal Oak) or Chemistry Laboratory (Grosse Pointe and Troy).

Reference Range

7.32 – 7.42.

Test Methodology



Knowledge of venous pH aids in evaluating a patient's acid-base status.

Clinical Utility

Venous pH is used to assess acid-base status when a complete arterial blood gas panel is not considered necessary. It is frequently used to monitor patients who are being treated for diabetic ketoacidosis.

A decreased pH is consistent with acidosis and an increased pH is consistent with alkalosis. A normal pH may indicate that the patient has a normal pH or has a mixed acid-base disturbance. Appropriate assessment in the latter case requires arterial blood gas testing.

CPT Codes



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