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 the Grosse Pointe, Royal Oak, Troy, or Farmington Hills Hospital Campuses. Specimens should NOT be collected at any other Beaumont Laboratory drawsite, nursing home, or Outreach office.

Specimen Collection Criteria

Collect: One non-gel, Dark Green-top Lithium or Sodium Heparin tube, completely filled.
Also acceptable: 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.
Also acceptable: A 1 mL or 3 mL plastic syringe containing dry heparin.
Farmington Hills Only: Collect one Sodium Heparin tube.

In-Lab Processing

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


Specimen Stability for Testing:

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.


Grosse Pointe Chemistry Laboratory
Royal Oak STAT Laboratory
Troy Chemistry Laboratory
Farmington Hills 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



Last Updated


Microtainer® and Vacutainer® are registered trademarks of Becton, Dickinson and Company.
UroVysion® is a registered trademark of Abbott Laboratories. ThinPrep® is a registered trademark of Hologic, Incorporated.


This directory currently reflects information only for specimens collected and/or processed at the
Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.