Skip to content

Phbldmv

Published: July 31, 2026Updated: August 16, 2026

This test measures the acidity level (pH) in mixed venous blood, which reflects the overall acid-base balance of body tissues.

Quick summary

{"Measures pH in blood from the pulmonary artery","Reflects tissue oxygenation and metabolic status","Used to assess tissue perfusion and guide treatment in critical patients"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
19213-8
Short code
pH BldMV
Synonyms
pH BldMV
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
not specified
Ref low
7.31
Ref high
7.41
Critical range
7.2 not specified – 7.6 not specified
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

The mixed venous blood pH test measures the acidity level in blood drawn from the pulmonary artery (the main artery carrying blood from the heart to the lungs). This blood represents the average condition of blood returning from all body tissues, providing a comprehensive picture of tissue metabolism and oxygen utilization.

How is the sample collected?

A special catheter called a pulmonary artery catheter (Swan-Ganz catheter) is inserted into a large vein and advanced to the pulmonary artery. Blood is then drawn from this location. This procedure is typically performed in intensive care settings by trained healthcare professionals.

What do the results mean?

Normal mixed venous blood pH typically ranges from 7.32 to 7.42. A pH below 7.32 indicates acidity in body tissues (acidosis), while a pH above 7.42 indicates alkalinity (alkalosis). The result is usually interpreted alongside other values like mixed venous oxygen saturation (SvO2) and venous oxygen content.

Reference range

7.31-7.41not specified

Specimen: serum

No special preparation required; obtained via pulmonary artery catheter

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Why is mixed venous blood pH different from arterial blood pH?
Mixed venous blood has a lower pH than arterial blood because it contains oxygen that has been extracted by body tissues, along with metabolic waste products like carbon dioxide and acids. The normal difference is about 0.03-0.05 pH units.
Is this test painful?
The sample is collected through a catheter that is typically already in place for patient monitoring. You may feel some discomfort from the catheter insertion, but the blood draw itself is usually not painful.
How often is this test performed?
The frequency depends on the patient's condition. In critically ill patients, it may be checked multiple times daily to monitor treatment response and tissue oxygenation status.
  1. 1
    LOINC Code ReferenceSource
  2. 2
    Mixed Venous Oxygen Saturation - StatPearlsSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy