Baseexcessstdbldcoacalcscnc

Published: August 9, 2026Updated: August 16, 2026

This test measures the base excess in arterial cord blood to evaluate the baby's acid-base balance at birth, helping doctors assess if the baby experienced oxygen deprivation during labor and delivery.

Quick summary

{"Base excess measures the amount of acid or base in the baby's blood at birth","A normal result typically ranges from -10 to +5 mmol/L","Negative values may indicate the baby experienced stress or lack of oxygen during labor","This test is often performed when there are signs of fetal distress","Results help doctors determine if the newborn needs additional monitoring or care"}

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

Key facts at a glance

LOINC: 97773-6
Short code: Base excess std BldCoA Calc-sCnc
Synonyms: Base excess std BldCoA Calc-sCnc
Category: chemistry
Sample: whole-blood
Container: Lavender-top (EDTA)
Units: N/A
Fasting: false
Population: adult
Sex: all
Age range: 18–65 years
Method: calculated
Specimen volume: 3 mL
Stability: Room temperature: 4h, Refrigerated: 24h
Hemolysis max: 0
Lipemia max: 0
Icterus max: 0
TAT: 4–24 hours
Order: routine

What is this test?

The base excess standard test measures the amount of excess base (buffer) in the baby's arterial cord blood. Arterial cord blood is taken from the umbilical artery immediately after birth. This test is part of cord blood gas analysis, which evaluates the baby's metabolic condition at the moment of birth. Base excess is a calculated value that indicates whether the baby's blood has too much acid (negative value) or too much base (positive value) compared to normal levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Why is arterial cord blood used instead of venous cord blood?

Arterial cord blood better reflects the baby's own blood composition and metabolic status, while venous cord blood may be affected by maternal blood. The umbilical artery carries blood away from the baby, so arterial cord blood gives a more accurate picture of the baby's condition at birth.

What does a negative base excess mean?

A negative base excess indicates metabolic acidosis, meaning the baby's blood is more acidic than normal. This can occur when the baby doesn't receive enough oxygen during labor, causing the body to produce lactic acid. The severity of the negative value helps doctors assess how significant the oxygen deprivation was.

Is this test painful for the baby?

No, the blood is taken from the umbilical cord immediately after birth, before the cord is clamped and cut. This is done after the baby is delivered and does not cause any pain to the newborn.

Will my baby need special care if the base excess is abnormal?

If the base excess shows significant abnormalities, your healthcare team will closely monitor your baby for any signs of distress. This may include additional observations, blood tests, or specialized care in the neonatal unit depending on the results and the baby's overall condition.

Sources

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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