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Cord blood testing

Definition

Cord blood refers to a sample of blood collected from the umbilical cord when a baby is born. The umbilical cord is the cord connecting the baby to the mother's womb.

This article focuses on cord blood testing done to evaluate a newborn's health.

How the test is performed

Immediately after the birth of your baby, the umbilical cord is clamped and cut. If cord blood is to be drawn, another clamp is placed 8 to 10 inches away from the first, then the isolated section is cut and a blood sample is collected into a specimen tube.

How to prepare for the test

No special preparation is necessary for this test.

How the test will feel

You will not feel anything beyond the normal birthing process.

Why the test is performed

Cord blood testing is done to determine the following:

  • levelsBilirubin
  • (if an infection is suspected)Blood culture
  • Blood gases, to evaluate the oxygen, carbon dioxide, and pH levels
  • Blood sugar level
  • and RhBlood type
  • Complete blood count (CBC )
  • Platelet count

Normal Values

Normal values mean that all items evaluated are within normal range.

What abnormal results mean

A low pH (less than 7.04 to 7.10) means there are higher levels of acids in the baby's blood. This might occur when the baby does not get enough oxygen during labor. One reason for this could be that the umbilical cord was compressed during labor or delivery.

A blood culture that is positive for bacteria measn you have a blood infection (septicemia).

High levels of blood sugar (glucose) in the cord blood may be found if the mother has diabetes. The newborn will be watched for hypoglycemia (low blood sugar) after delivery.

High levels of bilirubin could be due to infections that the baby gets before birth, including:

Other possible causes include:

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

Special considerations

Most hospitals routinely collect cord blood for testing at birth, since it is relatively convenient and the only time possible to collect such blood. Besides cord blood testing, cord blood can be used to treat certain types of bone marrow-related cancers. Some parents may choose to save (bank) their child's cord blood for this and other, future medical purposes.

Cord blood banking for personal use is done by private companies, which charge for the service. Cord blood can also be donated to your local blood bank for use by others as needed to treat leukemia and other cancers.

References

American Academy of Pediatrics Section on Hematology/Oncology, American Academy of Pediatrics Section on Allergy/Immunology, Lubin BH, Shearer WT. Cord blood banking for potential future transplantation. 2007;119(1):165-170.  

Carlo WA. The fetus. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. . 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 90.

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    Encyclopedia content is provided as information only and not intended to replace the advice and instruction from your personal physician.