Cord blood testing
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.
Cord blood testing can be done to evaluate a newborn's health.
How the Test is Performed
Right 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. The section between the clamps is cut and a blood sample is collected into a specimen tube.
How to Prepare for the Test
No special steps are needed to prepare 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 measure the following in your baby’s blood:
- Bilirubin levels
- Blood culture (if an infection is suspected)
- Blood gases (to evaluate the oxygen, carbon dioxide, and pH levels)
- Blood sugar level
- Blood type and Rh
- Complete blood count (CBC)
- Platelet count
Normal values mean that all items checked 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 means 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:
- Dubin-Johnson syndrome
- Jaundice in the mother
- Mother taking sulfa drugs during pregnancy
- Rh incompatibility
Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
Most hospitals routinely collect cord blood for testing at birth. The process is fairly easy and this is the only time when this type of blood sample can be collected.
You can also decide to bank or donate cord blood at the time of your delivery. 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. There is a charge for the service. Cord blood can also be donated to your local blood bank for use by others as needed for cancer treatment.
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. Pediatrics. 2007;119(1):165-70. PMID: 17200285 www.ncbi.nlm.nih.gov/pubmed/17200285.
American College of Obstetricians and Gynecologists. Umbilical Cord Blood Banking. ACOG Committee Opinion No. 399. Obstet Gynecol. 2008;111:475-7. (Reaffirmed 2012). PMID: 18238991 www.ncbi.nlm.nih.gov/pubmed/18238991.
Carlo WA. The fetus. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 90.