Platform
Company
Immunology & Autoimmune
Reviewed by
Kamran Mir-Moghtadaei
MDCM 2028 · McGill University
This test measures the number of white blood cells in a blood sample taken from the umbilical cord immediately after delivery. White blood cells, also called leukocytes, are immune cells that help protect against infections and respond to inflammation.
The sample is collected from the cord vein after birth and analyzed by an automated cell counter. It provides a snapshot of your baby’s immune status at the moment of delivery, and it can be paired with a blood smear or a differential white cell count if your clinician needs more detail.
Doctors use the cord blood white cell count to help assess a newborn’s risk of infection or inflammation around the time of birth. It is often ordered when there are concerns such as maternal fever, prolonged labor, or other factors that increase the chance of early infection, and it can also reflect stress at delivery.
The result does not stand alone. It is interpreted with the baby’s exam, pregnancy and birth history, and other tests such as a differential count, inflammatory markers, or blood cultures. Together, these pieces guide decisions about observation, antibiotics, or additional testing.
A higher or lower white blood cell count can have many causes. Labor and delivery can temporarily shift counts, and some medicines given to a parent before birth can influence results. Prematurity, growth restriction, or maternal conditions can also play a role. Your clinician will look for patterns and consider whether the result fits with your baby’s overall condition.
If the number is unexpected, your care team may repeat testing after the baby has stabilized or order related tests to clarify whether infection or another issue is present. Ask your clinician what the result means for your baby, what signs to watch for, and whether follow-up testing is planned.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
When the cord blood is collected and how quickly it is processed can affect the white cell count. Delays, clots in the sample, or temperature extremes during transport may lead to misleading results.
Stress from labor or difficult delivery can cause white cells to shift from vessel walls into circulation, temporarily increasing the count. Planned cesarean delivery without labor may show a different pattern.
Medicines given before birth, such as corticosteroids or beta-agonists, can raise the newborn’s white cell count. Other drugs, including some antibiotics, may change how results are interpreted.
Preterm infants often have different baseline white cell patterns than term infants. Immature bone marrow and unique neonatal physiology can influence counts soon after birth.
Conditions such as fever or infection during labor can alter the baby’s white cell response. The count may be part of an evaluation for early-onset infection when these risks are present.
Cord venous versus arterial sampling, dilution with Wharton’s jelly, or partial clotting can affect accuracy. Proper collection technique and prompt analysis help ensure reliable results.
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