Platform
Company
Complete Blood Count
Review status
Currently under review
Pending specialist review and validation.
The cord blood hematocrit measures the proportion of your newborn’s blood that is made up of red blood cells. It is reported as a fraction of whole blood and reflects how concentrated the red blood cells are. This test uses a small sample collected from the umbilical cord at birth, so it does not require a needle stick for your baby.
Hematocrit helps clinicians understand a newborn’s oxygen-carrying capacity and overall red blood cell status right at delivery. It is often assessed along with other components of a complete blood count to give a quick picture of your baby’s circulation and health.
Cord blood hematocrit helps identify whether a newborn may have too few red blood cells, which can occur with prenatal blood loss, hemolysis, or prematurity, or too many red blood cells, which can be seen with conditions such as maternal diabetes, growth restriction, or delayed cord clamping. Both low and high levels can affect oxygen delivery and blood flow and may relate to risks like jaundice, feeding difficulty, or breathing problems.
Clinicians order this test when there are risk factors during pregnancy or delivery, when a baby shows signs that could be related to red blood cell balance, or as part of routine evaluation when cord blood is already being collected. Results can guide whether simple monitoring is enough or if further testing or treatment is needed.
Your baby’s result is interpreted in the context of gestational age, the type of cord sample collected (arterial or venous), how the delivery went, and other lab findings. A result that is slightly outside the expected range can be temporary, especially right after birth, and may normalize as your baby adapts to life outside the womb.
If the hematocrit is higher than expected, your care team may watch for signs of sluggish circulation, feeding issues, or rising bilirubin, and may recommend hydration or repeat testing. If it is lower than expected, they may look for sources of blood loss, signs of hemolysis or infection, and check for adequate oxygen delivery. Your clinician will explain next steps, which can range from observation to additional labs, depending on your baby’s overall condition.
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.
Hematocrit can differ between umbilical artery and umbilical vein samples. Knowing which vessel was sampled helps clinicians interpret the result appropriately.
Delayed or immediate cord clamping changes how much blood transfers from the placenta to the baby, which can shift hematocrit upward or downward soon after birth.
Diabetes, high blood pressure, smoking, high altitude residence, and placental insufficiency can influence a newborn’s red blood cell concentration.
Preterm birth and growth restriction affect red blood cell production and plasma volume, which can alter hematocrit values in cord blood.
Maternal or fetal intravenous fluids, blood loss during delivery, or in utero transfusions can dilute or concentrate the baby’s blood and affect measured hematocrit.
Improper mixing with anticoagulant, partial clotting, or delays before analysis can change measured hematocrit. Proper collection and prompt testing reduce these effects.
References