Neonatal Lab Values
Understanding Neonatal Lab Values in the NICU
🩸 Types of Blood Draws in the NICU
Before we talk lab values, let’s look at how we get them:
Capillary (heel stick): Quick and common, but may not be as accurate for some values (like potassium).
Venous (peripheral venipuncture): More accurate, especially for CBCs and chemistries.
Arterial: Often drawn from arterial lines in critical infants or post-op cardiac babies.
From lines (UVC, UAC, PICC): Helpful for frequent draws, but must be flushed appropriately and checked for hemolysis.
Knowing where the blood came from helps you interpret the result correctly—especially with hemolyzed samples or inconsistencies.
⚖️ Electrolytes: Normals & How to Correct
Electrolytes reflect fluid status, renal function, and can indicate metabolic imbalance. Here are the typical ranges and what to do if they’re abnormal:
Sodium (Na⁺) 135–145 mmol/L ↓: Hyponatremia → fluid overload, SIADH↑: Hypernatremia → dehydration Adjust IV fluids (add/remove NaCl), monitor output
Potassium (K⁺) 3.5–6.0 mmol/L ↓: Risk of arrhythmia↑: Renal issues, hemolysis Supplement cautiously or reduce K in fluids
Calcium (Ca²⁺) 7.0–10.5 mg/dL ↓: Jitteriness, seizures Administer calcium gluconate
Chloride (Cl⁻) 97–110 mmol/L Often reflects acid-base balance Review acid/base & adjust fluids
Bicarb (HCO₃⁻) 18–22 mmol/L Low = metabolic acidosis May need bicarb replacement or treat underlying cause
Always assess the whole picture—are fluids adequate? Is renal output appropriate? Is the infant acidotic?
🧬 CBC: What It Tells You & When to Intervene
A complete blood count (CBC) gives us a snapshot of infection risk, anemia, and clotting ability.
WBC: 9–30 K/μL
↑ = Infection/stress
↓ = Sepsis risk
Hgb/Hct: 14–20 g/dL / 45–65%
↓ = Anemia
↑ = Polycythemia or delayed clamping
Platelets: 150–400 K/μL
↓ = Thrombocytopenia → bleeding risk
💡 Fixes:
Low Hgb → consider transfusion based on symptoms and EPO use.
Low Plts → usually no transfusion unless <50K with bleeding or <30K regardless.
High WBCs? Look at the infant—don’t treat the lab without symptoms.
🌞 Bilirubin: Watching for the Yellow
We monitor bilirubin to prevent kernicterus, a rare but serious type of brain damage.
Total serum bilirubin (TSB): Use the infant’s age in hours and risk factors on the Bhutani Nomogram or your unit’s phototherapy guideline.
Risk Factors: Hemolysis, prematurity, bruising, Asian descent, poor feeding.
🔆 Management:
Phototherapy is the mainstay treatment.
Monitor output and hydration.
Exchange transfusion in rare cases for dangerously high levels.
🍬 Blood Sugar: Small Number, Big Impact
Glucose stability is vital in the first days of life, especially in preemies, IUGR, LGA, IDM babies.
Glucose ranges typically 45-120
If low, treat with sugar but also consider why it may be low
If high, lower GIR and consider if this is a one off high or if the lab is trending up
🍼 Fixes:
Early feeding (preferably colostrum or breastmilk)
D10W bolus or infusion
Glucagon in emergent situations
Persistent low sugars can lead to seizures or poor neurodevelopment—act early!
❤️ Pain Management During Labs
Even tiny pokes can hurt. Always consider non-pharmacologic interventions:
Sucrose + pacifier
Swaddling & containment
Skin-to-skin when possible
Breastfeeding during procedures (if stable)
Pain control is a neuroprotective strategy—especially in preemies.
👪 Parent Education: Turning Labs into Language
To families, all the numbers can feel overwhelming. Help by explaining:
Why we draw labs (“We’re checking how hydrated your baby is” or “We’re watching for signs of jaundice”)
What’s normal vs. what’s concerning
What treatment means—“the blue lights help break down the jaundice” is easier to understand than “phototherapy”
Be honest, reassuring, and use visual aids or handouts if your unit has them. This builds trust and transparency.
Final Thoughts
Lab results are one piece of the puzzle—but understanding their clinical context is what makes you a strong NICU nurse. As you grow from novice to expert, your ability to interpret and act on lab trends will sharpen—and your patients will benefit from your insight.
