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Kramer Scale Calculator (Newborn Jaundice by Body Zone)

Estimate a newborn’s bilirubin range from how far down the body the yellow color has spread (Kramer zones 1–5) and see when a skin or blood bilirubin test is needed.

Lowest body area that looks yellow

Did the jaundice appear in the first 24 hours?

Was the baby born before 37 weeks?

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How it works

Kramer zone → approximate total serum bilirubin: zone 1 4–8 mg/dL, zone 2 5–12, zone 3 8–16, zone 4 11–18, zone 5 > 15 · µmol/L = mg/dL × 17.1

Jaundice in newborns spreads from the head toward the feet as bilirubin rises. Kramer (1969) divided the body into five zones — head and neck, upper trunk, lower trunk and thighs, arms and lower legs, and palms and soles — and showed that each zone corresponds to an increasing range of serum bilirubin. The overlap between zones is large and visual estimation is unreliable in dark skin, under artificial light and after phototherapy, so the AAP 2022 guideline asks for a transcutaneous or serum bilirubin measurement in any jaundiced newborn, and urgently when jaundice appears in the first 24 hours.

Worked example

A term baby whose yellow color reaches the knees (Kramer zone 3), first seen after 24 hours: the estimated bilirubin is 8–16 mg/dL (137–274 µmol/L), so measure bilirubin (skin or blood test) today.

Sources: Kramer LI (1969) Advancement of dermal icterus in the jaundiced newborn. Am J Dis Child 118(3):454–458 · Kemper AR et al. (2022) AAP Clinical Practice Guideline Revision: Management of hyperbilirubinemia in the newborn infant 35 or more weeks of gestation. Pediatrics 150(3):e2022058859

Frequently asked questions

What are the Kramer zones?

Five body areas used to estimate newborn jaundice: zone 1 head and neck, zone 2 upper trunk to the navel, zone 3 lower trunk and thighs to the knees, zone 4 arms and lower legs, and zone 5 palms and soles.

Is the Kramer scale accurate?

Only roughly. Each zone covers a wide bilirubin range and visual assessment can underestimate levels, especially in babies with darker skin. It is a screening aid; treatment decisions need a measured bilirubin plotted against the baby’s age in hours.

When is newborn jaundice dangerous?

Jaundice in the first 24 hours, yellow palms and soles, a very sleepy or poorly feeding baby, pale stools or dark urine, or jaundice lasting beyond 2 weeks (3 weeks in preterm babies) need prompt medical review.

Does sunlight treat jaundice?

No. Direct sunlight is not a safe or reliable treatment and can cause sunburn or overheating. Effective treatment is phototherapy with special blue light in a health facility, guided by bilirubin levels.

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