The ratio of urinary lactate to urinary creatinine can help identify neonates at risk for developing hypoxic-ischemic encephalopathy. The ratio can also identify the affected infants who are at high risk for adverse outcomes at 1 year of age.


Specimen collection: The urine specimen must be collected within 6 hours of birth.


Chemical analysis:

(1) The authors used NMR spectroscopy to measure parts per million of lactate and creatinine in the urine.

(2) Since a ratio for the number of molecules is used, use of molar data should give comparable results.

(3) Values in US conventional units (mg/dL) SHOULD NOT be used.


ratio urinary lactate to urinary creatinine =

= (urinary lactate) / (urinary creatinine)


Neonatal Group

Ratio for Specimens Collected <= 6 hours After Birth


0.09 +/- 0.02

asphyxia without hypoxic-ischemic encephalopathy

0.19 +/- 0.12

asphyxia with hypoxic-ischemic encephalopathy

16.75 +/- 27.38

hypoxic-ischemic encephalopathy with favorable neurodevelopmental outcome in 1 year

0.63 +/- 1.50

hypoxic-ischemic encephalopathy with adverse neurodevelopmental outcome in 1 year

25.36 +/- 32.02



• Favorable neurolodevelopmental outcome at 1 year: normal neurologic development or mild impairment.

• Adverse neurolodevelopmental outcome at 1 year: death, severe cerebral palsy, developmental delay, blindness, deafness.



• A ratio >= 0.64 for specimens collected <= 6 hours after birth had a sensitivity of 94% and specificity of 100% in identifying infants who developed hypoxic-ischemic encephalopathy.

• Looking at Figure 3, page 333, a rough estimate is that infants with hypoxic-ischemic encephalopathy who have a ratio < 3 tend to have a favorable outcome at 1 year, while those >= 3 tend to have an adverse outcome at 1 year (assuming y axis is LOG10, a horizontal line drawn at 4.5 mm above 1.00 ratio approximates ratio of 3.0)


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