Late metabolic acidosis of newborn

This code represents a condition in a newborn characterized by an imbalance in the body's acid-base regulation, specifically an excess of acid, that manifests after the immediate perinatal period. It indicates a metabolic acidosis that develops or is diagnosed later in the neonatal period, rather than being present at birth.

Use this code when documentation specifies metabolic acidosis occurring in a newborn, and the onset is clearly noted as late or occurring after the initial hours of life. This diagnosis is often supported by arterial blood gas (ABG) results showing a low pH and bicarbonate, along with clinical signs of acidosis in a neonate.

• Differentiate carefully between "late" and "fetal" or "intrauterine" metabolic acidosis; the latter is coded to P19.
• Ensure the medical record explicitly states the acidosis is metabolic and not respiratory.
• Look for documentation of the timing of onset to confirm it is not an immediate birth-related event.