Compute the newborn Apgar score by the five-sign rubric

Handed a description of a newborn a minute after delivery, the base model tends to eyeball a number. Two failures dominate: it treats blue hands and feet on an otherwise pink baby as full color credit (it is not), and it rounds a heart rate in the 90s up to full credit (it is not). It also silently drops a sign it was not sure how to score, so a five-sign total comes back built from four. The score is not a gestalt impression — it is a sum of five fixed sub-scores, and each one has a hard rule.

What this computes

The Apgar score rates a newborn's condition as an integer from 0 to 10. You score five signs, each 0, 1, or 2, and add them. The signs are Appearance (color), Pulse (heart rate), Grimace (reflex irritability), Activity (muscle tone), and Respiration (breathing effort). Source: Apgar V. (1953), A proposal for a new method of evaluation of the newborn infant, Curr Res Anesth Analg 32:260. This is the standard clinical rubric, US/international, as of 2026-07; it has been stable since introduction.

The complete rubric — score every sign, then sum

Score all five. A missing or unmentioned sign is scored 0, not skipped.

Appearance (skin color)

• 0 — blue or pale over the whole body.
• 1 — body pink but the extremities (hands and feet) are blue. This is acrocyanosis, and it is worth exactly 1, never 2.
• 2 — pink everywhere, extremities included.

Pulse (heart rate)

• 0 — no heartbeat detectable.
• 1 — a heart rate below 100 beats per minute (anything from 1 up to 99).
• 2 — a heart rate of 100 or more beats per minute (100 itself scores 2).

Grimace (reflex irritability to stimulation)

• 0 — no response to a flick of the sole or to suctioning.
• 1 — a grimace, a facial move, or a feeble cry only.
• 2 — a vigorous cry, cough, sneeze, or active pull-away.

Activity (muscle tone)

• 0 — limp, flaccid, no tone.
• 1 — some flexion of the arms or legs.
• 2 — active motion, limbs well flexed and resisting.

Respiration (breathing effort)

• 0 — not breathing; apneic.
• 1 — slow, irregular, gasping, or a weak cry.
• 2 — a strong, regular, lusty cry.

Total = Appearance + Pulse + Grimace + Activity + Respiration. Report the integer only.

The two rules the base model breaks

1. Acrocyanosis is a 1, not a 2. A newborn whose trunk is pink but whose hands and feet stay blue has scored 1 point for color, even when everything else is perfect. A baby cannot reach 10 while its extremities are still blue — the ceiling with acrocyanosis is 9.
2. The pulse cutoff is a hard 100. Below 100 is 1 point; 100 or above is 2. A rate of 98 or 99 does not round up. Only "absent" scores 0 — a slow-but-present pulse is always at least 1.

Worked examples (BEFORE the fix -> AFTER)

Acrocyanosis ceiling. Trunk pink, hands and feet still dusky; rate 132; screams when the foot is flicked; limbs well flexed and thrashing; a loud cry.

• BEFORE: "looks great -> 10."
• AFTER: color = 1 (extremities blue), pulse = 2, grimace = 2, tone = 2, respiration = 2 -> 9.

Heart rate in the 90s. Pink all over; rate charted at 94; vigorous cry to suction; active motion; strong cry.

• BEFORE: "94 is basically fine -> 2 for pulse -> 10."
• AFTER: pulse = 1 (below 100); all others = 2 -> 9.

A dropped sign. Pale throughout; no heartbeat found; a weak grimace to the sole flick; some flexion of the legs; feeble irregular gasps.

• BEFORE: scores four signs, forgets pulse -> "4."
• AFTER: color = 0, pulse = 0 (absent), grimace = 1, tone = 1, respiration = 1 -> 3. The absent pulse is a scored 0, not an omission.

One sign absent, the rest strong. Fully pink; rate 158; coughs and cries hard; active and well flexed; but not breathing at all.

• BEFORE: "healthy pink active baby -> 9 or 10."
• AFTER: respiration = 0 (apneic) drags an otherwise-8 total down; color 2 + pulse 2 + grimace 2 + tone 2 + respiration 0 -> 8.

Edge cases

• Exactly 100 bpm scores 2 for pulse — the cutoff is inclusive at 100.
• Present but very slow pulse (e.g. 55 bpm) scores 1, never 0. Zero is reserved for a truly absent heartbeat.
• "Cyanotic" or "dusky all over" means the whole body is blue -> color 0. Reserve color 1 for the specific pattern of a pink trunk with blue extremities only.
• A weak/feeble cry is ambiguous by design: it earns 1 for grimace (a feeble cry, not vigorous) and 1 for respiration (a weak cry, not a strong one). Score both signs from the same weak cry.
• A strong cry simultaneously supports grimace = 2 (vigorous vocal response) and respiration = 2 (lusty breathing) — do not double-count it as extra points, but do credit each of the two distinct signs.
• Some flexion vs. active motion: "some flexion of the extremities" is tone 1; "active motion" or "resisting extension" is tone 2. Flaccid/limp is 0.

Do / Don't

• Do score all five signs even when the report is terse; an unmentioned sign is 0, and say so.
• Don't give color 2 whenever the word "pink" appears — check whether the hands and feet are still blue first.
• Do treat 100 bpm as the inclusive boundary (>= 100 -> 2).
• Don't round a heart rate in the 90s up to 2; below 100 is always 1.
• Do return a single integer in 0, 10].
• Don't invent a "half point" or report a sub-score breakdown unless asked — the deliverable is the total.

Common mistakes

• Counting acrocyanosis (pink body, blue extremities) as full color credit -> inflates the total by 1.
• Rounding a heart rate of 92-99 up to 2 -> inflates by 1.
• Scoring a present-but-slow pulse as 0 instead of 1 -> deflates by 1.
• Silently omitting a sign the reporter did not mention, so the sum is built from four signs -> usually deflates.
• Reading "not breathing" or "apneic" as anything but respiration 0.

Output

Return the total as a JSON object keyed apgar with an integer value, e.g. {"apgar": 9}. No sub-scores, no prose, unless the caller asks for the breakdown.

Deterministic grading

scripts/grading_spec.json holds the correct integer for each benchmark newborn, and scripts/grade.py parses the answered apgar value and compares it exactly. See the eval suite.