Yale Observation Scale

Assess severity of illness in febrile infants and children aged 3 months to 3 years.

Indication

Assess severity of illness in febrile infants and children aged 3 months to 3 years.

id: cry; label: Quality of cry; type: options; options: value: 1; label: Strong/normal tone OR content/not crying; value: 3; label: Whimpering OR sobbing; value: 5; label: Weak OR moaning OR high-pitched
id: reaction; label: Reaction to parent stimulation; type: options; options: value: 1; label: Cries briefly then stops OR content; value: 3; label: Cries off and on; value: 5; label: Continual cry OR hardly responds
id: state; label: State variation; type: options; options: value: 1; label: Stays awake OR wakes quickly; value: 3; label: Eyes close briefly OR wakes with prolonged stimulation; value: 5; label: Will not rouse OR falls to sleep
id: color; label: Color; type: options; options: value: 1; label: Pink; value: 3; label: Pale extremities OR acrocyanosis; value: 5; label: Pale OR cyanotic OR mottled OR ashen
id: hydration; label: Hydration; type: options; options: value: 1; label: Skin/eyes normal, mucous membranes moist; value: 3; label: Skin/eyes normal, mouth slightly dry; value: 5; label: Skin doughy/tented, dry MM, sunken eyes
id: social; label: Response to social overtures; type: options; options: value: 1; label: Smiles OR alerts (≥2 months); value: 3; label: Brief smile OR alerts briefly; value: 5; label: No smile, anxious/dull/expressionless, no alerting

function(score) { if (score <= 10) return { risk: score + '/30', tier: 'Low risk (<3% serious illness)', action: 'Outpatient management appropriate if well-appearing.', color: 'green' }; if (score <= 15) return { risk: score + '/30', tier: 'Moderate risk', action: 'Careful observation; consider workup based on clinical assessment.', color: 'yellow' }; return { risk: score + '/30', tier: 'High risk (92% serious illness)', action: 'Full sepsis workup, IV access, empiric antibiotics, admission.', color: 'red' }; }

Most useful between 3 months and 3 years — before 3 months all febrile infants need a full sepsis workup regardless of appearance
A score of 6 (all normal) has a NPV of ~97% for serious bacterial infection
Parental concern is a powerful predictor of serious illness — trust it