This Yale observation scale for infant fever calculator evaluates the febrile status in the pediatric setting in children with or without urgent presentation. Below the form there is in depth information on the scale and instructions on how to interpret the numeric score.

Quality of cry

Reaction to parents

State variation



Social response

How does this Yale observation scale for infant fever calculator work?

This is a health tool often used in pediatric departments and in the ER to predict the likeliness of a serious infection, often an occult bacteremia.

The Yale observation scale for infant fever calculator should be used in the assessment of the febrile child aged 3 to 36 months and consists of 6 criteria observed in the appearance and behavior of the infant. These are described in the following lines:

■ Quality of cry – is evaluated as either inexistent or very strong, a whimper or sob or a moaning, weak cry.

■ Reaction to parents – ranges from brief cry or content, on and off crying or persistent crying.

■ State variation – whether the infant awakens quickly, whether they present difficulty at awakening or that they don’t respond to arousal and fall asleep.

■ Color – checks if the appearance of the skin is pink, acrocyanotic or pale, cyanotic or mottled.

■ Hydration – evaluates the moistness of eyes, skin and mucus membranes, whether the mouth is slightly dry or the eyes are sunken, although not influenced by the feeding method.

■ Social response – varies from alert and/or smiling, alert with a brief smile or no smile, anxiety presence or dullness.

Feverish children assessments try to take into account physical examination findings in ill appearing children with fever greater than 101.3 F (38.5 C). Re-evaluation is required if the febrile state persists more than 48 hours.

The most common toxic findings suggestive of occult bacteremia include: temperature with positive blood cultures and WBC count significant with infection.

Score interpretation

The score aims at quantifying the toxic appearance in infants at presentation and each of the above criteria is described in three stages, the first stage is awarded 1 point, the second stage in gravity is awarded 3 points while the most severe stage of symptoms for that criterion is awarded 5 points.

Therefore the total score in the Yale scale for febrile child ranges from 0 to 30 and the comments for the scale intervals are detailed below:

■ Scores below 10 should be regarded with caution further but at the present moment don’t carry a serious threat to the health of the infant.

■ Scores of 10 are considered to have a serious illness incidence of 2.7%. In scores between 11 and 15 the incidence rate grows at 26% while in all scores over 16, the serious illness risk soars to up to 92.3%.

Other criteria scales for feverish infant assessment include the Rochester criteria for new born to infants of 60 days, the Philadelphia criteria for febrile infants 29 – 60 days and the Boston criteria 28 – 89 days.

Sepsis in infants and children

Sepsis is characterized mainly as the immune system response to an infection that determines the body to fight against own tissues and organs in order to combat the infection.

Neonatal sepsis is the blood infection occurring in infants younger than 3 months with an early onset in the first week of life.

Pediatric sepsis on the other hand can occur later on and is due to an infection coming on a decreased immune protection setting as young children don’t have yet their own skilled set of antibodies to fight off infection properly.

Urinary, lung infections or similar types of infection can get into the blood stream and thus the virus or bacteria will have to be fought off with antibiotics.

The signs of sepsis are divided by their areas of influence in the following table:

Fever temperature > 101.3 F (38.5 C)
Hypothermia temperature < 96.8 F (36.0 C)
Tachycardia heart rate over age based normal value
Tachypnea respiratory rate over age based normal value
Hypotension systolic blood pressure with high vascular resistance
Vasoconstriction peripheral, cold extremities, cold shock
Appearance irritable, lethargic, sleep and feeding disturbances
Skin petechiae, purpura, paleness


1) McCarthy PL, Sharpe MR, Spiesel SZ, Dolan TF, Forsyth BW, DeWitt TG, Fink HD, Baron MA, Cicchetti DV. (1982) Observation scales to identify serious illness in febrile children. Pediatrics; 70(5):802-9.

2) McCarthy PL, Lembo RM, Baron MA, Fink HD, Cicchetti DV. (1985) Predictive value of abnormal physical examination findings in ill-appearing and well-appearing febrile children. Pediatrics; 76(2):167-71.

3) McCarthy PL, Lembo RM, Fink HD, Baron MA, Cicchetti DV. (1987) Observation, history, and physical examination in diagnosis of serious illnesses in febrile children less than or equal to 24 months. J Pediatr; 110(1):26-30.

4) Bang A, Chaturvedi P. (2009) Yale Observation Scale for prediction of bacteremia in febrile children. Indian J Pediatr; 76(6):599-604.

29 Nov, 2015