Brook listed clinical and laboratory findings for identifying an infant less than 3 months of age who is at low risk for serious bacterial infection. Some of the criteria are the same as given by Dagan et al (Rochester criteria, above).


Selection: Infant < 3 months of age with fever (defined as rectal temperature >= 38°C or >= 100.4°F)


Clinical findings:

(1) born at term (>= 37 weeks gestation) with uncomplicated nursery stay

(2) previously healthy

(3) no toxic manifestations

(4) no focal bacterial infection (except otitis media)


Laboratory findings:

(1) WBC count 5,000 - 15,000 per µL with < 1,500 band per µL or band-to-neutrophil ratio < 2

(2) Normal urinalysis (negative Gram stain on unspun urine, negative leukocyte esterase, negative nitrite, < 5 WBC per high power field)

(3) If diarrhea present, there is no haem and < 5 WBC per high power field on stool smear

(4) If lumbar puncture performed, CSF WBC count < 8 per µL and Gram stain negative

(5) No infiltrate on chest X-ray.


If all of these findings are present, then the infant is considered low risk and can be managed conservatively.



• Premature infants have a high risk of serious bacterial infections during the first month after delivery.

• I assume that the "except otitis media" means that the child would be low risk if that is the only finding present.

• I assume the number of WBC in urine is on a spun urine sediment.

• I think that the WBC count criteria should use AND instead of OR.

• A band to segmented neutrophils ratio of 2 seems to indicate a fairly marked left shift.


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