Laboratory Evaluation of the Jaundiced Infant of 35 or More Weeks’ Gestation
| Indications | Assessments |
|---|---|
| Jaundice in first 24 h | Measure TcB and/or TSB |
| Jaundice appears excessive for infant’s age | Measure TcB and/or TSB |
| Infant receiving phototherapy or TSB rising rapidly (ie, crossing percentiles [Fig 2]) and unexplained by history and physical examination | Blood type and Coombs’ test, if not obtained with cord blood |
| Complete blood count and smear | |
| Measure direct or conjugated bilirubin | |
| It is an option to perform reticulocyte count, G6PD, and ETCOc, if available | |
| Repeat TSB in 4–24 h depending on infant’s age and TSB level | |
| TSB concentration approaching exchange levels or not responding to phototherapy | Perform reticulocyte count, G6PD, albumin, ETCOc, if available |
| Elevated direct (or conjugated) bilirubin level | Do urinalysis and urine culture. Evaluate for sepsis if indicated by history and physical examination |
| Jaundice present at or beyond age 3 wk, or sick infant | Total and direct (or conjugated) bilirubin level |
| If direct bilirubin elevated, evaluate for causes of cholestasis | |
| Check results of newborn thyroid and galactosemia screen, and evaluate infant for signs or symptoms of hypothyroidism |