It is the practice in many newborn nurseries to measure routinely, upon admission, each neonate's blood pressure by cuff oscillometry, blood glucose level by Dextrostix or Chemstrips, and hematocrit value via heel stick. Blood pressure is measured to screen for hypertension or hypotension; blood glucose, for hypoglycemia; and hematocrit, for anemia or polycythemia.
The routine testing of all newborns for a particular disorder before clinical manifestations are evident (universal screening) should result in a positive benefit-cost ratio. The following criteria should be considered in evaluating the benefit-cost ratio for any universal screening.
Incidence. There should be a high enough incidence of the disorder to justify screening for it unless the outcome of the disorder, if left undetected and untreated, would result in such significant morbidity that even with a relatively low incidence the benefit-cost ratio of screening would be positive (eg, phenylketonuria screening).
Methodology. The screening methodology should have a very high sensitivity so that there will be no, or a very low percentage of, subjects reported as being negative who are actually positive. The methodology should also have a high specificity so that there will be relatively few infants who are reported as being positive who are actually negative. The specificity need not be as high as the sensitivity since a true-positive test can be confirmed using a more specific methodology. In addition, the methodology should be relatively simple, cost-effective, accurate, and reproducible.
Natural History. The disorder for which infants are being screened should be a clearly defined entity with a well-described natural history.