Please note: In 2003, the CTF updated its Grades of Recommendations to include an "I Recommendation" for situations where insufficient evidence exists to allow a recommendation to be made. (Formerly, these situations were captured under a "C Recommendation".) This change is not retroactive, and all "C Recommendations" made prior to 2003 have not been reevaluated in light of the new "I" recommendation grade. For a discussion of these recommendation grades, please link to the 2003 article in the Canadian Medical Association Journal here.
| MANEUVER | EFFECTIVENESS | LEVEL OF EVIDENCE <REF> | RECOMMENDATION |
| Newborn screening by automated blood phenylalanine prior to discharge from the nursery. Infants tested before 24 hours of age should receive a repeat screening test between 2-7 days of age. | Guthrie test has high sensitivity and an acceptable false-positive rate; fluorometric assays have a higher sensitivity. | Case series <5,6> (III) | There is good evidence for newborn screening for PKU. (A) |
| False negative rates from 2-31% have been reported for testing within the first 24 hours after birth. | Case series <5,7,8> (III) | ||
| Burden of suffering is great and dietary treatment with low phenylalanine diet has had a dramatic effect on morbidity (pre-treatment era mean intelligence quotient (IQ) of £ 40 to a post-treatment era mean IQ of ³ 100). | Dramatic differences between times and places <6,12-18> (I); case series <2> (III) | ||
| Screening pregnant women by automated blood phenylalanine for phenylketonuria (PKU) to prevent intrauterine damage to the fetus. | The incidence of undiagnosed maternal PKU is low. | Case series <1,11> (III) | There is no evidence to recommend for or against screening pregnant women for undiagnosed PKU. (C) |
| In women with undiagnosed mild PKU, fetus may be damaged by excess dietary phenylalanine. | Expert opinion <4,10> (III) | ||
| No universal maternal PKU screening program has been implemented or evaluated. | |||
| Some investigators have not found maternal diet beneficial Low protein diet required may have negative effects on fetus. | Cohort <22> (II-2); case series <4,24-28> (III) | ||
| Diet may need to be started prior to conception. | Expert opinion <1,3,22,23,26-28> (III) |
Link to Full Text of this review
Link to Structured Abstract of this review
Link to Selected References list of this review
Reprinted in modified format by the Canadian
Task Force on Preventive Health Care
with permission.
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© 1994 Minister of Supply and Services Canada.
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Last modified March 27, 1998.
