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Table 2 Quality assessment tool for birth prevalence estimates

From: Birth prevalence of phenylalanine hydroxylase deficiency: a systematic literature review and meta-analysis

Scoring domain Score
Strong Moderate Weak
Case definitiona The case definition is complete (including both screening positive and confirmed cases) The case definition is partially complete (lacks either the definition of screening positive or of confirmed cases) The case definition is incomplete for both screening positive and confirmed cases
Study setting/source population Mandatory population-wide newborn screening program
General population from a well-defined region and time
Catchment area of a hospital or other medical facility
Hospital or laboratory records or disease registry
Surveys (e.g., to health care providers)
Personal communication
Unclear or not reported
Statistical methods The denominator is the number of newborns screened, and cases in the numerator arise from the population in the denominator
If any quantity is estimated rather than directly measured, estimations are in line with the criteria described here
The denominator is the overall number of births rather than the number screened Cases in the numerator do not arise from the population in the denominator
Unclear or not reported
Precision of prevalence estimateb Half the width of the 95% confidence interval is less than half of the prevalence Half the width of the 95% confidence interval is between half of the prevalence and the prevalencec Half the width of the 95% confidence interval is greater than the prevalence
Confidence interval is not estimable
Diagnostic method used for case confirmationd Tandem mass spectrometry, high-performance liquid chromatography, column chromatography, (rapid) ion exchange chromatography, quantitative amino acid analyzer, positive mutational analysis, or enzymatic assay (including colorimetric, fluorimetric, and ELISA) Guthrie test, bacterial inhibition assay, thin layer or paper chromatography Other methods, or those where urine is used as the assay substrate
Unclear or not reported
  1. aThe case definition was considered complete if the phenylalanine cutoff value was provided
  2. bAdditional file 1 presents the method of calculating the precision of the prevalence estimate
  3. cInclusive of both bounds
  4. dWhen diagnostic methods varied among sites or over time, scoring for the estimate was based on the lowest scoring diagnostic method