Newborn screening for hyperphenylalaninemia on day 5: Is 240 μmol/liter the most appropriate cut-off level?

Clemens, P.; Neumann, Stefan; Wulke, Andreas P.; Burmester, Jens Gunter

doi:10.1016/0091-7435(90)90007-7

Cited by 4 publications

(2 citation statements)

References 29 publications

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“…This cut-off level increases the sensitivity of the screening test and reduces the risk of missing the diagnosis of disorders of the phenylalanine metabolism in subjects with less pronounced phenylalanine circulating levels at the rst investigation. 4 We de ned as normal a phenylalanine concentration on blood spots of 120 mmol/l. All the newborns with phenylalanine concentrations >120 mmol/l were re-tested between the ninth and 16th day of life.…”

Section: Methodsmentioning

confidence: 99%

Neonatal birth parameters of positive newborns at PKU screening as predictors of false-positive and positive results at recall-testing

et al. 2003

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Methods: Phenylalanine concentration was measured with a uorometric multitask plate counterWallac 1420 VICTOR F (Perkin Elmer, Finland) and the uorescent ninhydrine method (EG&G Wallac neonatal phenylalanine kit) using a recall cut-off level >120 mmol/l (2 mg/dl) of phenylalanine on dried blood spots. A multivariate logistic regression analysis was performed to evaluate the predictive role that body parameters (sex, gestational age, parity, weight, length and head circumference) of positive newborns at PKU screening had on false-positive and positive results at recall PKU tests. Results:The risk of false-positive results is higher (~48%) in females than in males. Moreover, for each 100g of body weight reduction, the risk of false positive is around 4.2% higher. The risk of con rmation increased by 39% per week of gestational age. Conclusions:In conclusion, our results suggest that preterm or low-birth-weight neonates recalled at the rst investigation are more likely to be due to false-positives, whereas the risk of con rmation is higher in at-term neonates. By implication, the phenylalanine cut-off value for premature or low-body-weight infants could be higher.

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Section: Methodsmentioning

confidence: 99%

Neonatal birth parameters of positive newborns at PKU screening as predictors of false-positive and positive results at recall-testing

et al. 2003

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“…Therefore, attempts should be given to the selection of optimal cut-off value for the specificity upon insurance of high sensitivity. 20,23 In this study, we included 80,354 neonates who had determination of Phe using fluorometric enzyme methods between June 2017 and December 2018. Among these neonates, the majority (88.38%) had sample collection no later than postpartum day 7, while the minority (11.62%) underwent sample collection at least on postpartum day 8.…”

Section: Discussionmentioning

confidence: 99%

Optimization of Phenylalanine Cut-Off Value in Newborn Screening Based on Blood Sampling Time

Liu

Jin

et al. 2022

Am J Perinatol

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Objective The aim of this study was to optimize the cut-off value of phenylalanine (Phe) for phenylketonuria (PKU) screening in Xinjiang Uygur Autonomous Region based on the time of blood sampling. Study Design In this study, 110,806 neonates born in 91 obstetrics and gynecology hospitals of Xinjiang Uygur Autonomous Region between June 2017 and December 2019 were divided into two groups (i.e., groups 1 and 2) based on the sampling time. The concentration of Phe was determined using fluorimetric method. The optimization of the Phe cut-off value was conducted using the receiver operating characteristic curve from the treating set involving 80,354 neonates. Then, the diagnostic values of the optimized Phe cut-off value were evaluated using validation set involving 30,452 neonates, based on the comparison of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) obtained from conventional cut-off value. Results A range of cut-off values was used for preliminary Phe concentrations in the two groups to analyze the sensitivity, specificity, PPV, and NPV. The optimized cut-off value of Phe in group 1 was 2.0, while that in the group 2 was 2.21. A comparison was given to PPV, NPV, sensitivity, and specificity generated by the optimized cut-off value and the conventional cut-off value, which yielded similar sensitivity, specificity, and PPV, and less recalled number of samples. Conclusion The optimization of cut-off value of Phe based on sampling time is feasible for PKU screening in Xinjiang Uygur Autonomous Region. In addition, the false positive rate was significantly reduced, which may save more efforts in sample recalling process. Key Points

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Das Neugeborenenscreening der ersten Lebenswoche

Clemens¹

2000

Präventivmedizin

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Newborn screening for hyperphenylalaninemia on day 5: Is 240 μmol/liter the most appropriate cut-off level?

Cited by 4 publications

References 29 publications

Neonatal birth parameters of positive newborns at PKU screening as predictors of false-positive and positive results at recall-testing

Neonatal birth parameters of positive newborns at PKU screening as predictors of false-positive and positive results at recall-testing

Optimization of Phenylalanine Cut-Off Value in Newborn Screening Based on Blood Sampling Time

Das Neugeborenenscreening der ersten Lebenswoche

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