Evaluation of the Dutch neonatal screening for congenital adrenal hyperplasia

Neonatal reference intervals for serum steroid hormone concentrations measured by LC-MS/MS

OBJECTIVES

Congenital adrenal hyperplasia (CAH) is a rare, inherited disorder of adrenal steroid synthesis. In many countries it is part of the neonatal screening program enabling early diagnosis and treatment. In case of an abnormal neonatal screening result or when other differences of sexual development (DSD) are suspected, measurement of serum steroid hormones using liquid chromatography coupled to mass spectrometry (LC-MS/MS) is needed for further diagnosis. However, reliable age- and sex-specific reference intervals (RIs) for serum steroid hormones during the neonatal period are missing. We therefore aimed to establish LC-MS/MS based RIs for serum steroid hormones in neonates.

METHODS

Serum was obtained from healthy term neonates at two time points: 130 samples at day 3-8 (T1, time of the neonatal screening) and 126 samples at day 13-15 (T2, two weeks old). Concentrations of cortisol, cortisone, corticosterone, 11-deoxycortisol, 21-deoxycortisol, 11-deoxycorticosterone, testosterone, androstenedione, and 17-hydroxyprogesterone (17-OHP) were measured using LC-MS/MS.

RESULTS

RIs (in nmol/L) were established for T1 and T2: cortisone (19.3-215;18.0-212), cortisol (10.0-407;8.4-446), corticosterone (<31;<50), 11-deoxycortisol (0.73-4.6;0.70-3.6), 17-OHP (<4.9;<5.1), androstenedione (0.3-1.8;0.3-2.7), 11-deoxycorticosterone (<0.2;<0.2), and 21-deoxycortisol (<1;<1), respectively. Testosterone differed between boys and girls: RIs at T1 and T2 for boys were 0.27-4.3 and 0.63-13.9, and for girls<0.30 and <0.47, respectively.

CONCLUSIONS

We established LC-MS/MS based RIs for cortisol, cortisone, corticosterone, 11-deoxycortisol, 21-deoxycortisol, 11-deoxycorticosterone, testosterone, androstenedione, and 17-OHP in neonates in the first and second week of life.

Current Status of Newborn Bloodspot Screening Worldwide 2024: A Comprehensive Review of Recent Activities (2020-2023)

Newborn bloodspot screening (NBS) began in the early 1960s based on the work of Dr. Robert "Bob" Guthrie in Buffalo, NY, USA. His development of a screening test for phenylketonuria on blood absorbed onto a special filter paper and transported to a remote testing laboratory began it all. Expansion of NBS to large numbers of asymptomatic congenital conditions flourishes in many settings while it has not yet been realized in others. The need for NBS as an efficient and effective public health prevention strategy that contributes to lowered morbidity and mortality wherever it is sustained is well known in the medical field but not necessarily by political policy makers. Acknowledging the value of national NBS reports published in 2007, the authors collaborated to create a worldwide NBS update in 2015. In a continuing attempt to review the progress of NBS globally, and to move towards a more harmonized and equitable screening system, we have updated our 2015 report with information available at the beginning of 2024. Reports on sub-Saharan Africa and the Caribbean, missing in 2015, have been included. Tables popular in the previous report have been updated with an eye towards harmonized comparisons. To emphasize areas needing attention globally, we have used regional tables containing similar listings of conditions screened, numbers of screening laboratories, and time at which specimen collection is recommended. Discussions are limited to bloodspot screening.

Androgen Excess and Deficiency: Analytical and Diagnostic Approaches

BACKGROUND

Androgens are synthesized from cholesterol through sequential conversions by enzymes in the adrenal glands and gonads. Serum levels of androgens change during the different phases of life and regulate important developmental and maturational processes. Androgen excess or deficiency can therefore present at various ages in various ways.

CONTENT

The diagnostic approach for atypical genitalia, premature pubarche, delayed pubertal onset or progression, and hirsutism or virilization, including measurement of androgens (testosterone, androstenedione, 17-OHprogesterone, dehydroepiandrosterone, and dihydrotestosterone) is discussed in the current review. Androgens can be measured in serum, saliva, urine, or dried blood spots. Techniques to measure androgens, including immunoassays and LC-MS, have their own advantages and pitfalls. In addition, pre- and postanalytical issues are important when measuring androgens.

SUMMARY

During clinical interpretation of androgen measurements, it is important to take preanalytical circumstances, such as time of blood withdrawal, into account. As immunoassays have major drawbacks, especially in samples from women and neonates, concentrations measured using these assays should be interpreted with care. Reference intervals can only be used in relation to the measurement technique and the standardization of the assay. In the near future, new androgens will probably be added to the current repertoire to further improve the diagnosis and follow-up of androgen excess or deficiency.

Landscape of Adrenal Tumours in Patients with Congenital Adrenal Hyperplasia

Our aim is to update the topic of adrenal tumours (ATs) in congenital adrenal hyperplasia (CAH) based on a multidisciplinary, clinical perspective via an endocrine approach. This narrative review is based on a PubMed search of full-length, English articles between January 2014 and July 2023. We included 52 original papers: 9 studies, 8 case series, and 35 single case reports. Firstly, we introduce a case-based analysis of 59 CAH-ATs cases with four types of enzymatic defects (CYP21A2, CYP17A1, CYP17B1, and HSD3B2). Secondarily, we analysed prevalence studies; their sample size varied from 53 to 26,000 individuals. AT prevalence among CAH was of 13.3-20%. CAH prevalence among individuals with previous imaging diagnosis of AT was of 0.3-3.6%. Overall, this 10-year, sample-based analysis represents one of the most complex studies in the area of CAH-ATs so far. These masses should be taken into consideration. They may reach impressive sizes of up to 30-40 cm, with compressive effects. Adrenalectomy was chosen based on an individual multidisciplinary decision. Many tumours are detected in subjects with a poor disease control, or they represent the first step toward CAH identification. We noted a left lateralization with a less clear pathogenic explanation. The most frequent tumour remains myelolipoma. The risk of adrenocortical carcinoma should not be overlooked. Noting the increasing prevalence of adrenal incidentalomas, CAH testing might be indicated to identify non-classical forms of CAH.

Epidemiology and diagnostic trends of congenital adrenal hyperplasia in Denmark: a retrospective, population-based study

Background

The prevalence of newborns with congenital adrenal hyperplasia (CAH) detected by neonatal screening is well-described, but data including patients diagnosed later in life are extremely limited. This study aimed to describe diagnostic trends for all patients with CAH in Denmark.

Methods

A nationwide population-based registry study including medical record review.

Findings

We identified 462 patients (290 females) with any form of CAH. The prevalence of CAH combined was 15.1 (95% confidence interval [CI]: 12.3-16.1) and 9.0 (CI: 7.6-10.4) per 100,000 newborn females and males. There was a prevalence of salt-wasting (SW), simple-virilizing (SV), and non-classic (NC) CAH due to 21-hydroxylase deficiency of: SW-CAH: 6.4 (CI: 5.3-7.6) and 5.6 (CI: 4.6-6.8); SV-CAH: 2.0 (CI: 1.4-2.8) and 1.6 (CI: 1.0-2.7); and NC-CAH: 5.5 (CI: 4.4-6.9) and 2.5 (CI: 1.7-3.7) per 100,000 newborn females and males, respectively. Diagnosis of NC-CAH increased significantly during the course of the study. There was a female preponderance for SV-CAH (ratio: 1.8) and NC-CAH (ratio: 3.2). Median age at diagnosis, females and males respectively: SW-CAH: 4 (interquartile range [IQR]: 0-11) and 14 (IQR: 8-24) days, SV-CAH: 3.1 (IQR: 1.2-6.6) and 4.8 (IQR: 3.2-6.9) years, and NC-CAH: 15.5 (IQR: 7.9-22.5) and 9.4 (IQR: 7.2-23.2) years.

Interpretation

The combined prevalence of CAH was 15.1 and 9.0 per 100,000 newborn females and males, respectively. The female preponderance was primarily due to diagnosis of more females than males with NC-CAH.

Funding

International Fund of Congenital Adrenal Hyperplasia, Health Research Fund of Central Denmark Region, Aase and Einar Danielsen Fund, and "Fonden til Lægevidenskabens Fremme".

Congenital Adrenal Hyperplasia-Current Insights in Pathophysiology, Diagnostics, and Management

Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders affecting cortisol biosynthesis. Reduced activity of an enzyme required for cortisol production leads to chronic overstimulation of the adrenal cortex and accumulation of precursors proximal to the blocked enzymatic step. The most common form of CAH is caused by steroid 21-hydroxylase deficiency due to mutations in CYP21A2. Since the last publication summarizing CAH in Endocrine Reviews in 2000, there have been numerous new developments. These include more detailed understanding of steroidogenic pathways, refinements in neonatal screening, improved diagnostic measurements utilizing chromatography and mass spectrometry coupled with steroid profiling, and improved genotyping methods. Clinical trials of alternative medications and modes of delivery have been recently completed or are under way. Genetic and cell-based treatments are being explored. A large body of data concerning long-term outcomes in patients affected by CAH, including psychosexual well-being, has been enhanced by the establishment of disease registries. This review provides the reader with current insights in CAH with special attention to these new developments.

Second-tier Testing for 21-Hydroxylase Deficiency in the Netherlands: A Newborn Screening Pilot Study

CONTEXT

Newborn screening (NBS) for classic congenital adrenal hyperplasia (CAH) consists of 17-hydroxyprogesterone (17-OHP) measurement with gestational age-adjusted cutoffs. A second heel puncture (HP) is performed in newborns with inconclusive results to reduce false positives.

OBJECTIVE

We assessed the accuracy and turnaround time of the current CAH NBS algorithm in comparison with alternative algorithms by performing a second-tier 21-deoxycortisol (21-DF) pilot study.

METHODS

Dried blood spots (DBS) of newborns with inconclusive and positive 17-OHP (immunoassay) first HP results were sent from regional NBS laboratories to the Amsterdam UMC Endocrine Laboratory. In 2017-2019, 21-DF concentrations were analyzed by LC-MS/MS in parallel with routine NBS. Diagnoses were confirmed by mutation analysis.

RESULTS

A total of 328 DBS were analyzed; 37 newborns had confirmed classic CAH, 33 were false-positive and 258 were categorized as negative in the second HP following the current algorithm. With second-tier testing, all 37 confirmed CAH had elevated 21-DF, while all 33 false positives and 253/258 second-HP negatives had undetectable 21-DF. The elevated 21-DF of the other 5 newborns may be NBS false negatives or second-tier false positives. Adding the second-tier results to inconclusive first HPs reduced the number of false positives to 11 and prevented all 286 second HPs. Adding the second tier to both positive and inconclusive first HPs eliminated all false positives but delayed referral for 31 CAH patients (1-4 days).

CONCLUSION

Application of the second-tier 21-DF measurement to inconclusive first HPs improved our CAH NBS by reducing false positives, abolishing the second HP, and thereby shortening referral time.

Impact of Newborn Screening on Clinical Presentation of Congenital Adrenal Hyperplasia

Background and Objectives: The main reason for Newborn screening (NBS) for congenital adrenal hyperplasia (CAH) is to prevent adrenal insufficiency that can lead to life-threatening conditions. On the other hand, screening programs are not always sensitive and effective enough to detect the disease. We aimed to evaluate impact of the national NBS on the clinical presentation of patients with CAH in Lithuania. Materials and Methods: A retrospective study was performed on data of 88 patients with CAH from 1989 to 2020. Patients with confirmed CAH were divided into two groups: (1) 75 patients diagnosed before NBS: 52 cases with salt-wasting (SW), 21 with simple virilising (SV) and two with non-classical (NC) form; (2) 13 patients diagnosed with NBS: 12 cases with SW and 1 case with SV form. For the evaluation of NBS effectiveness, data of only male infants with salt-wasting CAH were analysed (n = 36, 25 unscreened and nine screened). Data on gestational age, birth weight, weight, symptoms, and laboratory tests (serum potassium and sodium levels) on the day of diagnosis, were analysed. Results: A total of 158,486 neonates were screened for CAH from 2015 to 2020 in Lithuania and CAH was confirmed in 13 patients (12 SW, one–SV form), no false negative cases were found. The sensitivity and specificity of NBS program for classical CAH forms were 100%; however, positive predictive value was only 4%. There were no significant differences between unscreened and screened male infant groups in terms of age at diagnosis, serum potassium, and serum sodium levels. Significant differences were found in weight at diagnosis between the groups (−1.67 ± 1.12 SDS versus 0.046 ± 1.01 SDS of unscreened and screened patients respectively, p = 0.001). Conclusions: The sensitivity and specificity of NBS for CAH program were 100%, but positive predictive value—only 4%. Weight loss was significantly lower and the weight SDS at diagnosis was significantly higher in the group of screened patients.

The presentation of congenital adrenal hyperplasia in an unscreened population

BACKGROUND

The aim of this study was to describe the incidence and spectrum of early clinical presentations of congenital adrenal hyperplasia (CAH) in an unscreened population.

METHODS

A national retrospective observational study was undertaken to identify all children diagnosed with CAH in the Republic of Ireland, between January 2005 and December 2019. Reporting clinicians completed anonymized clinical questionnaires.

RESULTS

There were 103 cases of CAH reported and 69 cases met the study inclusion criteria. The estimated annualized incidence of CAH in the Republic of Ireland was 1:14,754 or 0.07 cases per 1,000 live births. Forty-seven children presented clinically in the first six months of life, but only 17 of these had a confirmed diagnosis by day 10. Of these early presentations, there were 28 infants with salt-wasting, 15 females presented with virilized genitalia and four infants were detected due to a family history of CAH. Female infants presented at a median age of 0 days [IQR 0-1] and males at 14 days [IQR 9-21]. Seventy-eight percent of salt-wasting presentations occurred after day 10. Delays in clinical presentation, biochemical diagnosis and treatment initiation were identified.

CONCLUSIONS

The incidence of CAH is higher in Ireland than in other unscreened populations. In the absence of screening, clinicians should be aware of the possibility of CAH and appropriate investigations should be urgently requested. Life-threatening salt-wasting is the most frequent clinical presentation and many cases could be detected prior to decompensation if newborn screening were introduced.

Molecular Analysis of 21-Hydroxylase Deficiency Reveals Two Novel Severe Genotypes in Affected Newborns

BACKGROUND AND OBJECTIVE

Congenital adrenal hyperplasia involves a series of autosomal recessive disorders where adrenal steroidogenesis is affected. We present a detailed molecular investigation of 13 newborns affected from the severe form of congenital adrenal hyperplasia related to 21-hydroxylase deficiency.

METHODS

All patients were diagnosed with classical congenital adrenal hyperplasia in the neonatal period due to adrenal crisis and/or ambiguous genitalia presentation. None of the infants was identified through a congenital adrenal hyperplasia newborn screening program. A molecular analysis of the CYP21A2 gene and a familiar segregation analysis were performed.

RESULTS

Adrenal crisis was the most severe manifestation in the male salt-wasting newborns while all female patients presented with atypical genitalia. Newborns were correctly genotyped and no genotype-phenotype divergences were found. Two novel severe genotypes, not previously reported, were identified. The novel CYP21A2 frameshift mutations (c.793delG and c.297dupG) were added to the other 45 variants recently reported in the literature, leading to a total count of 279 pathogenic variants affecting the gene.

CONCLUSIONS

We have successfully genotyped 13 infants diagnosed with classical congenital adrenal hyperplasia after birth. Our molecular approach led to the identification of two novel frameshift CYP21A2 pathogenic variants related to the salt-wasting form of congenital adrenal hyperplasia.

The progression of salt-wasting and the body weight change during the first 2 weeks of life in classical 21-hydroxylase deficiency patients

BACKGROUND

One of the major purposes of newborn screening for 21-hydroxylase deficiency (21OHD) is preventing life-threatening adrenal crisis. However, the details of adrenal crisis in newborns are not precisely documented.

AIM

We aimed to clarify the clinical details of salt-wasting in newborn 21OHD patients.

METHODS

Based on the follow-up survey of the screening in Tokyo from 1989 to 2017, we retrospectively analysed the conditions of classical 21OHD neonates before the initiation of therapy.

RESULTS

One hundred classical 21OHD patients (55 male, 45 female) were analysed. The age at the first hospital visit was 0-20 days with sex difference (male: 9.0 ± 3.5 days; female: 6.2 ± 3.9 days). Thirty-seven (37.4%) patients exhibited severe salt-wasting (SSW), that is, Na < 130 mEq/L, K > 7 mEq/L or Na/K ratio < 20; except for one case, SSW developed in or after the second week of life. The serum concentrations of Na, K and Na/K were linearly correlated with age in days (R²  = .38, .25, and .34 respectively), suggesting that the risk of SSW increases linearly without a threshold. The age at which the regression lines reached Na < 130 mEq/L, K > 7 mEq/L and Na/K < 20 was approximately coincided, 11.1, 12.3 and 11.2 days, respectively. All SSW patients exhibited decreased body weight from birth in their second week of life.

CONCLUSION

Our data revealed that the risk of developing SSW increases during the second week of life without a threshold, and for preventing SSW, early intervention, ideally during first week of life, is desirable. An increased body weight in the second week of life indicates the absence of SSW.

The Cost-Effectiveness of Congenital Adrenal Hyperplasia Newborn Screening in Brazil: A Comparison Between Screened and Unscreened Cohorts

Background: Newborn screening for congenital adrenal hyperplasia (CAH-NBS) is not yet a worldwide consensus, in part due to inconclusive evidence regarding cost-effectiveness because the analysis requires an understanding of the short- and long-term costs of care associated with delayed diagnosis. Objective: The present study aimed to conduct a cost-effectiveness analysis (CEA) to compare the costs associated with CAH-NBS and clinical diagnosis. Methods: A decision model comparing the two strategies was tested by sensitivity analysis. The cost analysis perspective was the public health system. Unscreened patients' data were extracted from medical records of Hospital das Clinicas, Saõ Paulo, and screened data were extracted from the NBS Referral Center of São Paulo. The population comprised 195 classical patients with CAH, clinically diagnosed and confirmed by hormonal/CYP21A2 analysis, and 378,790 newborns screened during 2017. Adverse outcomes related to late diagnosis were measured in both cohorts, and the incremental cost-effectiveness ratio (ICER) was calculated. We hypothesized that CAH-NBS would be cost-effective. Results: Twenty-five screened infants were confirmed with CAH (incidence: 1:15,135). The mortality rate was estimated to be 11% in unscreened infants, and no deaths were reported in the screened cohort. Comparing the unscreened and screened cohorts, mean serum sodium levels were 121.2 mEq/L (118.3-124.1) and 131.8 mEq/L (129.3-134.5), mean ages at diagnosis were 38.8 and 17 days, and hospitalization occurred in 76% and 58% of the salt-wasting patients with the in the two cohorts, respectively. The NBS incremental cost was US$ 771,185.82 per death averted, which yielded an ICER of US$ 25,535.95 per discounted life-year saved. Conclusions: CAH-NBS is important in preventing CAH mortality/morbidity, can reduce costs associated with adverse outcomes, and appears cost-effective.

Challenges in Assessing the Cost-Effectiveness of Newborn Screening: The Example of Congenital Adrenal Hyperplasia

Generalizing about the cost-effectiveness of newborn screening (NBS) is difficult due to the heterogeneity of disorders included in NBS panels, along with data limitations. Furthermore, it is unclear to what extent evidence about cost-effectiveness should influence decisions to screen for specific disorders. Screening newborns for congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency can serve as a useful test case, since there is no global consensus on whether CAH should be part of NBS panels. Published and unpublished cost-effectiveness analyses of CAH screening have yielded mixed findings, largely due to differences in methods and data sources for estimating health outcomes and associated costs of early versus late diagnosis as well as between-country differences. Understanding these methodological challenges can help inform future analyses and could also help interested policymakers interpret the results of economic evaluations.

Newborn Screening for Congenital Adrenal Hyperplasia: Review of Factors Affecting Screening Accuracy

Newborn screening for 21-hydroxylase deficiency (21OHD), the most common form of congenital adrenal hyperplasia, has been performed routinely in the United States and other countries for over 20 years. Screening provides the opportunity for early detection and treatment of patients with 21OHD, preventing salt-wasting crisis during the first weeks of life. However, current first-tier screening methodologies lack specificity, leading to a large number of false positive cases, and adequate sensitivity to detect all cases of classic 21OHD that would benefit from treatment. This review summarizes the pathology of 21OHD and also the key stages of fetal hypothalamic-pituitary-adrenal axis development and adrenal steroidogenesis that contribute to limitations in screening accuracy. Factors leading to both false positive and false negative results are highlighted, along with specimen collection best practices used by laboratories in the United States and worldwide. This comprehensive review provides context and insight into the limitations of newborn screening for 21OHD for laboratorians, primary care physicians, and endocrinologists.

Evaluation of a Two-Tier Screening Pathway for Congenital Adrenal Hyperplasia in the New South Wales Newborn Screening Programme

In Australia, all newborns born in New South Wales (NSW) and the Australia Capital Territory (ACT) have been offered screening for rare congenital conditions through the NSW Newborn Screening Programme since 1964. Following the development of the Australian Newborn Bloodspot Screening National Policy Framework, screening for congenital adrenal hyperplasia (CAH) was included in May 2018. As part of the assessment for addition of CAH, the national working group recommended a two-tier screening protocol determining 17α-hydroxyprogesterone (17OHP) concentration by immunoassay followed by steroid profile. A total of 202,960 newborns were screened from the 1 May 2018 to the 30 April 2020. A threshold level of 17OHP from first tier immunoassay over 22 nmol/L and/or top 2% of the daily assay was further tested using liquid chromatography tandem mass spectrometry (LC-MS/MS) steroid profiling for 17OHP (MS17OHP), androstenedione (A4) and cortisol. Samples with a ratio of (MS17OHP + A4)/cortisol > 2 and MS17OHP > 200 nmol/L were considered as presumptive positive. These newborns were referred for clinical review with a request for diagnostic testing and a confirmatory repeat dried blood spot (DBS). There were 10 newborns diagnosed with CAH, (9 newborns with salt wasting CAH). So far, no known false negatives have been notified, and the protocol has a sensitivity of 100%, specificity of 99.9% and a positive predictive value of 71.4%. All confirmed cases commenced treatment by day 11, with none reported as having an adrenal crisis by the start of treatment.

Neonatal Screening for Congenital Adrenal Hyperplasia in Turkey: Outcomes of Extended Pilot Study in 241,083 Infants

OBJECTIVE

Turkish Directorate of Public Health introduced the first pilot screening program for congenital adrenal hyperplasia (CAH) in four Turkish cities in 2017, and in 2018 extended the program, with a slight change in screening strategy, to fourteen cities. To evaluate the performance of the extended study and update previously reported outcomes.

METHODS

Retrospective, descriptive study. Neonates of ≥32 gestational weeks and ≥1500 gr birth weight from fourteen cities, born between May-December 2018, were included. Screening protocol included one sample, two-tier testing as applied in the previous pilot study. In the first step, 17α-hydroxyprogesterone (17-OHP) was measured by fluoroimmunoassay in dried blood spots (DBS) obtained at 3-5 days of life. Cases with positive initial screening underwent second tier testing by steroid profiling in DBS using liquid chromatographyt-andem mass spectrometry to measure 17-OHP, 21-deoxycortisol (21-S), cortisol (F), 11-deoxycortisol and androstenedione. The babies with a steroid ratio (21-S+17-OHP)/F of ≥0.7 (increased from ≥0.5 in the earlier pilot study) were referred to pediatric endocrinology clinics for diagnostic assessment.

RESULTS

In the evaluated period, 241,083 newborns were screened. 12,321 (5.11%) required second-tier testing and 880 (0.36%) were referred for clinical assessment, twenty of whom were diagnosed with CAH (10 females, 10 males). Sixteen were diagnosed as classical 21-hydroxylase deficiency (21-OHD) CAH (12 with salt-wasting and four with simple virilising CAH), and four cases were identified with 11β-OHD CAH. No case of salt-wasting CAH was missed by neonatal screening (sensitivity was 100%). The incidence of classical 21-OHD and 11β-OHD in the screened population was 1:15,067 and 1:60,270, respectively.

CONCLUSION

Turkish neonatal CAH screening effectively led to earlier diagnosis of 21-OHD and 11β-OHD, using steroid profiling as a second-tier test. This will result in improved care of these patients in the future.

Newborn Screening Protocols and Positive Predictive Value for Congenital Adrenal Hyperplasia Vary across the United States

Newborn screening for congenital adrenal hyperplasia (CAH) caused by 21-hydroxylase deficiency is mandated throughout the US. Filter paper blood specimens are assayed for 17-hydroxyprogesterone (17OHP). Prematurity, low birth weight, or critical illness cause falsely elevated results. The purpose of this report is to highlight differences in protocols among US state laboratories. We circulated a survey to state laboratory directors requesting qualitative and quantitative information about individual screening programs. Qualitative and quantitative information provided by 17 state programs were available for analysis. Disease prevalence ranged from 1:9941 to 1:28,661 live births. Four state laboratories mandated a second screen regardless of the initial screening results; most others did so for infants in intensive care units. All but one program utilized birthweight cut-points, but cutoffs varied widely: 17OHP values of 25 to 75 ng/mL for birthweights >2250-2500 g. The positive predictive values for normal birthweight infants varied from 0.7% to 50%, with the highest predictive values based in two of the states with a mandatory second screen. Data were unavailable for negative predictive values. These data imply differences in sensitivity and specificity in CAH screening in the US. Standardization of newborn screening protocols could improve the positive predictive value.