Changes in Test Volumes During Coronavirus Disease 2019 (COVID-19): A Laboratory Stewardship Opportunity.

CONTEXT.­: Coronavirus disease 2019 (COVID-19) changed the dynamics of health care delivery, shifting patient priorities and deferring care perceived as less urgent. Delayed or eliminated care may place patients at risk for adverse outcomes. OBJECTIVE.­: To identify opportunities for laboratory test stewardship to close potential gaps in care created by the COVID-19 pandemic. DESIGN.­: The study was a retrospective time series design examining laboratory services received before and during the COVID-19 pandemic at a large metropolitan health system serving women and children. RESULTS.­: Laboratory test volumes displayed 3 distinct patterns: (1) a decrease during state lockdown, followed by near-complete or complete recovery; (2) no change; and (3) a persistent decrease. Tests that diagnose or monitor chronic illness recovered only partially. For example, hemoglobin A1c initially declined 80% (from 2232 for April 2019 to 452 for April 2020), and there was a sustained 16% drop (28-day daily average 117 at August 30, 2019, to 98 at August 30, 2020) 4 months later. Blood lead dropped 39% (from 2158 for April 2019 to 1314 for April 2020) and remained 23% lower after 4 months. CONCLUSIONS.­: The pandemic has taken a toll on patients, practitioners, and health systems. Laboratory professionals have access to data that can provide insight into clinical practice and identify pandemic-related gaps in care. During the pandemic, the biggest patient threat is underuse, particularly among tests to manage chronic diseases and for traditionally underserved communities and people of color. A laboratory stewardship program, focused on peri-pandemic care, positions pathologists and other laboratory professionals as health care leaders with a commitment to appropriate, equitable, and efficient care.

Adrenoleukodystrophy: Guidance for Adrenal Surveillance in Males Identified by Newborn Screen.

Context: Adrenoleukodystrophy (ALD) is a peroxisomal disorder associated with neurologic decompensation and adrenal insufficiency. Newborn screening for ALD has recently been implemented in five states with plans to expand to all 50 states in the United States. Adrenal insufficiency ultimately develops in most males with ALD, but the earliest age of onset is not well established. Objective: These clinical recommendations are intended to address screening for adrenal insufficiency in boys identified to have ALD by newborn screen. Participants: Seven members of the Pediatric Endocrine Society Drug and Therapeutics/Rare Diseases Committee, with clinical experience treating children with ALD and adrenal insufficiency, and a pediatric endocrinologist and laboratory director were selected to be on the working committee. Consensus Process: The authors comprised the working group and performed systematic reviews of the published literature regarding adrenal insufficiency and ALD. The recommendations were reviewed and approved by the larger Pediatric Endocrine Society Drug and Therapeutics/Rare Diseases Committee and then by the Pediatric Endocrine Society Board of Directors. Conclusions: There is limited literature evidence regarding monitoring of evolving adrenal insufficiency in male infants and children with ALD. The recommendations suggest initiating assessment of adrenal function at diagnosis with ALD and regular monitoring to identify boys with adrenal insufficiency in a timely manner and prevent life-threatening adrenal crisis. These recommendations are intended to serve as an initial guide, with the understanding that additional experience will inform future guidelines.

A Longitudinal Study of Estrogen-Responsive Tissues and Hormone Concentrations in Infants Fed Soy Formula.

Purpose: Chemicals with hormonelike activity, such as estrogenic isoflavones, may perturb human development. Infants exclusively fed soy-based formula are highly exposed to isoflavones, but their physiologic responses remain uncharacterized. Estrogen-responsive postnatal development was compared in infants exclusively fed soy formula, cow-milk formula, and breast milk. Methods: We enrolled 410 infants born in Philadelphia-area hospitals between 2010 and 2014; 283 were exclusively fed soy formula (n = 102), cow-milk formula (n = 111), or breast milk (n = 70) throughout the study (birth to 28 or 36 weeks for boys and girls, respectively). We repeatedly measured maturation index (MI) in vaginal and urethral epithelial cells using standard cytological methods, uterine volume and breast-bud diameter using ultrasound, and serum estradiol and follicle-stimulating hormone levels. We estimated MI, organ-growth, and hormone trajectories by diet using mixed-effects regression splines. Results: Maternal demographics did not differ between cow-milk-fed and soy-fed infants but did differ between formula-fed and breastfed infants. Vaginal-cell MI trended higher (P = 0.01) and uterine volume decreased more slowly (P = 0.01) in soy-fed girls compared with cow-milk-fed girls; however, their trajectories of breast-bud diameter and hormone concentrations did not differ. We observed no significant differences between boys fed cow-milk vs soy formula; estradiol was not detectable. Breastfed infants differed from soy-formula-fed infants in vaginal-cell MI, uterine volume, and girls' estradiol and boys' breast-bud diameter trajectories. Conclusions: Relative to girls fed cow-milk formula, those fed soy formula demonstrated tissue- and organ-level developmental trajectories consistent with response to exogenous estrogen exposure. Studies are needed to further evaluate the effects of soy on child development.

Performance criteria for testosterone measurements based on biological variation in adult males: recommendations from the Partnership for the Accurate Testing of Hormones.

BACKGROUND: Testosterone measurements that are accurate, reliable, and comparable across methodologies are crucial to improving public health. Current US Food and Drug Administration-cleared testosterone assays have important limitations. We sought to develop assay performance requirements on the basis of biological variation that allow physiologic changes to be distinguished from assay analytical errors. METHODS: From literature review, the technical advisory subcommittee of the Partnership for the Accurate Testing of Hormones compiled a database of articles regarding analytical and biological variability of testosterone. These data, mostly from direct immunoassay-based methodologies, were used to specify analytical performance goals derived from within- and between-person variability of testosterone. RESULTS: The allowable limits of desirable imprecision and bias on the basis of currently available biological variation data were 5.3% and 6.4%, respectively. The total error goal was 16.7%. From recent College of American Pathologists proficiency survey data, most currently available testosterone assays missed these analytical performance goals by wide margins. Data from the recently established CDC Hormone Standardization program showed that although the overall mean bias of selected certified assays was within 6.4%, individual sample measurements could show large variability in terms of precision, bias, and total error. CONCLUSIONS: Because accurate measurement of testosterone across a wide range of concentrations [approximately 2-2000 ng/dL (0.069-69.4 nmol/L)] is important, we recommend using available data on biological variation to calculate performance criteria across the full range of expected values. Additional studies should be conducted to obtain biological variation data on testosterone from women and children, and revisions should be made to the analytical goals for these patient populations.

National status of testing for hypothyroidism during pregnancy and postpartum.

CONTEXT: Hypothyroidism, overt or subclinical, is associated with adverse outcomes for pregnant women and their offspring. Knowledge of current national thyroid testing rates and positivity during pregnancy is limited. OBJECTIVE: The aim of the study was to estimate thyroid testing rate and positivity during pregnancy and postpartum, including testing and positivity rates of thyroperoxidase antibody (TPO Ab) and free T(4) tests in pregnant women with elevated TSH levels (hypothyroid), and in pregnant women having TSH within range (euthyroid). DESIGN AND SETTING: Records from a large, national sample of pregnant women screened from June 2005 through May 2008 were examined. PARTICIPANTS: The study included 502,036 pregnant women, for whom gestational age information was available. MAIN MEASURES: Testing rates and the prevalence of hypothyroidism during pregnancy and postpartum were measured using assay-specific, trimester-specific reference intervals. Screening and positivity rates of TPO Ab and free T(4) tests were also measured. RESULTS: Of women ages 18 to 40 yr, 23% (117,892 of 502,036) were tested for gestational hypothyroidism (defined as both subclinical and overt hypothyroidism). Of these, 15.5% (18,291 of 117,892) tested positive for gestational hypothyroidism. Twenty-four percent (22,650 of 93,312) of women with TSH within range and 33% (6,072 of 18,291) of women with elevated TSH were also tested for gestational hypothyroxinemia. Gestational hypothyroxinemia was seen in 0.2% (47 of 22,650) of the tested women with TSH within range and was seen in 2.4% (144 of 6,072) of the tested women having elevated TSH; 0.3% (276 of 93,312) of women with TSH within range received a TPO Ab test, and of these, 15% (41 of 276) tested positive; 0.66% (120 of 18,291) of women with elevated TSH received a TPO Ab test, and of these, 65% (78 of 120) tested positive. Only 20.7% (1873 of 9063) of hypothyroid women received thyroid screening within 6 months postpartum; of these, 11.5% (215 of 1873) were diagnosed with postpartum hypothyroidism. CONCLUSION: Gestational hypothyroidism is more common than generally acknowledged. Testing is not common, and test selection is variable. There is a low rate of postpartum follow-up.

Gaps in diabetes screening during pregnancy and postpartum.

OBJECTIVE: To estimate the screening rate and prevalence of gestational diabetes mellitus (GDM) and the screening rate and prevalence of postpartum diabetes, in a large, national sample of pregnant women. We also estimated the potential effects of the new International Association of Diabetes and Pregnancy Study Groups recommendations, which replace the 100-g oral glucose tolerance test (OGTT) with the 75-g OGTT, on GDM prevalence and gestational plasma glucose testing practices. METHODS: We identified pregnant women who used the laboratory services of Quest Diagnostics and who were screened for GDM and were tested postpartum. Gestational diabetes mellitus prevalence was calculated according to the current American Diabetes Association/ Carpenter-Coustan criteria, and the new International Association of Diabetes and Pregnancy Study Groups criteria. RESULTS: Sixty-eight percent (632,820/924,873) of pregnant women aged 25 to 40 (ie, those not in a low-risk age group) who utilized the services of Quest Diagnostics during this study were screened for GDM. Of the entire adult pregnant population (ages 18-40) who received GDM screening, 5% (40,955/842,993) had positive test results under the current criteria. Nineteen percent (4,486/23,299) of those with GDM received postpartum diabetes testing within a 6-month period. Ninety percent (148,749/166,085) of all confirmatory GDM tests performed on pregnant women at Quest Diagnostics were the 100-g OGTT. The number of women with GDM after receiving the 75-g OGTT would have doubled under the International Association of Diabetes and Pregnancy Study Groups criteria. CONCLUSION: Many women may not be receiving GDM screening during pregnancy. Postpartum diabetes screening rates after pregnancy remain low. Adoption of the new International Association of Diabetes and Pregnancy Study Groups criteria would require a significant change in current clinical practice. LEVEL OF EVIDENCE: III.

Validation and clinical application of a locus-specific polymerase chain reaction- and minisequencing-based assay for congenital adrenal hyperplasia (21-hydroxylase deficiency).

Congenital adrenal hyperplasia is an autosomal recessive disorder caused by defective adrenal steroid biosynthesis, resulting in reduced glucocorticoid and increased androgen production. The majority of cases are due to inactivation of the 21-hydroxylase gene (CYP21A2), most commonly caused by genomic rearrangements with the adjacent, highly homologous pseudogene CYP21A. The most common deletions and gene conversion events have been defined and are typically detected by Southern hybridization detection of CYP21 rearrangements and/or polymerase chain reaction (PCR). However, Southern hybridization is laborious, and allele-specific PCR results may be difficult to interpret. We have therefore developed a locus-specific, PCR-based, minisequencing method for detecting the 12 most common CYP21A2 mutations. We validated the assay using a panel of 20 previously genotyped samples obtained from individuals who collectively have a broad spectrum of mutations causing 21-hydroxylase deficiency. We also used 19 control samples having no CYP21 mutations. All validation samples were correctly typed, and we identified haplotypes that may be useful for clinical diagnosis. Results from 102 clinical samples demonstrate that this assay is a rapid, reliable, and robust method for locus-specific identification of mutations and is suitable for routine clinical use and prenatal diagnosis.

Rational use of the laboratory for childhood and adult growth hormone deficiency.

No laboratory test has sufficient diagnostic sensitivity and specificity to serve as a gold standard for the diagnosis for GHD: therefore, test results must be interpreted after assessment of risk for GHD is determined on clinical grounds. Growth data are particularly crucial for diagnosis of childhood GHD;history of known pituitary damage and presence or absence of other pituitary hormone deficiencies are the critical elements for the diagnosis of adult GHD. New reference preparations are available for GH and IGF-I and should greatly aid interassay comparisons when the preparations are universally adopted.GH stimulation testing remains a key part of the diagnosis of adult GHD, but is currently being de-emphasized for the diagnosis of pediatric GHD. Better interassay comparative data and organized clinical collaboration between clinicians and test manufacturers/laboratories to set rational clinical diagnostic cutoffs would improve greatly the clinical usefulness of GH stimulation testing. The availability of statistically sound age- and sex-related normative data for IGF-I and IGFBP3 make these key tests for the diagnosis of childhood GHD. Although IGF-I may not be a perfect test for the diagnosis of adult GHD, it may be sufficiently informative in many cases to warrant using it ona routine basis. IGF-I also has a role in monitoring the safety of adult patients who are on GH treatment; studies are underway to determine if IGF-I may be useful in the future for optimization of GH dosaging.

Autosomal dominant pseudohypoparathyroidism type Ib is associated with a heterozygous microdeletion that likely disrupts a putative imprinting control element of GNAS.

Patients with pseudohypoparathyroidism type Ib (PHP-Ib) have hypocalcemia and hyperphosphatemia due to renal parathyroid hormone (PTH) resistance, but lack physical features of Albright hereditary osteodystrophy. PHP-Ib is thus distinct from PHP-Ia, which is caused by mutations in the GNAS exons encoding the G protein alpha subunit. However, an imprinted autosomal dominant form of PHP-Ib (AD-PHP-Ib) has been mapped to a region of chromosome 20q13.3 containing GNAS. Furthermore, loss of methylation at a differentially methylated region (DMR) of this locus, exon A/B, has been observed thus far in all investigated sporadic PHP-Ib cases and the affected members of multiple AD-PHP-Ib kindreds. We now report that affected members and obligate gene carriers of 12 unrelated AD-PHP-Ib kindreds and four apparently sporadic PHP-Ib patients, but not healthy controls, have a heterozygous approximately 3-kb microdeletion located approximately 220 kb centromeric of GNAS exon A/B. The deleted region, which is flanked by two direct repeats, includes three exons of STX16, the gene encoding syntaxin-16, for which no evidence of imprinting could be found. Affected individuals carrying the microdeletion show loss of exon A/B methylation but no epigenetic abnormalities at other GNAS DMRs. We therefore postulate that this microdeletion disrupts a putative cis-acting element required for methylation at exon A/B, and that this genetic defect underlies the renal PTH resistance in AD-PHP-Ib.