• Diagnose congenital adrenal hyperplasia (mild as well as severe forms) in the newborn

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder characterized by deficiency of any one of 4 enzymes required for cortisol synthesis in the adrenal gland. Clinical symptoms vary according to the particular enzyme deficiency and include developmental abnormalities of the external genitalia and salt wasting (sodium and potassium imbalance). Differential diagnosis and treatment in the neonatal period is necessary to minimize morbidity and mortality.

CAH diagnosis is based on clinical findings, biochemical and hormonal test results, karyotyping, and sometimes mutation analysis.¹ Although single hormone levels may be useful, ACTH stimulation tests are frequently required. In some cases, hormonal precursor-product ratios are needed to establish the definitive diagnosis. The precursor (ie, substrate of the deficient enzyme) is often elevated, and the product is decreased, leading to an elevated ratio. The differential diagnosis is made based on the pattern of precursor-product ratios.

Current testing necessitates blood sample collections that are invasive and difficult to obtain in newborn infants. This profile, however, provides random urine levels for 34 different steroid metabolites as well as 4 precursor-product ratios for 21-hydroxylase (21-OH) deficiency diagnosis, 3 for 17-hydroxylase (17-OH) deficiency, 2 for 11ß-hydroxylase (11ß-OH) deficiency, and 2 for 3ß-hydroxysteroid dehydrogenase (3ß-HSD) deficiency. 

• Infants with genital ambiguity

• Infants with hyponatremia and hyperkalemia

• Infants with a family history of CAH

7.0 mL frozen random urine (2.1 mL minimum)

Use a premature infant diaper to collect a random urine sample: (1) remove the wet diaper from the baby; (2) remove and discard the top liner of the diaper; (3) insert the wetted diaper pad into a 20 cc syringe barrel; (4) replace the syringe plunger and press down to squeeze out urine; (5) mix well and freeze without preservatives.

• Gas Chromatography/Mass Spectrometry (GC/MS)

• Solid-phase extraction of urinary steroids

• Enzyme hydrolysis 

• Chromatography 

• GC/MS analysis

• Report includes µg/g creatinine for each steroid, 11 ratios, and interpretation

• Analytical sensitivity: see Table 1

• CPT code*:  82542

Steroid pediatric reference ranges: see Table 1
Precursor-product ratio pediatric reference ranges: see Table 2

Over 90% of CAH cases are attributed to 21-hydroxylase deficiency, which is associated with increased levels of the following precursor-product ratios: (1) 15ß,17α-dihydroxypregnanolone x 100:denominator; (2) 17α-hydroxypregnanolone x 100:denominator; (3) pregnanetriol x 100:denominator; and (4) pregnanetriolone x 100:denominator.² The denominator used is the summation of cortisol product metabolites including tetrahydrocortisone (THE), α-cortolone, and ß-cortolone.² A fifth ratio, pregnenetriol x 100:pregnanetriolone, is used to differentiate 21-OH deficiency from the rare 3ß-HSD deficiency. These ratios, as well as those used for the other forms of CAH, can be viewed in  Table 2.

Results from each patient are reviewed and interpreted by a Scientific or Medical Director at Quest Diagnostics Nichols Institute. An Academic Associate is consulted on difficult cases. 

Figures 1-3 illustrate the observed differentiation between 21-OH deficient individuals and normal individuals. Differentiation between 21-OH deficiency and 3ßHSD deficiency is illustrated in Figure 4.