CAH StripAssay® Diagnosing Congenital Adrenal Hyperplasia

Congenital Adrenal Hyperplasia (CAH) remains one of the most complex metabolic disorders inherited at birth, affecting the synthesis of vital adrenal steroid hormones like cortisol and aldosterone. The symptoms can range from virilization in female newborns to life-threatening salt-wasting conditions, which makes early and accurate diagnosis vital. Traditionally, CAH diagnosis involved neonatal screening based on the assessment of 17-hydroxyprogesterone (17-OHP) levels, a method riddled with high false positives.

A Multi-Step Diagnostic Procedure

The CAH StripAssay® follows a detailed, multi-step diagnostic procedure beginning with DNA isolation. After this, polymerase chain reaction (PCR) amplification takes place using biotinylated primers. The next step is a hybridization process, which occurs on a test strip containing allele-specific oligonucleotide probes immobilized as parallel lines. The assay ultimately identifies bound biotinylated sequences using streptavidin-alkaline phosphatase and color substrates.

Cost and Time Efficiency

One of the primary reasons to use CAH StripAssay®  is its cost and time efficiency compared to whole gene sequencing. While sequencing the entire gene provides an exhaustive list of possible mutations, it is often overkill for a disease like CAH, where the most common mutations are already well-documented. In that sense, the CAH StripAssay® delivers targeted results without incurring the unnecessary cost and time of a more extensive test.

A Clinical Imperative

Given the importance of early and accurate diagnosis—particularly for the severe salt-wasting form of the disease—current newborn screening programs are crucial as they may identify potential cases. However, the possibility of false positives typically requires a secondary, confirmatory test. The CAH StripAssay® serves as a useful second-tier test that can help reduce the number of false positives, aiding clinicians in making more informed decisions.