After basal levels have been measured, confirmation is done by administering ACTH, and comparing 17-OHP pre and post test. 17-OHP levels over 10 ng/mL at the 60th minute post stimulation is considered diagnostic for LOCAH. Androgen backdoor pathway
In 21-hydroxylase deficiency, especially in mild cases (LOCAH), the androgen "backdoor" pathway may be the reason of androgen excess. This backdoor pathway is not always considered in the clinical evaluation of patients with hyperandrogenism conditions such as LOCAH and may be a source of diagnostic pitfalls and confusion. One case study demonstrated the importance of considering serum 5α-dihydrotestosterone (DHT) levels and the androgen backdoor pathway in a LOCAH diagnosis that would have not been apparent from testosterone levels alone. 11β-Hydroxylase deficiency
The activity of 11β-hydroxylase can be determined by observing the basal  11-deoxycortisol level. A level over 10 ng/mL, indicates followup with ACTH stimulation test. The 60th minute post-stimulation 11-deoxycortisol levels higher than 18 ng/mL are diagnostic of LOCAH. 3β-Hydroxysteroid dehydrogenase deficiency
The activity of 3β-hydroxysteroid dehydrogenase can be determined by observing the basal 17α-hydroxypregnenolone level. A level above 30 ng/mL and 17α-hydroxypregnenolone/cortisol ratio above 10 SD are diagnostic of LOCAH. Management
Management and treatment of LOCAH is case specific and the application of glucocorticoid treatment is not standard as it is in classic CAH. LOCAH is not a life-threatening medical condition and the risks of treatment given prenatally or to asymptomatic children outweigh potential benefits.
The most elaborate regimen entails a random blood glucose test during a booking visit, a screening glucose challenge test around 24–28 weeks gestation, followed by an OGTT if the tests are outside normal limits. If there is a high suspicion, a woman may be tested earlier.In the United States, most obstetricians prefer universal screening with a screening glucose challenge test. In the United Kingdom, obstetric units often rely on risk factors and a random blood glucose test. The American Diabetes Association and the Society of Obstetricians and Gynaecologists of Canada recommend routine screening unless the woman is low risk (this means the woman must be younger than 25 years and have a body mass index less than 27, with no personal, ethnic or family risk factors) The Canadian Diabetes Association and the American College of Obstetricians and Gynecologists recommend universal screening. The U.S. Preventive Services Task Force found there is insufficient evidence to recommend for or against routine screening, and a 2017 a Cochrane review found that there is not evidence to determine which screening method is best for women and their babies.Some pregnant women and careproviders choose to forgo routine screening due to the absence of risk factors, however this is not advised due to the large proportion of women who develop gestational diabetes despite having no risk factors present and the dangers to the mother and baby if gestational diabetes remains untreated.