MAIS is only diagnosed in normal phenotypic males, and is not typically investigated except in cases of male infertility [18]. MAIS has a mild presentation that often goes unnoticed and untreated [15]; even with semenological, clinical and laboratory data, it can be difficult to distinguish between men with and without MAIS, and thus a diagnosis of MAIS is not usually made without confirmation of an AR gene mutation [5].
The androgen sensitivity index (ASI), defined as the product of luteinizing hormone (LH) and testosterone (T), is frequently raised in individuals with all forms of AIS, including MAIS, although many individuals with MAIS have an ASI in the normal range [5]. Testosterone levels may be elevated despite normal levels of luteinizing hormone [15][20][24]. Conversion of testosterone (T) to dihydrotestosterone (DHT) may be impaired, although to a lesser extent than is seen in 5α-reductase deficiency [3]. A high ASI in a normal phenotypic male [45], especially when combined with azoospermia or oligospermia [5][7], decreased secondary terminal hair [26], and / or impaired conversion of T to DHT [3], can be indicative of MAIS, and may warrant genetic testing.