A 20 yrs old young girl, presents with history of rapidly developing hirsutism and Amenorrhea with change in voice. To establish a diagnosis you would like to proceed with which of the following tests in blood:

Rapidly' progressing hirsutism points to developing androgen secreting tumors, which could be a Leydig seoli tumor of the ovary. For which estimation of androgens specifically serum testosterone should be an initial investigation along with a pelvic scan A 17 OH progesterone should be estimated as well to rule out a late onset Congenital adrenal hyperplasia.