Ovulation can be diagnosed by all except
Tests for ovulation: Basal body temperature, Endometrial biopsy, Fern test, and ultrasound.
But plasma concentration of progesterone rises only after ovulation and reaches its the peak of 15ng/ml by mid-luteal phase.
Measuring day 14 serum progesterone
Rise in basal body temperature in the second half of cycle
Study of cervical mucus
Endometrial histology