To determine if a man has teratozoospermia or not, the number of sperm with an abnormal morphology must be determined using a semen analysis or sperm test. The results of this test can be calculated using two different criteria:
- Males with a percentage of normal sperm below 4% are considered teratozoospermic.
- Males with a percentage of normal sperm below 15% are considered teratozoospermic.
As one can see, the Kruger's criteria are stricter than the ones published by the WHO. Thus, a man can be diagnosed with teratozoospermia if the Kruger's criteria is followed, whilst his sample would be considered normal according to the WHO's guidelines.