What is the Kruger criteria?
The Kruger criteria are stricter criteria than those of the World Health Organization (WHO) used to evaluate sperm morphology.
A seminal sample is considered normal when it presents 14-15% of spermatozoa with normal shapes. Instead, the WHO establishes a lower limit of normality, since only 4% is needed.
Therefore, a semen sample with more than 85% amorphous sperm would be diagnosed with teratozoospermia taking into account the Kruger criteria.