What is the difference between WHO and Kruger morphology?
The WHO laboratory manual for the examination of human semen and sperm-cervical mucus interaction 1999, 4th edition recommends that laboratories assess morphology by preparing a stained slide and, visualizing the slide under an oil emersion microscope, classify 200 sperm cells based on evidence or absence of morphological defects. WHO has defined the standard for normal cell morphology and deviations from this norm are categorized by the location of the morphological defect (head, mid-piece, tail). Two “criteria” for assessing normal morphology are accepted as an international standard: WHO Non-strict criteria (based upon WHO 3rd edition criteria) and Kruger/strict criteria (based upon WHO 4th edition criteria). The difference between these two criteria is mostly based upon how “borderline” normal sperm cells are treated (Kruger designating them as ABNORMAL whereas according to WHO 3rd edition they are considered to be normal). Therefore, when assessing morphology based upon Kruger (st
