The EQC test will present you several possible answers for the head, midpiece and tail. You can make only one choice. Although you may not be used to grade head shapes in your day-to-day activity, grading head shape is a convenient way of communicating sperm characteristics both to colleagues and medical staff. In our view, it is an important parameter to monitor in an External Quality Control scheme.
Several head shapes and sizes have been described by the WHO (1999, 2010).
|Normal||regular oval shape|
|Macrocephalic||the head is clearly above the normal|
|Microcephalic||the head is present but clearly smaller than the normal size|
|Elongated||the head has the form of a cigar|
|Pyriform||the head has the form of a pear|
|Amorphous||the head has slight to strong deviation from oval form|
|Double||two heads attached to one or two midpieces and tails|
|Pin||the head is absent, but the cells is alive and usually moves|
|Round||the head is perfectly spheric and no acrosome is present|
|Angulated||angulation of the midpiece in respect to the head axis|
|Asymetrical||asymetrical insertion of the midpiece into the head|
|Thick||thick or irregular midpiece|
|Thin||abnormally thin midpiece (absence of mitochondrial sheath)|
|Cytoplasmic droplet||cytoplasmic remnant larger than half of the head’s width|
The tail should be straight, uniform, thinner than the midpiece, uncoiled and about 45 µm long. Tail defects are presented below.
|Short or incompletely formed tail||Normal tail length is about 40-50 µm.|
|Multiple||A single head may ba associated with multiple tails|
|Irregular width||This parameter may be associated with osmotic effects or staining artifacts|
|Bent||Depending on the smear flagella may be curved, indicating movement of the sperm during the fixation procedure, or remain straight|
|Coiled||Various forms of coiling may occur, either during sperm maturation or after sperm collection (osmotic effects)|
Presence of vacuoles
The presence 1-2 vacuoles in the sperm head can be considered as normal. More than 2, should be considered as abnormal, according to the strict criteria.