CASA Variable

Description

Motile

Percentage of total sperm moving at a track velocity ≥30 µm/sec and progressive velocity ≥15 µm/sec

Progressive

Percentage of total sperm moving at a track velocity ≥50 µm/sec and straightness ≥70%

Rapid

Percentage of Progressive % with path velocity >50 µm/sec

Medium

Percentage of Progressive % with path velocity <50 µm/sec but >30 µm/sec

Slow

Percentage of Progressive % with path velocity <30 µm/sec and progressive velocity <15 µm/sec

Static

Sperm with no movement at all

Path Velocity (VAP)

Average velocity of the smoothed cell path (µm/sec)

Progressive Velocity (VSL)

Average velocity measured in a straight line from the beginning to the end of the track

Track Speed (VCL)

Average velocity measured over the point-to-point track

Lateral Amplitude (ALH)

Mean width of the head oscillation as the sperm swims

Beat Frequency (BCF)

Frequency of sperm head crossing the sperm average path in either direction

Straightness (STR)

Measures departure of average sperm path from straight line (ratio of VSL/VAP)

Linearity (LIN)

Measures departure of actual sperm path from straight line (ratio of VSL/VCL)

Elongation (ELONG)

Ratio of head width to head length

Sperm Head Size (AREA)

Average size in square micrometers of all sperm heads