Computer Assisted Semen Analysis

The CASA is the study of version 1.0 (Image House A/S, Copenhagen, Denmark). It calculated the CASA parameters of sperm motility according to WHO guidelines (1992). Change to : CASA is an advanced system which enables in automatic accurate assessment of a sperm for its motility, morphology, concentration, DNA fragmentation and vitality.

Computer Assisted Semen Analysis (CASA)

A semen analysis is a test performed to screen for male fertility problems. Computer-aided sperm analysis (CASA) technology is a technology developed in the late 1980s for analysing sperm movement characteristics or kinematics and has been highly successful in enabling this field of research. In an attempt to make the assessments of semen quality more objective and detailed, tools for computer-assisted semen analysis have been developed.

How is it done?

In order to perform a semen analysis, a man must collect a semen specimen into a sterile cup. This is usually done by masturbation, although in some cases it can be obtained during intercourse by the use of a special condom. After obtaining the sperm specimen, it is placed on the microscope stage of the CASA equipment. A high-resolution video camera is mounted to this

microscope, which sends data to the computer for analysis. A computerised sperm analysis with the required software will provide the fertility specialist with many additional parameters to investigate for the diagnosis of infertility. The findings obtained through the CASA method are accurate and reproducible.

Advantages of CASA

In contrast to manual counting, CASA uses hardware and software to visualise and evaluate consecutive images of viable sperms so as to obtain precise and valid information on the kinematics of individual sperms. Some of the data obtained by CASA include

  • Overall motility - percentage of sperm showing any movement
  • Rapid motility - percentage of sperm travelling at a speed of 25 μm/sec or faster
  • Linearity - percentage of sperm moving in a straight line path
  • Progressive motility - percentage of sperm moving rapidly and in a straight path
  • Mean velocities - average speed for all sperm in the field of view
  • Amplitude of lateral head displacement - the average distance that the sperm head “wiggles” back and forth while moving

CASA provides fast, accurate and objectively repeatable results. A precise morphological and morphometric analysis of each spermatozoa is provided in real time. This equipment can also perform certain specialised tests for parameters such as sperm vitality & sperm DNA fragmentation index, all of which help to identify the reasons for fertility.

Although CASA has several advantages as compared to manual analysis, human clinical semen analysis has many inherent difficulties caused by sperm clumping and heavy background debris. Also, this complex system is susceptible to false negative or positive results due to inappropriate use. Hence, a thorough validation procedure as well as user training is absolutely necessary in order to profit from these powerful machines. CASA systems provide information important for quality assurance of semen, and for the understanding of the diversity of sperm responses to changes in the microenvironment research, and thus helps in understanding deeper problems related to male infertility.