Which type of plasma is employed in the tube coagulase test?

The tube coagulase test is specifically designed to detect the presence of coagulase enzyme produced by certain strains of Staphylococcus bacteria, particularly Staphylococcus aureus. Rabbit plasma is used in this test due to its properties that allow for effective coagulation reactions.

The coagulase enzyme converts fibrinogen, a soluble plasma protein, into fibrin, which forms a solid clot. Rabbit plasma contains an adequate level of fibrinogen and is sensitive to the action of the coagulase enzyme, making it the most suitable choice for this diagnostic procedure.

Other types of plasma, such as human, sheep, or horse, may not provide the same reliability or consistency in coagulation, as their composition and levels of fibrinogen can vary. This can lead to inconsistent test results that may not accurately indicate the presence of coagulase-positive bacteria. Therefore, the use of rabbit plasma ensures the test's specificity and reliability in identifying Staphylococcus aureus.