what are the three resons the slide coagulase test must be c

what are the three resons the slide coagulase test must be confirmed by tube coagulase

Solution

In slide test, the positive results are due to the agglutination of coagulase bound cells. The reaction between the coagulase and fibrinogen causes precipitation of fibrinogen. To observe this clumping of cells, the slide is to be observed under the light box.

In case of tube test, the agglutination is due to the presence of free coagulase (not bound to cells). We can directly observe the result in a tube test, so it is more suitable to detect free coagulase.

Tube coagulase test is used to confirm the coagulase test results because,

1). The tube test allows direct observation of the result

2). Some of the bacterial strains produce fibrinolysis that dissolve formed clot, which gives false negative result with slide coagulase test