Evaluation
The evaluation depends on the formation of lumps, the so-called agglutination. If the formation of lumps occurs after the plasma and bacterium have been mixed on the slide or the test tube, the test is positive and it is a coagulase-positive Staphylococcus bacterium. If no lumps are formed but a milky cloud without agglutinates, the test is negative and it is a coagulase-negative Staphylococcus bacterium. Often, some of the colony material is additionally mixed with a saline solution for control purposes.
Duration
The coagulase test is very time consuming and takes about 24 hours. There are different methods to increase the specificity and sensitivity of the test. For example, another pathogenicity factor, protein A, can be detected simultaneously. This is done by some providers as a combined test. The better the result, the longer the duration.
Costs
The costs for a coagulase test are not very high. A quick test costs about 20€. On top of that there might be fees for the doctor’s visit, taking the sample, sending it to the laboratory and working hours.
In total it should cost around 50€. However, this depends on whether you have private or statutory health insurance. In most cases the costs are covered by the health insurance.
What are the alternatives?
So far there is no alternative test for the detection of the clumping factor. Often, however, the clinical picture and symptoms are sufficient for a reliable diagnosis. For the detection of MRSA, there are various rapid tests that are used upon admission to hospital.There is also a test to differentiate between staphylococci and streptococci.
