A presence/absence test for Staphylococcus aureus (S. aureus) involves placing a first generation test sample in a solution that will clot in the presence of S. aureus. The solution contains components that will selectively grow S. aureus and also contains clotting factors that will react with S. aureus, if S. aureus is present in the sample, to clot the solution. Examples of specimen samples that can be tested include nasal swabs and lesion swabs, among others. The test can also be modified to detect the presence or absence of methicillin resistant S. Aureus (MRSA).