The Stain-Gram test is often ordered in order to check to see if you have bacterial infection and whether the infection in question is being caused by gram positive or gram negative bacterium. Usually, most bacterial infections are often identified by the resulting symptoms, however, a stain gram test can help your doctor to clearly identify the type of bacteria and thereby can enable him to treat your infection with the right antibiotics. Your doctor may require you to submit samples for the test, the results of which should become available within 24 hrs. You may be required to submit the one or more of the following samples, for the test. Tissue, Blood, Urine, Stool, Sputum.