Hepatitis A blood tests check for immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies. An IgG-positive and IgM-negative result may suggest immunity to hepatitis A. A doctor may request a ...

There are many ways of classifying bacteria. One method is based on the cell membrane. In 1884, a bacteriologist named Christian Gram created a test that could determine if a bacterium had a thick, ...

Gram-positive bacteria show blue or purple after Gram-staining in a laboratory test. They have thick cell walls. Gram-negative bacteria show pink or red on staining and have thin walls. They release ...