Molecular biology is the section of biology that studies the molecular basis of different biological activities. Molecular biologists in a pathology lab use molecular cloning, blotting, chain reaction, gel electrophoresis, and polymerase as techniques to quantify, collect, isolate, and facilitate molecules.

Molecular biology tests that take place in a diagnostic centre are:

• PCR technique in testing HBV DNA in the liver cells or blood.
• Real-time PCR technique for testing HIV.