Molecular Biology represents one of the most advanced and precise frontiers in laboratory diagnostics. Unlike traditional analyses that measure metabolic or cellular products, this discipline allows for the direct study of the “code of life,” namely the nucleic acids (DNA and RNA) present in human cells or pathogens. This capability has become an indispensable tool in many fields of modern medicine, particularly in infectious diseases, oncology, and genetics. In the realm of infectious diseases, molecular techniques (such as PCR – Polymerase Chain Reaction) enable the detection of viruses or bacteria with extremely high sensitivity and specificity, even when present in minimal quantities. Furthermore, they allow for the quantification of viral load (for example, HBV DNA in Hepatitis B or HCV RNA in Hepatitis C), a fundamental parameter for monitoring the effectiveness of antiviral therapies and determining their optimal duration. Another crucial application is the typing of pathogens such as Human Papillomavirus (HPV) to identify high oncogenic risk strains. These analyses provide detailed information essential for targeted and personalized clinical management.