Diagnostic Microbiology is the study of microorganisms responsible for human diseases to identify and diagnose infections. It focuses on detecting bacteria, viruses, fungi, and parasites from clinical samples like blood, urine, or sputum. Techniques used include microscopy, culture methods, biochemical tests, serology, and molecular diagnostics such as PCR. Accurate diagnosis helps guide appropriate treatment and prevent the spread of infection. Antibiotic sensitivity testing is also a key part of this field. Diagnostic microbiology plays a critical role in hospital infection control and public health surveillance. Rapid and precise identification of pathogens improves patient outcomes. It is an essential discipline in medical laboratories and healthcare systems.