Diagnostic tests are tools or techniques used by healthcare professionals to identify and diagnose diseases or medical conditions in patients. These tests can include laboratory tests, imaging scans, physical exams, and other procedures to help healthcare providers make informed decisions about a patient's health. Diagnostic tests play a crucial role in identifying and treating diseases early, monitoring the progression of diseases, and evaluating the effectiveness of treatments. Ultimately, diagnostic tests help healthcare providers to provide accurate and timely care to their patients.