Diagnostic Tests Physicians Order: Comprehensive Guide by Category

Physicians order tests based on symptoms, history, exam findings, and suspected conditions. Common categories:

1. Blood Tests

• CBC: RBCs, WBCs, platelets, Hb, Hct → anemia, infection, clotting disorders
• Metabolic panels: Electrolytes, kidney/liver function, glucose
• Coagulation studies: PT/INR, PTT
• Inflammatory markers: CRP, ESR
• Hormone levels: Thyroid, reproductive, cortisol
• Cardiac enzymes: Troponin, CK-MB

2. Urine Tests

• Urinalysis: Physical/chemical/microscopic → UTI, kidney disease, diabetes
• Urine culture: Identifies specific pathogens

3. Imaging

• X-ray: Bones, chest, abdomen
• CT: Detailed cross-sections → trauma, tumors, infections
• MRI: Soft tissue detail → brain, joints, spine
• Ultrasound: Real-time, no radiation → abdomen, pelvis, vascular, fetal

4. Cardiac

• ECG: Electrical activity → arrhythmias, ischemia
• Stress test: Exercise/pharmacologic + imaging
• Echocardiogram: Structure/function

5. Endoscopic

• Colonoscopy: Colon/rectum → polyps, cancer screening
• EGD: Esophagus, stomach, duodenum

6. Biopsy

Tissue sampling for microscopy → cancer, infections, autoimmune

7. Pulmonary Function Tests

Lung function → asthma, COPD, restrictive disease

8. Neurological

Reflexes, cognition, nerve conduction → stroke, MS, Parkinson's

Test selection is individualized—clinical reasoning guides the diagnostic pathway.