Immunology

A clear guide to Anti-thyroid peroxidase (Anti-TPO) and Anti-thyroglobulin (TG Ab) tests, including purpose, reference ranges, and clinical interpretation.

CA19-9 is a key tumor marker for pancreatic and biliary cancers. Learn its normal range, causes of elevation, limitations, and how to interpret results accurately.

Understanding the HE4 Blood Test: A Laboratory Medicine Specialist’s Guide to Interpretation Introduction Written by a Laboratory Medicine Specialist (MD.PhD.) When a pelvic mass is found on imaging, one of the most clinically urgent questions becomes: is it benign or malignant? The HE4 blood test — short for Human Epididymis Protein 4 — has emerged…

Understanding CA72-4: A Laboratory Specialist’s Guide to This Gastric Cancer Tumor Marker What this test measures, when it matters, and how to interpret it correctly — with clinical context you won’t find on the lab report. Laboratory Medicine Specialist, MD.PhD. CA72-4 (Cancer Antigen 72-4) is a high-molecular-weight mucin-type glycoprotein tumor marker most closely associated with…

CYFRA 21-1 Tumor Marker: A Specialist’s Guide to Lung Cancer Diagnosis and Monitoring By a Laboratory Medicine Specialist, MD.phD. CYFRA 21-1 (Cytokeratin 19 Fragment) is a serum tumor marker with particular clinical value in non-small cell lung cancer (NSCLC), especially squamous cell carcinoma. This article — written by a board-certified Laboratory Medicine Specialist — explains…

Understanding ECP (Eosinophil Cationic Protein): A Specialist’s Guide to Allergic Inflammation Testing What your ECP result reveals about eosinophil activation, allergic disease activity, and treatment response — explained by a Laboratory Medicine Specialist. As a Laboratory Medicine Specialist, I frequently encounter ECP requests from allergists and pulmonologists looking for answers that a simple eosinophil count…

CH50 Total Complement Activity Test: A Laboratory Medicine Specialist’s Complete Guide to Purpose, Method & Interpretation Written by a Laboratory Medicine Specialist (MD.phD.) Introduction As a Laboratory Medicine Specialist, I frequently receive requests to explain why CH50 is ordered alongside C3 and C4 — and why a single complement result is never enough to tell…

Anti-CCP Antibody Test Explained: A Laboratory Medicine Specialist’s Guide to Rheumatoid Arthritis Diagnosis Introduction This article is written by a Laboratory Medicine Specialist (MD.phD.) with clinical expertise in autoimmune serology, immunoassay diagnostics, and rheumatological laboratory evaluation. The Anti-CCP antibody test (anti-cyclic citrullinated peptide antibody) is one of the most diagnostically powerful tools available for the…

The leptin test helps evaluate metabolic, reproductive, and nutritional health. Learn its purpose, RIA method, reference ranges, and interpretation.