[MD.PhD.] Understanding the CA19-9 Blood Test
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.
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[MD.PhD.] Understanding the HE4 Blood Test
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…
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[MD.PhD.] Understanding CA72-4
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…
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[MD.phD.] CYFRA 21-1 Tumor Marker
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…
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[MD.phD.] Procalcitonin (PCT) Test
Procalcitonin (PCT) Test: A Specialist’s Complete Guide to Sepsis Diagnosis and Antibiotic Stewardship By Laboratory Medicine Specialist, MD.phD. Quick summary: Procalcitonin (PCT) is a blood biomarker that rises sharply and specifically in bacterial infections and sepsis, while remaining low in viral illnesses — making it one of the most clinically valuable tools for guiding antibiotic decisions…
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[MD.phD.] CRP (C-Reactive Protein) Test
CRP (C-Reactive Protein) Test: A Specialist’s Guide to Understanding Inflammation Markers By Laboratory Medicine Specialist, MD.phD. Quick summary: The CRP (C-reactive protein) test is a blood test that measures a key marker of inflammation produced by the liver. It rises sharply within hours of infection, injury, or inflammatory disease — making it one of the most…
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[MD.phD.] CRP vs. hs-CRP
CRP vs. hs-CRP: A Laboratory Medicine Specialist’s Guide to Understanding the Difference Written by a Laboratory Medicine Specialist, MD.phD. Introduction As a Laboratory Medicine Specialist, one of the most common questions I receive from clinicians and patients alike is: “What is the difference between CRP and hs-CRP — aren’t they the same thing?” They measure…
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[MD.phD.] “Left Shift” in Blood Tests
Understanding “Left Shift” in Blood Tests: A Laboratory Medicine Specialist’s Guide Written by a Laboratory Medicine Specialist, MD.phD. Introduction If you have ever received a CBC (complete blood count) report and noticed the phrase “left shift,” you may have wondered what it means — and whether it signals something serious. As a Laboratory Medicine Specialist,…
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WBCs Can Drop During Infection?
Why White Blood Cells Can Drop During Infection: A Specialist’s Guide to Leukocyte Margination and WBC Distribution Written by a Laboratory Medicine Specialist (MD) Introduction As a Laboratory Medicine Specialist, few findings generate more urgent phone calls from clinical colleagues than an unexpectedly low white blood cell count in a patient who is clearly unwell….
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[MD.phD.] Leukopenia vs Neutropenia
Leukopenia vs. Neutropenia: A Laboratory Medicine Specialist’s Guide to the Key Differences Leukopenia refers to a total white blood cell count below 4,000/µL, while neutropenia specifically means a low absolute neutrophil count — the single most important predictor of infection risk. Though the two conditions frequently overlap, their clinical implications, severity thresholds, and management strategies…