Dr. Tareq Abadl: Why Does MCV Falsely Increase When Blood Glucose Is High?
Dr. Tareq Abadl, Medical Laboratory Specialist and Director of the Blood Bank at Dr. Abdelkader Al-Mutawakkil Hospital, shared a post on LinkedIn:
“Why Does MCV Falsely Increase When Blood Glucose Is High?
When reviewing a CBC report, a high MCV (Mean Corpuscular Volume) usually makes us think of vitamin deficiencies like B12 or folate.
But hold on! If the patient has severe hyperglycemia, the MCV can appear elevated — and it’s not real. It’s simply a false increase caused by high glucose levels.
What’s the mechanism?
1. High Glucose in Plasma
When blood glucose is significantly elevated, its concentration outside the red blood cells becomes much higher than inside.
2. Osmosis Effect
Red blood cells try to balance this difference by pulling water into the cell through osmosis.
3. Temporary Cell Swelling
As water enters, the RBCs swell and become larger than normal.
4. Analyzer Interpretation
The hematology analyzer detects these swollen cells and reports a higher MCV, even though the true cell size hasn’t changed.
Key Point
This increase is falsely elevated, not a sign of a real RBC abnormality.
Once blood glucose levels normalize, the cells return to their normal size, and the MCV value drops back to baseline.”

More posts from Dr. Tareq Abadl on Hemostasis Today.
-
Aug 23, 2026, 17:51Gurpreet Kaurr: A Proud Milestone in Haematology and Oncology
-
Aug 23, 2026, 17:33Kathrine Kaspersen: How Voluntary Plasma Donors Helped Transform Denmark’s Plasma Supply
-
Aug 23, 2026, 16:51Sthanu Subramanian: Empagliflozin and a Rise in Hematocrit
-
Aug 23, 2026, 16:50Lale Tokgözoğlu: New PCSK9i Research Published in the European Heart Journal
-
Aug 23, 2026, 16:44Eric Gehrie: Your 2026 Guide to the Essentials of Transfusion Medicine
-
Aug 23, 2026, 16:35Thomas Dayspring: The Overlooked Pathway in Cholesterol Homeostasis
-
Aug 23, 2026, 16:28Evan Mapelu: The People Who Make Cancer Care Meaningful
-
Aug 23, 2026, 16:09Felice Gragnano: New Publication on Aspirin Discontinuation After PCI for Acute Coronary Syndromes
-
Aug 23, 2026, 16:06Mostafa Faisal: Donor Type and Long-Term Quality of Life After HCT for Severe Aplastic Anemia