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Asmaa A: Common Sources of Error in ESR Testing
Asmaa A/LinkedIn
Oct 25, 2025, 07:41

Asmaa A: Common Sources of Error in ESR Testing

Asmaa A, DHA Medical Laboratory Technologis at Al-Ahrar International Hospital, shared a post on LinkedIn:

”ESR (Erythrocyte Sedimentation Rate): Sources of Errors — Increased and Decreased

Even a simple test like ESR can give misleading results if technical or sample-related factors aren’t right.
Here’s what can falsely decrease or increase ESR.

Falsely Decreased ESR

  • Abnormal RBC morphology (sickle cells, spherocytes, anisocytosis) → prevents rouleaux formation.
  • Polycythemia / Increased blood viscosity → RBCs settle slower.
  • Clotted or partially clotted sample → false low ESR.
  • Underfilled tube (excess anticoagulant ratio) → alters plasma/RBC balance, lowering ESR.
  • Old blood sample → shape changes (spherocytes) reduce sedimentation.
  • Low storage temperature → slows down the sedimentation rate.
  • Vibration or shaking of the tube (e.g. near centrifuge) → may falsely decrease ESR by disturbing RBC settling.

Falsely Increased ESR

  • Hemolyzed sample → may cause unreliable or falsely high results.
  • Anemia (low RBC count) → less crowding, faster fall.
  • Tube not vertical or tilted → increases ESR.
  • High room temperature → increases sedimentation rate.
  • Delay in testing (>2 hrs after collection) → RBC shape changes increase rouleaux formation.
  • Overfilled tube (insufficient anticoagulant) → ↑ Falsely high ESR

Sometimes the issue isn’t the patient it’s the sample handling!
Always check pre-analytical factors before trusting the numbers.”

 

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anemia Asmaa A Blood Sample blood viscosity Centrifuge Erythrocyte Sedimentation Rate ESR Health Hematology Hemolyzed Sample Hemostasis Hemostasis Today Laboratory Medicine POLYCYTHEMIA RBC Morphology
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