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Sifat Jubaira: Effect of Prolonged Tourniquet Application

Sifat Jubaira/LinkedIn

Feb 2, 2026, 17:16

Sifat Jubaira: Effect of Prolonged Tourniquet Application

Sifat Jubaira, Lab Medicine Specialist at United Hospital Limited, shared a post on LinkedIn:

“Effect of Prolonged Tourniquet Application

Prolonged tourniquet application (typically >1 minute) causes venous stasis, leading to hemoconcentration and localized metabolic changes. This is a well-documented pre-analytical error.

Proven Laboratory Effects

Falsely Increased

Total protein, Albumin
Calcium (protein-bound fraction)
Hemoglobin, Hematocrit
RBC, WBC, Platelet counts
Potassium (especially with fist clenching)
Lactate
AST, CK

Falsely Decreased

Glucose (local cellular uptake)
pH (local acidosis)

Why this happens?

Venous stasis causes plasma water to shift into interstitial space, while cells and large molecules remain intravascular → concentration effect.

Why it matters?

Pseudohypercalcaemia
Misinterpretation of dehydration
Unnecessary repeat testing or inappropriate clinical decisions

Best-Practice Recommendation

Apply tourniquet for ≤ 1 minute
Release as soon as blood flow is established
Avoid fist clenching

If delay occurs, release and reapply after 2 minutes.

Authoritative Sources

CLSI GP41-Ed7 (2020)
Collection of Diagnostic Venous Blood Specimens.
WHO Guidelines on Drawing Blood (2010).
McPherson & Pincus. Henry’s Clinical Diagnosis and Management by Laboratory Methods, 23rd ed.
Lippi G et al. Preanalytical variability in laboratory testing. Clin Chem Lab Med.

Pre-analytical accuracy is patient safety.

Sifat Jubaira: Effect of Prolonged Tourniquet Application