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Clotting Time

A basic manual screening procedure for observing the time required for whole blood to clot under standardized conditions.

Last verified 1 month ago 1 min read Coagulation Haematology #Coagulation #Clotting Time
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Document Control
Version
1.0
Effective
Aug 31, 2026
Reviewed
Aug 28, 2026
Department
Haematology
Principle

The procedure measures the time required for whole blood to form a visible clot under defined conditions.

Purpose

To determine whole-blood clotting time using an approved manual procedure.

Principle

Whole blood is maintained under defined conditions and the time until visible clot formation is determined.

Specimen

Follow the locally approved collection procedure for the specific clotting-time method used.

Equipment and Materials

  • Approved collection or test containers
  • Validated timing device
  • Personal protective equipment

Procedure

  1. Verify patient identification.
  2. Collect or prepare the specimen using the approved procedure.
  3. Start timing according to the validated method.
  4. Observe clot formation using the approved technique.
  5. Record the clotting time.
  6. Document any procedural deviations.

Quality Control

Standardize collection, timing and environmental conditions according to the validated procedure.

Interpretation

Clotting time is a basic screening method with significant methodological limitations compared with modern coagulation testing.

Safety

Follow standard precautions and appropriate specimen-handling procedures.

Frequently Asked Questions

No. It is a basic screening method with important methodological limitations.
Procedural variation can significantly affect manual clotting-time results.