Viscoelastic tests are not transfusion orders
A viscoelastic test result should change your clinical question, not bypass clinical judgment. The same abnormal value can mean different things depending on timing, bleeding pattern, CPB status, physiology, and the surgical field.
Key points
- VET results are clinical signals, not automatic transfusion orders.
- The same abnormal value may mean different things depending on timing, bleeding pattern, CPB status, physiology, and surgical field.
- The action is targeted correction followed by reassessment, not reflex product administration.
When to use this page
Whenever a viscoelastic test result is about to drive a product decision — to keep the result anchored to the clinical situation, the surgical field, and physiology.
Why this distinction matters
Viscoelastic tests are powerful because they organize bleeding patterns quickly. The risk is treating the screen instead of the patient: product therapy without source control or physiology correction may fail even when the trace appears to improve.
What VET can help with
- Fibrinogen contribution to clot strength
- Platelet contribution to clot strength
- Clotting time, factor-sensitive, or heparin-sensitive patterns
- Lysis signals
- Reassessment after targeted treatment
What VET cannot decide alone
- Whether a surgical source is bleeding
- Whether a product is always indicated
- Whether a normal-looking trace excludes bleeding
- Whether local product availability or institutional protocol supports a specific action
A value does not mandate transfusion
Interpret a VET pattern against the clinical situation. A near-normal trace does not exclude bleeding, and an abnormal value does not by itself mandate a product. The result narrows the question — it does not replace surgical field confirmation, physiology, or local protocol.
An action frame
- Identify the bleeding pattern
- Inspect the surgical field
- Interpret the VET pattern with timing and physiology
- Choose a targeted intervention only when supported
- Reassess the test and the bleeding after intervention
- Escalate to source control if bleeding persists
Platform-specific caution
ROTEM, TEG, and Quantra use different channels and terminology. Do not force one platform's number into another platform's meaning, and avoid oversimplified equivalences between their parameters.
Take-home message
A VET result should change your clinical question, not bypass clinical judgment. Interpret the pattern, act selectively, and reassess the patient.
Clinical content by Kozo Watanabe, MD View profile →
Verify your decision
Before a VET result drives a product decision → use the ROTEM trigger guide to organize the pattern, then confirm the surgical field, correct physiology, and reassess after any targeted treatment.
Open the ROTEM trigger guide →Continue learning
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