Blood thickness test: what it means

A full blood count assesses red cells, white cells and platelets. Clotting tests assess how blood forms a clot and may be requested before a procedure or when bleeding or clotting is suspected. In selected situations, a laboratory may assess plasma viscosity. The right test depends on your symptoms, medicines and medical history; the phrase blood thickness does not identify a diagnosis.

Ask which test has been ordered and whether fasting or medicine instructions apply. Tell the clinician about anticoagulants, bleeding, easy bruising, recent illness and family history of clotting problems. Do not stop prescribed medicine unless the prescriber gives clear instructions. A result may lead to repeat testing or another examination rather than immediate treatment.

Seek emergency help for sudden breathlessness, chest pain, coughing blood, one-sided weakness, trouble speaking or a painful swollen limb. Get prompt advice for uncontrolled bleeding, black stools, vomiting blood or a sudden severe headache. These symptoms need urgent assessment regardless of a previous test result.

Ask what the test is measuring, why it was selected and whether any medicine should be adjusted. Clarify when results are expected, what symptoms should trigger urgent help and whether further tests are planned.