Bleeding Time, Template
The Bleeding Time (BT) was introduced as a tool for predicting the risk of bleeding in relation to
surgery. The bleeding time is an outdated screening test that was used to measure platelet
function and vascular integrity. It is a test that is no longer widely performed due to the
difficulties in standardisation and the wide intra- and inter-user variability. Under controlled
conditions an incision is made in the skin and the duration of bleeding measured using a
modified template device.
The bleeding time is a highly operator-dependent test, plagued by a lack of clinical
reproducibility, and affected by numerous technical factors such as location of the incision,
pressure applied, operator experience, and patient factors such as age, gender, diet, hematocrit,
skin laxity and medications. Over the past decade, abundant evidence has accumulated that the
bleeding time is not reliable as a screening test for perioperative bleeding or as a diagnostic test
for bleeding.
In the absence of the bleeding time, the algorithm below is recommended for evaluating a
patient's risk of excessive bleeding. The best pre-procedure screen to predict bleeding is a
careful clinical history including family, dental, obstetric, surgical, traumatic injury, transfusion,
and drug history. If the history yields no suspicion of a hemostatic problem, further testing is not
warranted. If the history is positive, the most common hemostatic disorders can be ruled out by
performing screening tests of coagulation (PT and APTT), a platelet count, and ruling out von
Willebrand's disease (Factor VIII, von Willebrand Factor Antigen, Ristocetin Cofactor). If these
tests are negative the possibility of a platelet function disorder can be investigated by
performing platelet aggregation testing.
Abnormalities:Bleeding Time Abnormalities:
 Collagen disorders: e.g. Ehlers Danlos syndrome
 Thrombocytopaenia: It is important to check the platelet count before performing a
bleeding time. A platelet count of <50 x 10/L is generally considered to prolong the BT.
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Qualitative platelet disorders:Inherited and acquired platelet disorder including the use
of anti-platelet drugs such as aspirin and clopidogrel will prolong the BT. However, the
BT cannot reliably predict the risk of peri-operative bleeding in patients taking these
drugs.
araproteinaemias can also lead to defective platelet function and may, therefore,
prolong the BT other acquired disorders of platelet function such as seen in uraemia and
the myelodysplastic syndromes (MDS) and myeloproliferative disorders (MPD) will also
prolonged the BT.
Von Willebrand Disease (VWD)A deficiency of Von Willebrand Factor (VWF) may
prolong the BT but not in all cases. The BT is no longer recommended as a test for the
diagnosis of Von Willebrand Disease (VWD)- see UKHCDO guidelines on Diagnosis of
VWD.
Severe anaemia In patients with anaemia, there is a change in the distribution of
platelets and a decreased interaction of the platelets with the vascular endothelium
resulting in a prolonged BT. Correction of the anaemia will improve the BT.
Hypofibrinogenaemia:; Fibrinogen is required for platelet-platelet interaction and the
BT will, therefore, be prolonged in cases of hypofibrinogenaemia.
Douglas A. Triplett Coagulation and Bleeding Disorders: Review and Update Clinical
Chemistry August 2000 vol. 46 no. 8 1260-1269
Stuart E. Lind The bleeding time does not predict surgical bleeding. Blood1991;77:2547552.
Giuseppe Lippi and Massimo Franchini Laboratory Screening for Abnormalities of
Primary Hemostasis What’s Next? Clinical Chemistry November 2001 vol. 47 no. 11 2071
1. The
 BT is generally considered to be normal in patients with deficiencies of
factor VIII and IX [haemophilia A or B].
2. A normal BT does not exclude a significant bleeding diathesis.