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Semin Thromb Hemost 2024; 50(03): 517-519
DOI: 10.1055/s-0043-1776877
Historical Commentary

The Bleeding Time Test in 2024: A Glorious Past and Current Challenges

Anetta Undas 
1   Department of Thromboembolic Diseases, Institute of Cardiology, Jagiellonian University Medical College, Krakow, Poland
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A Critical Reappraisal of the Bleeding TimeSemin Thromb Hemost 2024; 50(03): 499-516
DOI: 10.1055/s-0043-1777307

A Critical Reappraisal of the Bleeding Time

The bleeding time has been used in clinical practice for more than 100 years, with the highest number of measurements performed between 1970 and 2000 worldwide. The bleeding time is measured largely using the approach by Mielke et al,[1] mostly with commercially available devices (e.g., Simplate and Surgicutt) based on the assay introduced by Mielke et al,[1] in which standardized skin incisions are performed on a forearm with the use of a sphygmomanometer cuff to maintain a standard venous pressure. The bleeding time test was long considered as the best clinically available comprehensive test to assess primary hemostasis, especially platelet function. This test once represented a clinically useful test in two clinical settings: (1) diagnostic evaluation of patients suspected of platelet disorders or defects in platelet–vessel wall interactions; and (2) prediction of clinically relevant bleeding in patients undergoing invasive procedures, in particular major surgery. From a perspective of basic science research, the bleeding time was a valuable model of microvascular injury used to assess primary hemostasis at the site of plug formation as a function of time including the determination of multiple substances, especially platelet-derived factors involving thromboxane B2, platelet factor 4, β-thromboglobulin, soluble CD40 ligand, and P-selectin.[2] [3] Within bleeding time blood samples typically collected every 30 to 60 seconds, small amounts or concentrations of various blood coagulation proteins such as coagulation factors (factors II, V, XIII, fibrinogen) and coagulation inhibitors (protein C) have been determined using immunoenzymatic assays, mass spectrometry, or Western blotting to document among others drug-induced alterations to blood clotting.[4] [5] It has been shown that tissue factor-induced blood coagulation leads to thrombin generation in blood oozing from bleeding time wounds.[6] The strongest evidence shows enhanced thrombin generation following skin injury as reflected by a gradual increase in concentrations and amounts of thrombin markers (i.e., thrombin-antithrombin complexes, prothrombin fragment 1.2, and fibrinopeptide A, which reaches a plateau after 3 to 5 minutes at the sites of the bleeding time wounds).[3] [7] Moreover, plasma fibrin clot properties assessed in vitro, in particular formation of denser fibrin clots, are also associated with bleeding time, which suggests a previously unknown contribution of fibrinogen/fibrin-related mechanisms beyond platelet counts and functions.[8]

Several studies, in which the bleeding time test was used, have shown that aspirin prolongs bleeding time (though to a variable extent up to more than 100%)[1] [2] [3] and reduces local formation of thrombin and release of platelet activation markers both in healthy subjects, patients with elevated cholesterol levels as well as patients with cardiovascular diseases, without differences in the range of doses from 30 to 300 mg.[3] [5] [9] Prolongation of bleeding time has been reported in subjects receiving other antiplatelet agents for example clopidogrel.[10] Reduction of coagulation activation markers following the administration of heparins has also been demonstrated in blood obtained directly from a vascular injury site.[11] Among other agents tested at sites of hemostatic plug formation, cholesterol-lowering statins should be highlighted; this class of drugs has been shown to decrease prothrombin activation and thrombin-mediated coagulation reactions, along with enhance thrombomodulin-mediated protein C activation and resultant factor Va inactivation, and those effects have been found to be cholesterol independent.[4] The bleeding time-based microvascular injury model provided additional data on antithrombotic or precisely anticoagulant effects of cholesterol-lowering actions of statins.[12] Of note, this model based on the bleeding time test led to interesting findings on the pathophysiology of diseases associated with thromboembolic and bleeding manifestations, including acute myocardial infarction and stable coronary artery disease,[13] acute hyperglycemia,[14] the impact of factor V Leiden mutation,[15] deficiencies in coagulation factors,[6] and inherited platelet disorders (e.g., deficiencies in platelet glycoproteins).[7]

The excellent review by Rodgers and Levin,[16] published in 1990 summarized available data on the utility of the bleeding time test in clinical practice. The authors assessed 862 articles, including 664 papers in which original data on the utility of this test were shown. Rodgers and Levin[16] demonstrated that the bleeding time is prolonged following aspirin ingestion though the results were highly variable, showing a quite limited ability to discriminate subjects who take this agent from nonusers. Moreover, based on surgical studies, the authors concluded that the bleeding time was not useful in predicting abnormal bleeding. Similar findings questioning the value of this test were presented for other clinical situations such as uremia, renal biopsy, and massive transfusion.[16] The analysis confirmed that platelet count is inversely associated with the bleeding time, though they underscored the presence of several factors including test conditions (e.g., ambient temperature), diseases, other drugs taken, could affect the results of this test. The authors predicted that “The test is likely to remain widely used for the diagnosis of inherited disorders of platelet function, such as von Willebrand's syndrome, despite the lack of clear criteria for its use in this context.” Similar conclusions were drawn by Lind.[17] Subsequent years lowered the clinical value of the bleeding time measurements. In 1994 De Caterina et al[18] showed that without history of bleeding and use of nonsteroidal anti-inflammatory drugs, longer bleeding time and related parameters are not associated with perioperative and postoperative bleeding in patients undergoing coronary bypass surgery and the authors did not recommend using the bleeding time to evaluate the risk of bleeding. More recent data on the bleeding time in surgical patients provided similar disappointing observations indicating that the bleeding test displays low specificity, and it “should only be used in combination with the patient's bleeding history and careful assessment of other hematologic parameters.”[19]

What is a role of the bleeding time in 2024? At present the bleeding time test appears almost passe. There is general agreement that the sensitivity and specificity of the bleeding time for platelet-mediated disorders are unacceptably low. Poor reproducibility and scars on the skin observed in 20 and 30% of the subjects have also substantially limited the popularity of the test. The closure time generated by the means of the platelet function analyzer -100 or -200[20] [21] to diagnose platelet function disorders and von Willebrand disease has become the real-life valid alternative to the bleeding time test, though the usefulness of this newer assay is lower in some disorders (especially thrombocytopenic patients). In patients awaiting major surgery, a meticulous medical history, physical examination and basic coagulation tests are the basis of preoperative decision-making in terms of assessment of bleeding risk. To evaluate antiplatelet effects induced by various agents, standardized point-of-care platelet function devices (e.g., VerifyNow) are widely available and used in specific clinical settings (e.g., the risk of a thrombotic event despite the administration of the antiaggregatory agent at recommended doses).[22] [23] Nevertheless, in my opinion, the bleeding time test and derived vascular injury models are still of interest for research purposes to explore complex, elusive processes involved in primary hemostasis in various clinical situations.

In conclusion, after more than 30 years since the seminal review by Rodgers and Levin,[16] the bleeding time test is no longer used in everyday practice. This test cannot reliably predict the risk of hemorrhage associated with surgical or other invasive procedures or reliably assess the exposure to aspirin, antiplatelet agents, or nonsteroidal anti-inflammatory drugs. The bleeding time test was in part replaced by newer laboratory tests,[24] which are interpreted along with a detailed personal and family history, as well as a medication review. However, even now, evaluation of bleeding risk is a great challenge and the performance of available devices or assays in at-risk patients not receiving agents inhibiting platelet function remains poor. We therefore continue to await a new reproducible “bleeding test” of clinical relevance in particular for individuals undergoing invasive procedures.



Publication History

Article published online:
15 November 2023

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