What test should be ordered to evaluate bleeding time?

Bleeding Time Testing: Current Clinical Approach

The bleeding time test is no longer recommended as a routine clinical test and has been largely abandoned in modern practice; instead, order PT/INR, aPTT, platelet count, and consider viscoelastic testing (TEG/ROTEM) or specialized platelet function assays based on the clinical scenario. 1

Why Traditional Bleeding Time Testing Is Obsolete

The cutaneous bleeding time test, historically performed with devices like Simplate II or Surgicutt, has fallen out of favor for several critical reasons:

• PT and aPTT were not designed to monitor coagulation deficiencies during hemorrhage, and traditional coagulation tests have significant limitations in predicting bleeding risk 1
• The utility of bleeding time in predicting bleeding risk is uncertain and generally not supported by available literature 1
• Bleeding time has low sensitivity for diagnosing mild platelet dysfunction, even when platelet aggregation studies show pathologic results 2
• The test requires a highly motivated and experienced operator who understands the many variables influencing results 3

Modern Alternatives: What to Order Instead

For Initial Hemostatic Evaluation

• Order PT/INR and aPTT as first-line screening tests to evaluate the extrinsic/common pathways (PT) and intrinsic/common pathways (aPTT) 4
• Order complete blood count with platelet count to assess for thrombocytopenia 1
• Order fibrinogen level to evaluate fibrinogen contribution to clot formation 1
• Verify anticoagulant exposure immediately, as this is the most common reversible cause of coagulation abnormalities 5

For Active Bleeding or Major Hemorrhage

• Viscoelastic testing (TEG or ROTEM) is strongly recommended to guide transfusion decisions in real-time 1
• These tests provide rapid turnaround time and represent a more global reflection of coagulation status compared to traditional tests 1
• TEG/ROTEM can detect hyperfibrinolysis and assess platelet function, which conventional tests miss 1
• Point-of-care testing for hemoglobin (blood gas analysis or HemoCue) correlates well with laboratory measurements 1

For Specific Clinical Scenarios

Cardiac surgery patients:

• Use viscoelastic testing to guide transfusion protocols 1
• Consider platelet function analysis only in patients who have taken P2Y12 receptor inhibitors (like clopidogrel) within 5 days of surgery 1
• Activated clotting time (ACT) should be used routinely whenever heparin is administered 1

Patients on anticoagulants:

• For dabigatran: Order dilute thrombin time, ecarin clotting time, or thrombin time (TT) for qualitative assessment 1
• For Factor Xa inhibitors (rivaroxaban, apixaban, edoxaban): Order anti-FXa assay calibrated with the specific drug 1
• Do not assume normal PT/APTT excludes clinically relevant DOAC levels, as these tests have variable sensitivity 1, 5

Obstetric patients:

• TEG/ROTEM can be used to evaluate hypercoagulability in pregnancy and guide management of obstetric hemorrhage 1
• PT ratio and aPTT ratio ≥1.5 should be used as the cut-off for coagulopathy in pregnancy rather than absolute values 4

Critical Pitfalls to Avoid

• Never use bleeding time as a preoperative screening test alone - it should be combined with aPTT if used at all, as it usually does not recognize patients with coagulopathies 3
• Do not empirically transfuse FFP in asymptomatic patients without bleeding or planned procedures, as routine correction is not recommended 5
• Recognize that INR should never be used to interpret PT results in patients on DOACs, as the INR scale was specifically designed for vitamin K antagonists only 4
• Traditional tests like PT/INR have slow turnaround times and do not reflect the dynamic clinical situation during ongoing hemorrhage 1

When Specialized Testing May Be Warranted

• Platelet aggregation studies in platelet-rich plasma may be considered for suspected inherited platelet disorders, though they do not permit etiologic diagnosis except for well-defined membrane glycoprotein deficiencies 2
• 50:50 mixing study with normal plasma should be performed if PT or aPTT is prolonged to distinguish factor deficiency from inhibitors 5, 4
• Consider thromboelastography for assessing indices of hyperfibrinolysis and platelet function when more global measures of hemostasis are needed 1