Laboratory Workup for Bleeding Patients

First-Line Laboratory Tests

• The American Society of Hematology recommends a complete blood count with platelets and peripheral smear, PT/INR, aPTT, and fibrinogen level as first-line tests for patients presenting with bleeding 1, 2, 3
• A complete blood count (CBC) with platelets and peripheral blood smear is essential to evaluate for thrombocytopenia and abnormal platelet morphology in patients with bleeding 1, 3
• Prothrombin time (PT/INR) is used to assess the extrinsic coagulation pathway in patients with bleeding 1, 3
• Activated partial thromboplastin time (aPTT) is used to evaluate the intrinsic coagulation pathway in patients with bleeding 1, 3
• Fibrinogen level (Clauss method) is used to assess for fibrinogen disorders in patients with bleeding 1, 2
• Von Willebrand factor antigen (VWF:Ag), VWF ristocetin cofactor activity (VWF:RCo), and Factor VIII coagulant activity should be included in first-line testing for 84% of bleeding evaluations to establish VWD diagnosis, type, and severity 1, 3, 4
• ABO blood group testing is recommended as blood type O patients have 60-70% lower VWF levels than type AB 4
• Iron studies are recommended to evaluate for chronic blood loss in patients with bleeding 4

Second-Line Testing

• Intrinsic pathway factors (FVIII, FIX, and FXI assays) should be tested if first-line tests are normal but bleeding history is convincing 4
• Extrinsic pathway factors (FII, FV, FVII, and FX assays) should be tested if first-line tests are normal but bleeding history is convincing 2, 4
• Factor XIII activity is frequently overlooked but clinically important and should be tested if first-line tests are normal but bleeding history is convincing 2
• Light transmission aggregometry with multiple agonists (ADP, collagen, epinephrine, ristocetin, arachidonic acid) is recommended for patients with mucocutaneous bleeding 2, 4
• Platelet flow cytometry is recommended to evaluate platelet surface glycoproteins and activation markers in patients with bleeding 2
• PFA-100/200 testing is an alternative platelet function screen for patients with bleeding 4
• VWF multimer analysis should be performed if the ratio of VWF:RCo to VWF:Ag is below 0.5-0.7, or if initial VWD testing shows abnormal results 1, 2, 3

Special Considerations

• For children with easy bruising, additional tests such as serum calcium, phosphorus, and alkaline phosphatase for bone metabolism disorders are recommended 1
• For children with easy bruising, parathyroid hormone and 25-hydroxy-vitamin D tests are recommended 1
• For children with easy bruising, serum copper and ceruloplasmin tests are recommended 1
• Non-hematologic causes including connective tissue disorders, medication effects, and non-accidental trauma should be considered in pediatric patients with bleeding 1

Documentation and Follow-Up

• A structured bleeding assessment tool (ISTH-BAT or Pediatric Bleeding Questionnaire) should be used to quantify bleeding severity, as 80% of specialists use these instruments and they influence the extent of testing ordered 1, 4

Laboratory Evaluation of Bleeding Disorders – Evidence‑Based Recommendations

First‑Line Testing Panel

Additional First‑Line Assessments

Second‑Line Coagulation Factor Testing (when first‑line results are normal but bleeding persists)

Platelet Function Testing

Specialized von Willebrand Disease (VWD) Testing

Pre‑Analytical Considerations for Platelet Function Tests

Interpretation When All First‑Line Tests Are Normal

Referral to a Hemostasis Specialist

Key Clinical Indicators for Laboratory Evaluation of Frequent Epistaxis

Clinical History Factors that Prompt Hematologic Testing

• Episodes lasting more than 30 minutes within a 24‑hour period are associated with severe epistaxis and warrant further laboratory work‑up. 7, 8
• A history of hospitalization, blood transfusion, or > 3 recent nosebleed episodes signals significant bleeding and should trigger comprehensive testing. 7, 8
• A positive family history of recurrent nosebleeds suggests a hereditary bleeding disorder and guides the decision to obtain hematologic studies. 7
• Presence of comorbid conditions (e.g., hypertension, cardiopulmonary disease, anemia, known bleeding disorders, liver or kidney disease) influences the need for laboratory evaluation. 7, 8
• Use of anticoagulant or antiplatelet medications is an important modifier of bleeding severity and indicates that laboratory assessment is appropriate. 7, 8

Assessment of Medication, History, and Renal Function in Elderly Patients with Bruising

Medication Review

• A comprehensive medication review—including anticoagulants (e.g., warfarin, heparin), antiplatelet agents (e.g., aspirin, clopidogrel), supplements, and other chronic drugs—is essential because these agents can alter coagulation pathways and platelet function, particularly in patients aged 70 years and older. 9

Personal and Family Bleeding History

• Obtaining a detailed personal and familial history of prior bleeding events, transfusions, or known congenital coagulopathies is crucial for interpreting laboratory results and guiding further hemostatic evaluation. 9

Renal Function Assessment

• Evaluation of renal function should be performed, as renal insufficiency may impair platelet activity and contribute to abnormal bleeding tendencies in the elderly. 9

Assessment and Laboratory Evaluation of Suspected Bleeding Disorders

Clinical Assessment

• The International Society on Thrombosis and Haemostasis (ISTH) recommends using a validated bleeding assessment tool such as the ISTH‑Bleeding Assessment Tool (BAT) to objectively quantify bleeding severity; 73 % of hematology specialists employ this tool in practice. 10
• Recording detailed mucocutaneous bleeding patterns—including unexplained bruising, epistaxis lasting longer than 30 minutes, heavy menstrual bleeding, bleeding during childbirth, postoperative bleeding, and bleeding after dental procedures—helps identify patients who merit further hemostatic work‑up. 10
• A thorough family history of bleeding disorders is obtained by 98 % of specialists and markedly raises the pre‑test probability of an inherited bleeding condition. 10
• Physical examination should include evaluation for syndromic features (e.g., hearing loss, cardiac anomalies, distinctive facial or skeletal dysmorphisms, ocular findings, neurodevelopmental delay, skin discoloration) that may point toward specific inherited platelet‑function disorders. 10
• Assessment for eczema, recurrent infections, or neutrophil abnormalities can uncover associated immunologic conditions such as Wiskott‑Aldrich syndrome. 10

First‑Line Laboratory Testing

• A complete blood count with platelet count and peripheral smear is performed by 100 % of specialists to detect thrombocytopenia, abnormal platelet size or morphology, and other hematologic abnormalities (e.g., abnormal red‑cell or neutrophil morphology). 10

Second‑Line Testing (When First‑Line Results Are Normal but Bleeding Persists)

• Light transmission aggregometry (LTA) using multiple agonists (ADP, collagen, epinephrine, ristocetin, arachidonic acid) is considered the gold‑standard method for diagnosing inherited platelet‑function defects; it is utilized by 60 % of specialists. 10
• An impaired aggregation response to arachidonic acid on LTA suggests defects in the cyclo‑oxygenase‑1 pathway, thromboxane synthesis, P2Y12 signaling, or conditions such as Glanzmann thrombasthenia. 10
• Abnormal aggregation with ristocetin indicates either platelet‑type von Willebrand disease or Bernard‑Soulier syndrome. 10
• Isolated defective response to epinephrine on LTA is a common finding in routine screens and should prompt further investigation only when accompanied by additional abnormalities or a strong clinical suspicion of a platelet disorder. 10
• Platelet granule release assays (e.g., ATP/ADP secretion measured by lumi‑aggregometry or HPLC, and α‑granule marker assessment by ELISA or flow cytometry) are employed to detect storage‑pool deficiencies. 10

Laboratory Evaluation of New‑Onset Bruising

Initial Hemostasis Panel

• In adult patients with unexplained bruising, 100 % of hematology specialists order a complete blood count with platelet count and peripheral smear to identify thrombocytopenia or abnormal platelet morphology. 11

Liver Function Assessment

• When physical examination reveals signs suggestive of hepatic disease (e.g., jaundice or splenomegaly), liver function tests are recommended as part of the first‑line work‑up. [11][12]

Documentation of Personal Bleeding History

• A detailed bleeding history—including epistaxis lasting >30 minutes, heavy menstrual bleeding, postoperative or dental procedure bleeding, and prior transfusions—is essential for guiding further testing. 11

Physical Examination Indicators

• The presence of ecchymoses, hematomas, or petechiae on examination signals an active bleeding disorder and warrants laboratory investigation. [11][12]13

Pre‑Analytical Considerations for VWF Testing

• To avoid falsely elevated von Willebrand factor (VWF) and Factor VIII levels, patients should be kept calm during venipuncture; anxiety or crying can increase these values by 25‑50 %. 14
• Use of oral contraceptives or estrogen therapy raises VWF levels and must be recorded before testing. 14
• Blood samples for VWF assays should be kept at room temperature, plasma separated promptly at room temperature, and frozen at ≤ ‑40 °C if analysis is delayed beyond 2 hours. 14

Interpretation of VWF Ratios and Multimer Analysis

• A VWF ristocetin cofactor (VWF:RCo) to VWF antigen (VWF:Ag) ratio < 0.5‑0.7 indicates a qualitative (Type 2) von Willebrand disease and prompts reflex VWF multimer analysis. [11][13]
• VWF multimer analysis is reserved for cases with an abnormal VWF:RCo/VWF:Ag ratio or other abnormal initial VWF results; it is not part of routine initial screening. [11][13]

Guideline Recommendations for VWD Testing

• The National Heart, Lung, and Blood Institute (NHLBI) issues a Grade B recommendation for ordering the VWF antigen, VWF ristocetin cofactor activity, and Factor VIII activity panel when a strong bleeding history or mucocutaneous symptoms are present. 11

Mixing Study for Isolated aPTT Prolongation

• When only the activated partial thromboplastin time (aPTT) is prolonged, a mixing study should be performed to differentiate a true factor deficiency from the presence of an inhibitor. 14