What information should be included in a hematology referral for anticoagulation therapy reassessment?

How to Write a Hematology Referral for Anticoagulation Therapy Reassessment

A hematology referral for anticoagulation reassessment should include the indication for anticoagulation, current regimen with dosing, bleeding and thrombotic risk assessments, recent bleeding events or complications, complete medication list with drug interactions, renal and hepatic function, and the specific clinical question requiring specialist input.

Essential Components of the Referral

Patient Demographics and Current Anticoagulation Status

• Document the patient's age, weight, and renal function (calculated creatinine clearance using Cockcroft-Gault formula), as these directly affect anticoagulant dosing and bleeding risk 1, 2
• State the current anticoagulant agent, dose, frequency, and duration of therapy 2
• Include the original indication for anticoagulation (e.g., atrial fibrillation, venous thromboembolism, mechanical valve) 1

Thrombotic Risk Assessment

• For atrial fibrillation patients, calculate and report the CHA₂DS₂-VASc score (Congestive heart failure, Hypertension, Age ≥65=1 point/≥75=2 points, Diabetes, prior Stroke/TIA=2 points, Vascular disease, Sex category) 1
• For VTE patients, specify whether the event was provoked or unprovoked, and document any chronic risk factors for recurrence 1, 2
• Note any mechanical heart valves or valvular atrial fibrillation, which necessitate specific anticoagulant choices 1, 2

Bleeding Risk Assessment and History

• Calculate a validated bleeding risk score such as HAS-BLED (Hypertension, Abnormal renal/liver function, Stroke, Bleeding history, Labile INR, Elderly >65, Drugs/alcohol) 1, 3
• Document any prior bleeding events while on anticoagulation, including the site (gastrointestinal, intracranial, other), severity, and date 1
• List specific bleeding risk factors: history of gastrointestinal bleeding, severe anemia, recent myocardial infarction, liver disease, thrombocytopenia, prior stroke, frequent falls, or alcohol abuse 1, 2

Complete Medication Review

• List all concomitant medications, particularly those affecting CYP3A4 and P-glycoprotein pathways (e.g., verapamil, diltiazem, antifungals, proton pump inhibitors) 1, 2
• Document antiplatelet agents (aspirin, clopidogrel, ticagrelor), as combination therapy significantly increases bleeding risk 1, 2
• Note NSAIDs and dietary supplements, which potentiate bleeding when combined with anticoagulants 1, 2

Laboratory Data

• Provide recent complete blood count with hemoglobin and platelet levels 2
• Include baseline coagulation studies: PT/INR and aPTT 2
• Report serum creatinine with calculated creatinine clearance (CrCl), as renal function is critical for dosing direct oral anticoagulants 1, 2, 4
• For warfarin patients, document time in therapeutic range (TTR), which should be at least 65% 1
• Include liver function tests if hepatic impairment is suspected 2

Recent Clinical Events Requiring Reassessment

• Detail any recent bleeding complications, including location, severity (major vs minor), interventions required, and whether anticoagulation was held or reversed 1
• Document any recent thrombotic events despite anticoagulation 1
• Note upcoming surgical or invasive procedures that may affect anticoagulation management 1, 2
• Report any new diagnoses affecting anticoagulation decisions (e.g., cancer, new cardiovascular disease) 1

Specific Clinical Question for Hematology

• Clearly state the reason for referral: continuation vs discontinuation of anticoagulation, switching agents, dose adjustment, management after bleeding event, or perioperative anticoagulation planning 1
• For post-bleeding referrals, specify whether the bleeding source was identified and corrected, and the time elapsed since the event 1
• For patients with recurrent VTE, document whether this occurred on or off anticoagulation 1

Patient-Specific Factors

• Assess and document the patient's mobility status and fall risk 2
• Note the patient's ability to afford medications and adhere to monitoring schedules 2
• Document any patient preferences or concerns about anticoagulation therapy 1, 2
• Include quality of life considerations that may impact treatment decisions 1, 2

Common Pitfalls to Avoid

Incomplete Risk Assessment

• Do not refer without calculating formal thrombotic and bleeding risk scores, as these guide specialist decision-making 1, 2
• Avoid omitting details about modifiable bleeding risk factors (uncontrolled hypertension, concurrent antiplatelet therapy, alcohol use), as these can be addressed to reduce bleeding risk 1, 2

Inadequate Medication Documentation

• Never send a referral without a complete medication list, as drug interactions are a major cause of anticoagulant-related complications 1, 2
• Do not forget to document over-the-counter medications and supplements 1

Missing Laboratory Data

• Avoid referring without recent renal function testing, as this is essential for safe anticoagulant dosing, particularly for direct oral anticoagulants 1, 2, 4
• For patients on rivaroxaban or apixaban with CrCl <30 mL/min, note that limited data exist and close monitoring is required 4

Unclear Clinical Question

• Do not write vague referrals asking to "evaluate anticoagulation" without specifying the clinical concern or decision point 1
• Avoid failing to mention the urgency of the consultation (routine vs urgent for active bleeding or imminent procedure) 1

Timing Considerations

• For patients with recent bleeding, document whether sufficient time has passed to consider restarting anticoagulation based on the bleeding site 1
• Note that gastrointestinal bleeding patients who resume anticoagulation have lower risk of thromboembolism and death despite increased rebleeding risk 1
• For intracranial hemorrhage, recognize this is the most feared complication and requires careful specialist input before restarting 1