Blood Tests Before Tooth Extraction
For most patients undergoing routine tooth extraction, no blood tests are required unless they are taking anticoagulants like warfarin, in which case an INR (International Normalized Ratio) test is mandatory and should be performed within one week before the procedure. 1
Patients NOT on Anticoagulation
For healthy patients without bleeding disorders or anticoagulant therapy:
- No routine blood tests are necessary before simple tooth extraction 1
- Standard dental extractions can proceed without laboratory evaluation in patients with normal medical history 1
Patients on Warfarin (Coumadin)
The INR is the only essential blood test required before tooth extraction in anticoagulated patients. 1
Timing and Target INR Values
- Check INR within the week before the procedure to ensure it is within therapeutic range 1
- Proceed with extraction if INR ≤3.5 without stopping warfarin 1
- Do NOT proceed if INR >3.5 - defer the procedure and contact the patient's anticoagulation clinic 1
- For most patients, the therapeutic INR range is 2.0-3.0, and extraction can safely proceed within this range 1
Critical Management Points
- Continue warfarin therapy for low-risk procedures like tooth extraction - do not stop the medication 1
- If INR is above therapeutic range but <5.0, reduce the warfarin dose until INR returns to therapeutic range, then proceed 1
- Ensure adequate local hemostatic measures (pressure, packing, sutures, tranexamic acid rinses) are available, as bleeding risk is increased even with therapeutic INR 1
Patients on Direct Oral Anticoagulants (DOACs)
For patients on apixaban, rivaroxaban, dabigatran, or edoxaban:
- Routine coagulation tests (PT/INR, aPTT) are NOT useful for monitoring DOACs and should not be ordered for routine dental procedures 1
- No blood tests are required before simple tooth extraction if the patient took their last DOAC dose >24 hours before the procedure 2
- Specialized DOAC quantitation assays (anti-FXa for rivaroxaban/apixaban, dilute thrombin time for dabigatran) are only needed for major bleeding events or high-risk surgeries, not routine dental extractions 1
Timing Recommendations for DOACs
- For simple tooth extraction, skip the morning dose on the day of the procedure and resume the evening dose after achieving hemostasis 2
- For patients with normal renal function undergoing minor procedures, no extended discontinuation is needed 2
Additional Blood Tests (Only in Specific Circumstances)
The following tests are NOT routinely required but may be considered in specific high-risk scenarios:
- Complete Blood Count (CBC) - only if there is clinical suspicion of anemia, thrombocytopenia, or hematologic disorder 3
- Renal function (creatinine clearance) - only relevant if patient is on dabigatran and there is concern about drug accumulation affecting bleeding risk 2
- Liver function tests - only if there is known liver disease that could affect coagulation factor synthesis 3
Common Pitfalls to Avoid
- Do NOT routinely stop warfarin for tooth extraction - the thrombotic risk outweighs bleeding risk when INR is therapeutic 1
- Do NOT order PT/INR for patients on DOACs - these tests do not reliably reflect DOAC activity and will lead to misinterpretation 1
- Do NOT proceed with extraction if INR >3.5 without first optimizing anticoagulation 1
- Do NOT order "routine preoperative labs" (CBC, comprehensive metabolic panel) for healthy patients undergoing simple dental extraction - this is unnecessary and not evidence-based 1
Algorithm for Decision-Making
Is the patient on warfarin?
- Yes → Order INR within one week of procedure 1
- No → Proceed to step 2
Is the patient on a DOAC (apixaban, rivaroxaban, dabigatran, edoxaban)?
- Yes → No blood tests needed; coordinate timing of last dose 2
- No → Proceed to step 3
Does the patient have a known bleeding disorder, liver disease, or hematologic condition?
If INR was ordered, is it ≤3.5?