Baseline Laboratory Testing Before New Procedures
For most adult patients undergoing new surgical procedures or starting major medications, obtain a comprehensive metabolic panel (CMP), complete blood count (CBC), and coagulation studies (PT/INR, aPTT) as baseline testing. 1
Core Baseline Laboratory Tests
Essential Tests for All Patients
Complete Blood Count (CBC) with differential and platelet count should be obtained to assess for anemia, infection, and bleeding risk before procedures with significant hemorrhage risk 1
Comprehensive Metabolic Panel (CMP) including:
Coagulation profile (PT/INR, aPTT) for procedures with bleeding risk 1, 4
Additional Baseline Tests Based on Clinical Context
Urinalysis is required prior to surgical intervention, particularly for urological procedures 1
Pregnancy test for all women of childbearing potential before surgery or starting teratogenic medications 1, 3
Thyroid-stimulating hormone (TSH) to identify remediable causes of metabolic dysfunction 1, 2
Electrocardiogram (ECG) for cardiovascular baseline assessment 1
Risk-Stratified Additional Testing
For Patients with Specific Risk Factors
Infectious disease screening should include:
- Tuberculosis screening (QuantiFERON-TB Gold or tuberculin skin test) for patients starting immunosuppressive therapy, those with prior TB exposure, or from high-prevalence regions 1, 3
- Hepatitis B and C serologic testing for patients with injection drug use history, foreign birth in Asia or Africa, or HIV infection 1
- HIV testing with counseling for all patients with tuberculosis or relevant risk factors 1
Cardiac assessment requires:
- Echocardiogram or cardiac scan for patients receiving anthracyclines, those with prior cardiac history, prior anthracycline exposure, cardiac symptoms, or elderly patients 1
- Lactate dehydrogenase (LDH) as a prognostic marker in certain malignancies 1
Specialized testing for specific procedures:
- Visual acuity and red-green color discrimination testing when ethambutol will be used 1
- Disseminated intravascular coagulation panel (D-dimer, fibrinogen, PT, aPTT) for hematologic malignancies 1
- Tumor lysis syndrome panel (LDH, uric acid, potassium, phosphates, calcium) for patients with high tumor burden 1
Important Clinical Caveats
Routine preoperative medical testing is NOT indicated for healthy patients undergoing cataract surgery or other low-risk procedures, as large randomized trials demonstrate no reduction in perioperative morbidity or mortality 1
Timing considerations are critical:
- Protein C, Protein S, and Antithrombin III levels are consumed during acute thrombosis and will be falsely low; ideally test 2-4 weeks after acute events if hypercoagulability assessment is needed 4
- Anticoagulation therapy affects coagulation testing and may require delayed testing or specialized interpretation 4
Avoid common pitfalls:
- Do not rely solely on prolonged PT/INR and aPTT to assess thrombotic risk in cirrhosis patients, as these may paradoxically be associated with increased thrombosis risk 4
- Baseline tests establish values before medication initiation and help screen for secondary causes of disease, but should not delay urgent interventions 1, 2
- For patients with severe systemic diseases (chronic obstructive pulmonary disease, poorly controlled hypertension, recent myocardial infarction, unstable angina, poorly controlled heart failure, or poorly controlled diabetes), consider preoperative medical evaluation by primary care physician 1
Vaccination Status
Review vaccination status and administer needed vaccinations, particularly live vaccines, prior to starting B-cell depleting therapy or other immunosuppressive treatments, as these therapies may reduce vaccine effectiveness 3