What baseline laboratory examinations are recommended before starting chemotherapy?

Baseline Laboratory Examinations Before Chemotherapy

All patients should undergo comprehensive baseline laboratory testing within 7 days before initiating chemotherapy, including complete blood count with differential, comprehensive metabolic panel (renal and hepatic function), coagulation studies, and hepatitis B virus screening 1, 2, 3.

Core Laboratory Tests Required

Hematologic Assessment

• Complete blood count (CBC) with differential and platelet count 1, 2, 4
• Baseline values establish reference points for monitoring myelosuppression during treatment
• Repeat hemoglobin, hematocrit, and platelets every 2-3 days for first 14 days after starting anticoagulation if indicated, then every 2 weeks 2

Metabolic and Organ Function Panel

• Comprehensive metabolic panel including:
  • Serum electrolytes (sodium, potassium, chloride, bicarbonate)
  • Magnesium and phosphate 5
  • Renal function (creatinine, blood urea nitrogen, calculated creatinine clearance)
  • Liver function tests (AST, ALT, alkaline phosphatase, bilirubin, albumin) 1, 2, 4

Tumor Lysis Syndrome Panel (for high tumor burden)

• Lactate dehydrogenase (LDH)
• Uric acid
• Potassium, phosphate, calcium 4
• This is particularly critical for patients with hyperleukocytosis or large mediastinal masses

Coagulation Studies

• Prothrombin time (PT)/INR and activated partial thromboplastin time (aPTT) 2, 4
• Disseminated intravascular coagulation panel (D-dimer, fibrinogen) 4

Infectious Disease Screening

Mandatory Hepatitis B Testing

All patients must be tested for hepatitis B virus before any systemic anticancer therapy using three tests 3:

• Hepatitis B surface antigen (HBsAg)
• Hepatitis B core antibody (anti-HBc) total IgG or IgG
• Antibody to hepatitis B surface antigen

This is critical because HBV reactivation occurs in 33-44% of infected patients receiving chemotherapy without prophylaxis 6. Anticancer therapy should not be delayed for results, but testing must be performed 3.

HIV and Hepatitis C Testing

• Encouraged for patients with risk factors or unusual disease presentations 1, 7

Tumor Marker Assessment (Cancer-Specific)

For Germ Cell Tumors

Measure serum alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and LDH 8:

• Before any treatment (post-orchiectomy for testicular cancer)
• Immediately prior to chemotherapy for stage II/III disease
• At the start of each chemotherapy cycle

For Other Malignancies

• Tumor markers are generally not required for most solid tumors at baseline unless specifically indicated by disease type

Cardiac Assessment

Ejection Fraction Evaluation

Baseline cardiac function assessment is required for patients receiving anthracycline-based chemotherapy 1, 9, 7:

• Echocardiography (preferred when satisfactory images obtainable - provides valve function data)
• MUGA scan (higher reproducibility but involves radiation exposure)
• Use the same modality throughout treatment for consistency 9

Important caveat: For younger patients (<65 years) without cardiac risk factors receiving anthracycline-based therapy without trastuzumab, routine MUGA may not influence treatment decisions 10. However, guidelines still recommend baseline assessment 1, 7.

Additional Cardiac Workup

• 12-lead ECG looking for 9:
  • Arrhythmias (atrial fibrillation, heart block)
  • Evidence of prior myocardial infarction (Q-waves, left bundle branch block)
  • Left ventricular hypertrophy
• Blood pressure measurement (treat if ≥140/85 mmHg with ACE inhibitor) 9

Pulmonary Function Testing

For patients receiving bleomycin-based chemotherapy, obtain pulmonary function tests including diffusing capacity of the lungs for carbon monoxide (DLCO) 1, 7:

• DLCO threshold of at least 60% is generally acceptable for bleomycin use 1

Reproductive Health Considerations

Pregnancy Testing

Mandatory pregnancy test for all women of childbearing age before treatment 1, 7

Fertility Preservation Counseling

• Discuss and offer fertility preservation options (sperm cryopreservation for males, oocyte/ovarian tissue cryopreservation for females) before starting alkylating agent-based chemotherapy or pelvic radiation 1, 4, 7
• Referral to fertility preservation program should occur before chemotherapy initiation 4

Timing of Laboratory Tests

Critical timing consideration: Research demonstrates that baseline laboratory tests performed within 7 days of chemotherapy initiation detect nearly all clinically significant changes 11. The median interval in practice is 4 days 11.

• 33% of patients show meaningful changes (≥1 grade by NCI Common Toxicity Criteria) in laboratory values within 6 weeks before chemotherapy 11
• Most common changes: hemoglobin (22%), ALT (14%), WBC (11%), AST (10%) 11

Common Pitfalls to Avoid

1. Failing to check hepatitis B serology: This is frequently missed (only 17% tested in one study) but critical given 33-44% reactivation risk 6

2. Inadequate liver function testing: Only 66% of patients had liver function tests despite being standard of care 11

3. Delaying chemotherapy for test results: While testing should be comprehensive, treatment should not be delayed for results unless clinically unstable 3

4. Using different cardiac imaging modalities during treatment: This reduces reproducibility and makes trend assessment difficult 9

5. Omitting fertility counseling: This must occur before treatment initiation, not after 1, 4