What blood work is recommended for a patient with a pulmonary mass, possible metastasis, and weight loss?

Recommended Blood Work for Pulmonary Mass with Possible Metastasis and Weight Loss

For a 46-year-old patient with a pulmonary mass, possible metastasis, and weight loss, obtain a complete blood count (CBC), comprehensive metabolic panel (including liver function tests, serum calcium, and lactate dehydrogenase), and consider alkaline phosphatase if bone metastases are suspected. 1

Essential Laboratory Tests

Core Blood Work Panel

• Complete blood count (CBC) to assess for anemia, which is common in metastatic lung cancer 1
• Comprehensive metabolic panel including:
  • Liver function tests (AST, ALT, bilirubin, albumin) 1
  • Serum calcium level (elevated in bone metastases) 1
  • Lactate dehydrogenase (LDH) as a prognostic marker 1
  • Serum creatinine to assess renal function 1

Additional Tests Based on Clinical Suspicion

• Alkaline phosphatase if bone pain or bony tenderness is present, as elevation suggests skeletal metastasis 1
• Coagulation profile if invasive procedures are planned 1

Clinical Context for Laboratory Interpretation

Symptoms Indicating Metastatic Disease

The combination of weight loss with a pulmonary mass is concerning for advanced disease, as patients with distant metastases often present with nonspecific systemic symptoms including anorexia, weight loss, and fatigue 1, 2. These systemic symptoms are associated with worse prognosis even within the same cancer stage 2.

Site-Specific Laboratory Abnormalities

• Liver metastases (common in lung cancer) often present with weakness and weight loss, but liver function tests typically remain normal until liver involvement is very advanced 1, 2
• Bone metastases occur in 6-25% of patients at presentation and may cause elevation of serum calcium or alkaline phosphatase 1, 2
• Adrenal metastases are typically asymptomatic and rarely cause adrenal insufficiency 1, 2

Important Diagnostic Considerations

Imaging Takes Priority Over Blood Work

While blood work is important, the American College of Chest Physicians recommends CT chest with contrast as the foundational imaging study for all patients with known or suspected lung cancer 3. The CT should be extended to include liver and adrenal glands if PET scan is unavailable 3.

Tissue Diagnosis is Essential

Blood work alone cannot establish the diagnosis. For patients with systemic symptoms suggesting metastatic disease, biopsy of a metastatic site can efficiently establish both diagnosis and stage 1, 2. The least invasive method should be selected based on the patient's presentation 1, 3.

Common Pitfalls to Avoid

• Do not rely solely on liver function tests to exclude liver metastases, as they remain normal until advanced involvement 1, 2
• Do not delay tissue diagnosis while waiting for blood work results, as establishing histologic type and molecular characterization is paramount for treatment planning 1
• Consider that weight loss may indicate either primary lung cancer or metastatic disease from another primary site, particularly in patients over 55 who smoke 4