What labs should be ordered for an 85-year-old female with unintentional weight loss?

Laboratory Evaluation for Unintentional Weight Loss in an 85-Year-Old Female

The recommended laboratory workup for an 85-year-old female with unintentional weight loss should include a complete blood count, comprehensive metabolic panel, thyroid function tests, urinalysis, inflammatory markers, and age-appropriate cancer screenings.

Initial Laboratory Assessment

Essential First-Line Tests

• Complete blood count (CBC) 1
• Basic metabolic panel (BMP) 1
• Liver function tests (LFTs) 1
• Thyroid function tests (TSH) 1
• Inflammatory markers:
  • C-reactive protein (CRP) 1
  • Erythrocyte sedimentation rate (ESR) 1
• Fasting glucose measurement 1
• Lactate dehydrogenase (LDH) 1
• Urinalysis 1
• Ferritin 1
• Protein electrophoresis 1

Recommended Imaging

• Chest radiography 1
• Fecal occult blood testing 1

Targeted Additional Testing Based on Initial Findings

Malignancy Evaluation

• Tumor markers if clinically indicated:
  • Carcinoembryonic antigen (CEA) 2
  • Prostate specific antigen (PSA) in males 2
  • CA 19-9 2
• Age-appropriate cancer screenings 1

Gastrointestinal Evaluation

• Consider upper endoscopy and/or colonoscopy if GI symptoms or abnormal fecal occult blood test 2
• Abdominal ultrasonography for evaluation of liver, pancreas, and other abdominal organs 3

Metabolic/Nutritional Assessment

• Vitamin B12 levels 4
• Vitamin D levels 4
• Calcium levels 4
• Albumin (to assess nutritional status) 4

Clinical Context and Interpretation

Common Etiologies to Consider

• Malignancy (accounts for up to one-third of cases) 1
• Non-malignant gastrointestinal disorders 3
• Psychiatric conditions (especially depression) 3
• Medication side effects and polypharmacy 1
• Endocrine disorders (thyroid dysfunction, diabetes) 1
• Social factors (isolation, food insecurity) 1

Important Considerations for the Elderly

• In approximately 6-28% of cases, no specific cause is identified despite thorough evaluation 1
• If initial evaluation is unremarkable, a 3-6 month observation period with follow-up is appropriate 1
• Medication review is essential as polypharmacy can affect taste and cause nausea 3
• Assessment for depression is critical, especially in long-term care residents 5

Follow-up Recommendations

• If initial testing is negative, consider more specialized testing based on specific symptoms
• Schedule follow-up in 2-4 weeks to review test results and assess weight trends
• Consider nutritional consultation for dietary modifications that account for patient preferences and any swallowing difficulties 1
• Monitor weight regularly to assess response to interventions

Common Pitfalls to Avoid

• Focusing only on malignancy when non-malignant causes are more common in the elderly 3
• Overlooking medications as potential causes of weight loss 1
• Failing to assess for depression and social factors 5
• Excessive testing without clinical indication, which can lead to incidental findings and unnecessary procedures
• Delaying nutritional intervention while pursuing diagnostic workup