From the Guidelines
Laboratory tests for unintentional weight loss should include a comprehensive metabolic panel (CMP), complete blood count (CBC), thyroid function tests (TSH, free T4), inflammatory markers (ESR, CRP), urinalysis, and fasting glucose, as recommended by the most recent guidelines 1. The initial workup for unintentional weight loss should be guided by the patient's age, risk factors, and associated symptoms.
- A comprehensive metabolic panel (CMP) and complete blood count (CBC) are essential to evaluate for underlying metabolic and hematological disorders.
- Thyroid function tests (TSH, free T4) are crucial to diagnose thyroid disorders, which are common causes of unintentional weight loss.
- Inflammatory markers (ESR, CRP) and urinalysis help identify inflammatory conditions and infections.
- Fasting glucose is necessary to screen for diabetes, a common cause of unintentional weight loss. Additional important tests include:
- Hemoglobin A1C to screen for diabetes
- HIV testing
- Fecal occult blood test to check for gastrointestinal bleeding Depending on clinical suspicion, further testing may include:
- Cancer screening with tests like CA-125, CEA, PSA, or CT imaging
- Cortisol levels to evaluate for adrenal disorders
- Tests for malabsorption such as celiac antibodies These tests help identify common causes of unexplained weight loss, including cancer, thyroid disorders, diabetes, inflammatory conditions, and infections. Early comprehensive testing is crucial as unintentional weight loss, especially when exceeding 5% of body weight over 6-12 months, can indicate serious underlying conditions requiring prompt diagnosis and treatment, as noted in earlier guidelines 1.
From the Research
Laboratory Tests for Unintentional Weight Loss
The following laboratory tests are indicated for unintentional weight loss:
- Complete blood count 2, 3, 4, 5
- Basic metabolic panel 2, 3, 5
- Liver function tests 2, 6, 3, 4
- Thyroid function tests 2, 3, 5
- C-reactive protein level 2, 6, 3
- Erythrocyte sedimentation rate 2, 6, 3, 4
- Lactate dehydrogenase measurement 2, 3, 4
- Ferritin 2
- Protein electrophoresis 2
- Urinalysis 2, 3
- Glucose measurement 3
- Albumin 6, 4
- Haemoglobin 6
- Abdominal ultrasonography may also be considered 3, 4
- Chest radiography and fecal occult blood testing should be performed 2, 3
Additional Testing
Additional testing, such as computed tomography and gastrointestinal endoscopy, may be considered based on initial evaluation 4. Further imaging and invasive testing may be considered based on initial evaluation 2.
Diagnostic Approach
A clinical approach, including routine laboratory tests and abdominal ultrasonography, seems to be appropriate for detecting the majority of cases of cancer among patients with isolated involuntary weight loss 4.