From the Research
For patients presenting with chronic fatigue, initial screening blood tests should include complete blood count (CBC), comprehensive metabolic panel (CMP), thyroid-stimulating hormone (TSH), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and ferritin levels. These tests help identify common underlying causes of fatigue such as anemia, electrolyte imbalances, kidney or liver dysfunction, thyroid disorders, inflammation, and iron deficiency. Additional recommended tests include vitamin B12, vitamin D, fasting glucose, and hemoglobin A1c to rule out nutritional deficiencies and diabetes, as suggested by 1. In some cases, testing for infectious causes like Epstein-Barr virus, hepatitis, or HIV may be warranted based on clinical suspicion, as noted in 2. These tests provide a comprehensive baseline assessment to identify treatable medical conditions that could be causing fatigue symptoms. It's essential to consider the usefulness of CBC in assessing cardiovascular and metabolic diseases, as highlighted in 3, and the importance of interpreting laboratory findings in the context of a thorough clinical history and physical examination, as chronic fatigue can have multiple contributing factors, and normal test results don't exclude the possibility of chronic fatigue syndrome or other conditions requiring further evaluation, as discussed in 4 and 5. Key points to consider when evaluating patients with chronic fatigue include:
- A thorough clinical history and physical examination to identify potential underlying causes
- Laboratory tests to rule out common medical conditions, such as anemia, electrolyte imbalances, and thyroid disorders
- Consideration of lifestyle factors, such as sleep habits, diet, and physical activity level
- Potential referral to a specialist, such as a rheumatologist or endocrinologist, if an underlying condition is suspected.