From the Guidelines
A comprehensive weight gain workup should include a basic laboratory evaluation of a comprehensive metabolic panel, fasting lipid profile, and thyroid function tests, as recommended by the 2017 white paper by the AGA 1. This evaluation is crucial in identifying underlying medical conditions that may contribute to weight gain, such as hypothyroidism, diabetes, insulin resistance, or hormonal imbalances.
- The comprehensive metabolic panel assesses liver and kidney function, while also checking electrolytes that might indicate metabolic disturbances.
- The fasting lipid profile is important to evaluate cardiovascular risk associated with weight gain.
- Thyroid function tests, including TSH and free T4, help identify hypothyroidism, a common cause of weight gain. Additional tests to consider are:
- Insulin levels to assess insulin resistance
- Cortisol levels (morning) to evaluate for Cushing's syndrome
- Sex hormone levels (testosterone in men, estradiol and FSH in women) to identify hormonal imbalances These tests should be interpreted in the context of a thorough medical history, physical examination, and assessment of lifestyle factors, including diet, physical activity, sleep patterns, and medication use, as these elements are equally important in understanding the cause of weight gain 1. It is also important to note that certain medications, such as those used to treat diabetes, can contribute to weight gain, and alternative medications that are weight-neutral or promote weight loss should be considered 1.
From the Research
Weight Gain Workup Labs
The following labs are recommended for a weight gain workup:
- Comprehensive metabolic panel (CMP) to evaluate glucose, electrolyte, and liver function levels 2
- Thyroid function tests, including thyroid-stimulating hormone (TSH), free thyroxine, and free triiodothyronine, to rule out hypothyroidism as a cause of weight gain 3
- Fasting insulin and glucose levels to assess insulin resistance and glucose metabolism 4
- Lipid profile to evaluate cholesterol and triglyceride levels 5
- Inflammatory markers, such as C-reactive protein (CRP), to assess inflammation and potential metabolic syndrome 4
- Additional tests may be ordered based on individual patient factors, such as liver function tests or glucose tolerance tests 6
Key Considerations
When interpreting lab results, consider the following:
- Clinical context, including patient medical history and current symptoms 3
- Potential assay interferences or effects of concurrent medications 3
- Normal thyroid physiology and potential pitfalls in thyroid function test interpretation 3
- Individual patient factors, such as baseline weight and dietary habits, that may influence weight gain 6