From the Guidelines
For patients with weight gain, I recommend ordering a comprehensive panel of laboratory tests, including thyroid function tests, comprehensive metabolic panel, lipid panel, complete blood count, fasting insulin, and hemoglobin A1c, to identify potential underlying causes, as suggested by the most recent study 1. When evaluating weight gain, it is essential to consider various medical conditions that may contribute to this symptom. According to the study published in 2023 1, initial laboratory and diagnostic tests should investigate potential endocrine causes of obesity and examine the various components of metabolic syndrome, as well as kidney function and blood liver enzymes. Some key tests to consider include:
- Thyroid function tests, such as TSH, free T4, and free T3, to rule out hypothyroidism, which is a common cause of weight gain
- Comprehensive metabolic panel to assess liver and kidney function, glucose levels, and electrolytes
- Lipid panel, including total cholesterol, HDL, LDL, and triglycerides, to evaluate cardiovascular risk factors
- Complete blood count to identify anemia or other hematologic abnormalities
- Fasting insulin and hemoglobin A1c to screen for insulin resistance and diabetes
- For women of reproductive age, estrogen, progesterone, and testosterone levels should be checked, as hormonal imbalances can contribute to weight gain, such as polycystic ovary syndrome, as mentioned in the 2003 study 1 In cases where Cushing's syndrome is suspected, a 24-hour urinary cortisol test or overnight dexamethasone suppression test should be ordered. These tests will help identify medical conditions that may cause weight gain, allowing for appropriate treatment beyond lifestyle modifications, and ultimately improving morbidity, mortality, and quality of life outcomes.
From the Research
Weight Gain: Labs to Order
When evaluating a patient with weight gain, several laboratory tests can be ordered to assess the underlying cause of the weight gain.
- A complete blood count (CBC) and basic metabolic panel (BMP) can be used to rule out underlying medical conditions such as hypothyroidism 2.
- Thyroid function tests, including Thyroid-stimulating hormone (TSH) and free T4 (FT4), can be used to diagnose hypothyroidism, which is associated with weight gain 2.
- Lipid profiles, including total cholesterol (TC), high-density cholesterol (HDL-C), and triglycerides (TG), can be used to assess the patient's risk of cardiovascular disease and to monitor the effects of weight gain on lipid metabolism 2.
- Other laboratory tests, such as urinalysis and C-reactive protein measurement, may be ordered to rule out other underlying medical conditions, such as diverticulitis 3.
Obesity-Focused History and Physical Examination
In addition to laboratory tests, an obesity-focused history and physical examination are essential components of the evaluation process for weight gain 4, 5.
- The history should include questions about the patient's diet, physical activity level, and medical history, as well as any previous attempts at weight loss.
- The physical examination should include an assessment of the patient's body mass index (BMI), waist circumference, and blood pressure, as well as a thorough examination for any signs of underlying medical conditions.
Determining Risk Status
The National Heart, Lung, and Blood Institute Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults can be used to determine the patient's risk status based on their BMI and other health factors 5.