From the Guidelines
Annual laboratory tests for bariatric surgery patients should include a comprehensive metabolic panel, complete blood count, lipid panel, hemoglobin A1C, vitamin B12, folate, iron studies, vitamin D, parathyroid hormone, and fat-soluble vitamins. These tests are essential because bariatric procedures alter the digestive anatomy, potentially leading to nutrient malabsorption and metabolic changes, as recommended by the British Obesity and Metabolic Surgery Society guidelines 1. The comprehensive metabolic panel monitors liver and kidney function, while the complete blood count screens for anemia, which is common due to reduced iron and B12 absorption. Vitamin and mineral levels require monitoring because the altered digestive tract may impair absorption, particularly of fat-soluble vitamins, B12, iron, and calcium. Some key points to consider when monitoring bariatric surgery patients include:
- Checking full blood count including haemoglobin, ferritin, folate and vitamin B12 levels, as well as serum 25-hydroxyvitamin D levels, and serum calcium and parathyroid hormone levels 1
- Considering checking serum vitamin A levels in individuals going forward for malabsorptive procedures such as BPD/DS or where vitamin A deficiency may be suspected 1
- Treating and correcting nutritional deficiencies preoperatively as individuals have an increased risk of deficiencies postoperatively 1 Patients who have had malabsorptive procedures like gastric bypass or duodenal switch need more vigilant monitoring than those with restrictive procedures like sleeve gastrectomy. Additional tests may be needed based on individual risk factors, symptoms, or medication use. Regular laboratory monitoring helps identify deficiencies early, allowing for prompt supplementation adjustments to prevent complications like anemia, osteoporosis, or neurological issues, and is supported by studies such as those published in Advances in Nutrition 1 and Obesity Reviews 1.
From the Research
Bariatric Annual Labs
To check for various health conditions after bariatric surgery, the following annual labs are recommended:
- Complete Blood Count (CBC) to assess cardiovascular and metabolic diseases, including:
- White blood cell (WBC) count
- Neutrophil-to-lymphocyte ratio (NLR)
- Hemoglobin (Hb) level
- Mean corpuscular volume (MCV)
- Red cell distribution width (RDW)
- Platelet count
- Mean platelet volume (MPV)
- Platelet-to-lymphocyte ratio (PLR) 2
- Other tests may be recommended based on individual patient needs and medical history
Limitations of Current Evidence
There is limited direct evidence on the specific annual labs required for bariatric patients. However, studies suggest that CBC components can be useful markers to predict cardiovascular disease and metabolic diseases 2. Other studies are not directly relevant to this question, focusing on topics such as enzyme isolation and cancer therapy 3, 4