Laboratory Monitoring After Gastric Sleeve Surgery

First Year Monitoring Schedule

The British Obesity and Metabolic Surgery Society recommends comprehensive laboratory monitoring at 3, 6, and 12 months in the first year after gastric sleeve surgery, including complete blood count, ferritin, vitamin B12, folate, 25-hydroxyvitamin D, calcium, and comprehensive metabolic panel 1
Parathyroid hormone (PTH) should be checked if not done preoperatively to exclude primary hyperparathyroidism 1

The British Obesity and Metabolic Surgery Society recommends continuing monitoring at least annually for life after the first year, with a panel including complete blood count, ferritin, vitamin B12, folate, 25-hydroxyvitamin D, calcium, and comprehensive metabolic panel 1

Complete blood count (CBC) monitors for anemia, which occurs in up to 50% of post-gastric bypass patients and is also common after sleeve gastrectomy, according to the Obesity Reviews 1
Ferritin is essential for detecting iron deficiency before anemia develops, with iron deficiency being extremely common due to reduced gastric acid production and dietary intake 1
Vitamin B12 is critical because deficiency can cause irreversible neurological damage, affecting up to 61.8% of bariatric surgery patients 1
Folate deficiency develops from malabsorption and poor dietary intake 1
25-hydroxyvitamin D target levels are ≥75 nmol/L, with deficiency reported in up to 99% of patients with obesity preoperatively and persisting postoperatively 1
Calcium monitoring is necessary to prevent bone demineralization 1
Parathyroid hormone is more sensitive than calcium for detecting early disorders of calcium metabolism 1
Comprehensive metabolic panel, including renal function and liver function tests, is recommended 1

The British Obesity and Metabolic Surgery Society advises never prescribing high-dose folic acid without first checking vitamin B12, as folate can mask B12 deficiency while irreversible neurological damage progresses 1
Patients discharged from bariatric surgery service follow-up should undergo monitoring of nutritional status at least once a year as part of a shared care model of management 1