Which laboratory test combination is appropriate to monitor vitamin D status, PTH, and B12 after bariatric surgery?

Which laboratory test combination is appropriate to monitor vitamin D status, PTH, and B12 after bariatric surgery?

• A. Niacin, vitamin B12, and zinc
• B. Calcium, magnesium, and vitamin A
• C. 25-Hydroxy Vitamin D, Intact PTH, and Vitamin B12
• D. Intact PTH, 1,25-dihydroxy Vitamin D, and thiamin

Answer: (C)

The main idea here is to monitor nutrients most affected after bariatric surgery that influence bone health and neurological function: vitamin D status, calcium metabolism, and vitamin B12. Using 25-hydroxy vitamin D gives a reliable picture of vitamin D stores, which guides supplementation to prevent deficiency and secondary hyperparathyroidism. Intact PTH is the best lab to assess how the parathyroid glands and calcium homeostasis are responding to that vitamin D status; rising PTH indicates that calcium/vitamin D sufficiency is not adequate and signals potential bone loss risk. Vitamin B12 status is essential to check because malabsorption from bariatric procedures can lead to deficiency, affecting neurological and hematologic health. 1,25-dihydroxy vitamin D isn’t ideal for routine monitoring because it reflects the active hormone level and can be normal or misleading even when stores are low. Thiamin (B1) is important in acute or severe malnutrition, but it doesn’t address vitamin D or PTH status. Other nutrients like calcium, magnesium, or vitamin A don’t directly track vitamin D stores and calcium regulation together like this panel does.

The main idea here is to monitor nutrients most affected after bariatric surgery that influence bone health and neurological function: vitamin D status, calcium metabolism, and vitamin B12. Using 25-hydroxy vitamin D gives a reliable picture of vitamin D stores, which guides supplementation to prevent deficiency and secondary hyperparathyroidism. Intact PTH is the best lab to assess how the parathyroid glands and calcium homeostasis are responding to that vitamin D status; rising PTH indicates that calcium/vitamin D sufficiency is not adequate and signals potential bone loss risk. Vitamin B12 status is essential to check because malabsorption from bariatric procedures can lead to deficiency, affecting neurological and hematologic health.

1,25-dihydroxy vitamin D isn’t ideal for routine monitoring because it reflects the active hormone level and can be normal or misleading even when stores are low. Thiamin (B1) is important in acute or severe malnutrition, but it doesn’t address vitamin D or PTH status. Other nutrients like calcium, magnesium, or vitamin A don’t directly track vitamin D stores and calcium regulation together like this panel does.