Routine lab work is essential after bariatric surgery. It helps your care team monitor nutrient levels, detect deficiencies early, and keep you feeling your best long term. Even if you feel fine, problems like low iron, B12, or vitamin D can develop slowly and without symptoms.
You will likely have lab work at three months, six months, and one year after surgery, then once or twice a year after that. Your surgeon or dietitian will give you a specific schedule based on your procedure and your individual needs.
Common labs include a complete blood count, metabolic panel, B12, iron studies, vitamin D, calcium, parathyroid hormone, folate, and thiamine. You may also need labs for zinc, copper, and fat-soluble vitamins like A, E, and K, depending on your surgery type.
The results help guide your supplement plan. If you are low in a specific vitamin or mineral, your team can adjust your dosage or recommend additional support. Keeping up with labs is one of the best ways to avoid complications and long-term health issues.
You can get your labs done through your primary care doctor, bariatric clinic, or an independent lab service. Make sure someone on your care team reviews the results with a focus on bariatric reference ranges, which can differ slightly from standard labs.
Some patients also use tracking apps, spreadsheets, or printed charts to log results over time. This helps you see trends and stay engaged in your care.
Lab work is not optional. It is a key part of long-term success and helps you catch problems before they become serious.
WLS and labs, not the four-legged kind
"Do you think I should keep taking my sublingual B12, Elizabeth?" Roxanne is 3 years post op from her gastric sleeve and is wondering if the expense of the meltable supplement is worth it.
"I am not sure, what does your latest B12 lab show?" I respond.
"Uh, I have not had labs done in, well, years," Roxanne admits.
And she is not alone. Scores and scores of WLS clients intend to keep up with the required post op labs but life gets in the way.
People, I am here to tell you, if it has been a long, long time since you have had your specific bariatric lab work done, run, do not walk, to your nearest phlebotomist.
Every few years, the Obesity Society, the American Society of Metabolic and Bariatric Surgery and the American Association of Clinical Endocrinologists update medical guidelines for bariatric surgery patients. They have a list of labs that need to be done at 3 and 6 months and those that need to be done annually. Yes, every single year, after surgery.
Why? Believe it or not, vitamin and mineral deficiencies increase over time, regardless of your WLS procedure.
I know many PCPs push back against ordering these regular labs, whether it is the cost to their practice, the patient or both. Many providers do not understand the necessity for the work-up.
What concerns me the most is that the damage from some vitamin and mineral deficiencies cannot be undone or corrected. The damage is permanent.
A psychiatrist speaker at a recent convention I attended talked about patients he has seen that were 6-10 years post op that were suffering from mental health issues, sometimes incapacitating problems. When he looked at their lab work, he was shocked to see that for some patients, vitamin and mineral deficiencies were the sole cause.
If your provider pushes back against these labs, I am happy to provide you with the link to the scientific paper citing which labs need to be done and when. You can share this with your provider and insurer.
Roxanne is off having her B12 checked as we speak. Armed with those results, we will be able to determine the most affordable and healthful path forward, specifically for her.
You deserve the same so make that appointment today. I thank you.