Lab Schedule by Procedure

Your Lab Schedule After Bariatric Surgery

What Gets Checked, When, and Why

Patient name: __________________________
Surgery date: __________________________
Procedure: _____________________________  

Why Labs Matter After Bariatric Surgery

Bariatric surgery changes how your body absorbs vitamins, minerals, and other nutrients. Some deficiencies develop gradually and may not cause noticeable symptoms until they are advanced.

Fatigue, hair loss, numbness, poor wound healing, vision problems, anemia, bone thinning, and muscle weakness can all be associated with nutritional deficiencies. Routine blood work helps identify these issues early, often before symptoms appear.

Laboratory monitoring is a lifelong part of bariatric care. Your surgeon or bariatric team may adjust the timing based on your procedure, symptoms, supplement use, and previous results.

Clinic Visit Schedule for All Procedures

A typical follow-up schedule includes visits and laboratory testing at:

• Month 1
• Month 3
• Month 6
• Month 12
• Annually thereafter for life

If a result is abnormal, your care team may repeat the test more frequently until the value is stable.

Sleeve Gastrectomy

Sleeve gastrectomy is generally less malabsorptive than gastric bypass or duodenal switch. However, nutrient deficiencies can still develop because food intake is reduced and changes in stomach acid may affect absorption.

At every visit

Typically at months 1, 3, 6, 12, and annually:

• Complete metabolic panel (CMP)
• Complete blood count with platelets (CBC)
• HbA1c if you have diabetes or prediabetes, until stable

Every 3–6 months during the first year, then annually

• Iron panel: serum iron, ferritin, and TIBC
• Vitamin B12
• Methylmalonic acid (MMA) if B12 is low or borderline
• Folate
• 25-hydroxyvitamin D
• Intact parathyroid hormone (PTH)
• Calcium, included in the CMP

Annually starting in year one

• Lipid panel
• TSH if you take thyroid medication or if clinically indicated
• Zinc if you have hair loss, poor wound healing, taste changes, or suspected protein-calorie malnutrition
• Albumin, included in the CMP

Additional testing when clinically indicated

• Vitamin A if symptoms or other fat-soluble vitamin deficiencies are present
• Copper and ceruloplasmin for unexplained anemia or neurological symptoms
• Thiamine, also called vitamin B1, if you have persistent vomiting, rapid weight loss, or neurological symptoms
• Selenium for unexplained anemia, cardiomyopathy, or persistent diarrhea
• Vitamins E and K when symptoms suggest deficiency

Bone density testing

A DXA scan may be recommended at baseline or within the first year, then every 1–2 years depending on your risk factors and results.

Roux-en-Y Gastric Bypass

Roux-en-Y gastric bypass bypasses portions of the small intestine, which can reduce absorption of iron, calcium, vitamin B12, folate, and other nutrients. Monitoring is therefore broader and may occur more frequently.

At every visit

Typically at months 1, 3, 6, 12, and annually:

• Complete metabolic panel (CMP)
• Complete blood count with platelets (CBC)
• HbA1c if you have diabetes or prediabetes, until stable

Every 3 months until stable, then every 6–12 months

• Iron panel: serum iron, ferritin, and TIBC
• Vitamin B12, with MMA if low or borderline
• Folate
• 25-hydroxyvitamin D
• Intact PTH
• Thiamine, or vitamin B1
• Copper and ceruloplasmin
• Zinc
• Selenium

“Until stable” generally means that results are within the desired range on two consecutive checks. If a value remains low or continues to fall, your care team may continue testing every three months regardless of how long it has been since surgery.

Every 6–12 months

• Vitamin A
• Lipid panel
• TSH if you take thyroid medication or if clinically indicated
• Albumin and prealbumin if protein malnutrition is suspected

Additional testing when clinically indicated

• Vitamins E and K or INR for bruising, bleeding, neurological symptoms, or vision-related symptoms
• Creatine kinase if rhabdomyolysis is suspected

Bone density testing

A DXA scan may be recommended at baseline or within the first year, then every 1–2 years based on your risk factors and results.

Duodenal Switch: BPD/DS and SADI-S

Duodenal switch procedures create greater malabsorption than sleeve gastrectomy or gastric bypass. This increases the risk of deficiencies involving fat-soluble vitamins, protein, iron, zinc, copper, and other nutrients.

SADI-S and BPD/DS have different surgical anatomy, but many programs use a similarly comprehensive monitoring schedule. Your surgeon will determine the appropriate plan for your procedure.

At every visit

Typically at months 1, 3, 6, and at least annually:

• Complete metabolic panel (CMP)
• Complete blood count with platelets (CBC)
• Albumin and prealbumin to assess protein status
• HbA1c if you have diabetes or prediabetes, until stable

Every 3 months during the first year, then at least annually

• Iron panel: serum iron, ferritin, and TIBC
• Vitamin B12, with MMA if low or borderline
• Folate
• 25-hydroxyvitamin D
• Intact PTH
• Vitamin A
• Zinc
• Copper and ceruloplasmin
• Thiamine, or vitamin B1
• Selenium

At least annually

• Vitamins E and K or INR
• Lipid panel
• TSH if you take thyroid medication or if clinically indicated

Additional testing when clinically indicated

• 24-hour urine calcium and oxalate if you have a history or symptoms of kidney stones
• Creatine kinase if rhabdomyolysis is suspected
• Additional testing for malabsorption or protein deficiency as recommended by your care team

Bone density testing

A DXA scan may be recommended at baseline or within the first year, then every 1–2 years. More frequent monitoring may be appropriate because of the increased risk of calcium and vitamin D malabsorption.

What Each Test Checks

CMP: Complete metabolic panel

Checks kidney function, liver function, blood sugar, electrolytes, calcium, and albumin.

CBC: Complete blood count

Measures red blood cells, white blood cells, and platelets. It can help identify anemia and other blood-related problems.

Iron panel

Includes serum iron, ferritin, and TIBC. It evaluates iron levels and iron stores. Iron deficiency may cause fatigue, weakness, shortness of breath, hair loss, and anemia.

Vitamin B12

Supports nerve function and red blood cell production. Deficiency may cause numbness, tingling, memory problems, balance problems, or anemia.

MMA: Methylmalonic acid

MMA can provide additional information when vitamin B12 is low or borderline. It may identify a functional B12 deficiency that is not clear from the B12 level alone.

Folate

Supports cell growth and red blood cell production. Folate is especially important for patients who may become pregnant.

25-hydroxyvitamin D

Measures vitamin D status, which affects bone health and calcium absorption.

PTH: Parathyroid hormone

PTH may rise when calcium or vitamin D is low. An elevated PTH can be an early warning sign of increased bone turnover.

Vitamin A

Supports vision, immune function, and skin health. Severe deficiency may cause night blindness or other vision problems.

Zinc

Supports immune function, wound healing, taste, and hair growth. Deficiency may cause hair loss, poor wound healing, or changes in taste.

Copper and ceruloplasmin

Copper supports nerve function and red blood cell production. Copper deficiency can resemble vitamin B12 deficiency and may cause serious neurological problems.

Because high-dose zinc can reduce copper absorption, your care team may monitor both nutrients.

Thiamine: Vitamin B1

Supports brain and nerve function. Deficiency can develop quickly with persistent vomiting, poor food intake, or rapid weight loss and requires prompt medical attention.

Selenium

Supports thyroid function and antioxidant defenses. Deficiency may contribute to unexplained anemia or heart muscle problems.

Vitamins E and K

Vitamin E supports nerves and red blood cells. Vitamin K is important for blood clotting. Both are fat-soluble vitamins and may be more difficult to absorb after malabsorptive procedures.

Albumin and prealbumin

These tests may help assess protein status, especially after a duodenal switch or when protein malnutrition is suspected.

HbA1c

Estimates average blood sugar over approximately three months. It is often monitored until diabetes is in remission or stable.

Lipid panel

Measures cholesterol and triglycerides. Medication doses may need adjustment as weight and metabolic health change.

TSH

Evaluates thyroid function. Thyroid medication absorption or dosing needs may change after surgery.

DXA scan

Measures bone mineral density and can identify bone thinning before a fracture occurs.

What Happens If a Lab Result Is Low?

If a result is below the desired range, your care team may:

1. Increase your supplement dose or change the form, such as using injections instead of oral medication.
2. Repeat the test in approximately 1–3 months.
3. Continue more frequent monitoring until the result improves and remains stable.

A low laboratory result is not a personal failure. It is information that allows your care team to adjust treatment before the deficiency causes serious complications.

Do not change supplement doses without speaking with your bariatric team.

Your Responsibilities

• Attend your laboratory appointments, even when you feel well.
• Continue monitoring for life.
• Take your prescribed vitamins and supplements consistently.
• Tell your care team if you have stopped or changed a supplement.
• Bring outside laboratory results to your bariatric team.
• Report unusual fatigue, hair loss, numbness, tingling, bruising, night-vision problems, muscle weakness, or bone pain.
• Ask whether you need to stop or adjust any supplements before blood work.

The Short Version

• Sleeve gastrectomy: Core labs are generally checked every 3–6 months during the first year, then annually. Additional nutrient testing may be added if symptoms or abnormal results occur.
• Roux-en-Y gastric bypass: Requires a broader panel. Testing is often performed every three months until results are stable, then every 6–12 months.
• Duodenal switch: Requires the most comprehensive monitoring because malabsorption is greater. Testing is typically performed every three months during the first year and at least annually thereafter.
• All procedures: CMP and CBC are commonly monitored during follow-up visits. DXA scanning may be performed at baseline or within the first year and repeated according to risk.
• All procedures: Lab monitoring and nutritional follow-up continue for life.

Deficiencies can develop silently. Regular laboratory testing helps identify and treat them before they cause lasting harm.

This guide is for education and does not replace your surgeon’s or bariatric team’s recommendations. Your testing schedule may vary according to your procedure, medical history, symptoms, medications, supplement use, and laboratory results.

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