What baseline laboratory tests should be obtained before initiating Ozempic (semaglutide) to assess glycemic control, renal and hepatic function, and contraindications?

Pre-Ozempic Laboratory Testing

Before initiating Ozempic (semaglutide), obtain baseline HbA1c, comprehensive metabolic panel (including creatinine/eGFR), and screen for absolute contraindications including personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia type 2 (MEN2). 1

Mandatory Baseline Laboratory Tests

Glycemic Control Assessment

• HbA1c to establish baseline glycemic control and determine treatment goals 1
• Fasting glucose for comprehensive metabolic assessment 1

Renal Function Evaluation

• Serum creatinine and eGFR are essential before initiation, though no dose adjustment is required for any degree of renal impairment 1, 2
• Baseline renal assessment allows monitoring for potential acute kidney injury from GI-related dehydration, which can occur with semaglutide 1
• Semaglutide causes an initial eGFR decline of 2-3 mL/min per 1.73 m² within the first 12-16 weeks, which then plateaus 2
• No dose adjustment is required across all stages of CKD, including eGFR <30 mL/min/1.73 m² 3, 4

Hepatic Function Assessment

• Liver function tests (AST, ALT, bilirubin) should be obtained at baseline 1
• No dose adjustment is required for hepatic impairment, but baseline values are necessary for future monitoring 1

Thyroid Screening

• TSH, T3, T4 should be measured before initiation 5
• While routine calcitonin measurement is not universally recommended by guidelines, the research evidence suggests it may be prudent given the thyroid C-cell tumor risk observed in rodent studies 5

Critical Contraindication Screening

Absolute Contraindications

• Personal or family history of medullary thyroid carcinoma – this is an FDA black box warning based on rodent studies 1, 4
• Multiple Endocrine Neoplasia syndrome type 2 (MEN2) 1, 4
• Pregnancy – verify pregnancy status in women of childbearing potential and ensure reliable contraception 1

Clinical History Assessment

• History of pancreatitis – screen for prior episodes or current risk factors, as pancreatitis is a relative caution 1, 3
• History of cholelithiasis or cholecystitis – avoid use in patients with active biliary disease 1
• History of diabetic retinopathy – particularly important for semaglutide, as the SUSTAIN-6 trial showed increased diabetic retinopathy complications 3
• Gastroparesis or severe GI motility disorders – relative caution due to delayed gastric emptying effects 1

Additional Assessments

Cardiovascular Risk Stratification

• Lipid panel (total cholesterol, LDL, HDL, triglycerides) to assess baseline cardiovascular risk 3
• Document history of cardiovascular disease, as semaglutide provides proven cardiovascular benefit in this population 4

Medication Review

• Review all concomitant medications, particularly:
  • Insulin or insulin secretagogues (sulfonylureas) – plan to reduce doses by 20-50% when initiating semaglutide to minimize hypoglycemia risk 3, 1
  • Oral contraceptives – advise switching to non-oral contraceptive method or adding barrier method during initiation and dose escalation 4

Ophthalmologic Evaluation

• Eye examination should be performed if not done within the last 12 months, particularly in patients with diabetes or history of uveitis 3
• This is especially important given the increased diabetic retinopathy complications observed with semaglutide 3

Common Pitfalls to Avoid

• Do not measure pancreatic lipase or amylase routinely at baseline unless clinically indicated, as research shows these are rarely checked in practice despite theoretical concerns 5
• Do not delay treatment waiting for calcitonin levels in patients without thyroid cancer risk factors, as this is not a guideline-recommended screening test 1
• Do not forget to assess disease history – research demonstrates that 98.6% of patients have at least one relevant disease history, yet only 1.8% receive adequate pretreatment screening 5
• Do not initiate in patients with HbA1c >10% or glucose ≥300 mg/dL with symptoms – insulin should be initiated first in these cases 4

Laboratory Tests NOT Routinely Required

• Calcitonin – not recommended by FDA or guidelines for routine screening, though some clinicians may consider it in high-risk patients 1, 5
• Pancreatic enzymes (lipase, amylase) – not required at baseline unless clinical suspicion of pancreatitis 5
• Urinary albumin-to-creatinine ratio (UACR) – while semaglutide improves albuminuria, baseline UACR is not mandatory for initiation but may be useful for monitoring renal protection 2