What labs should be checked before starting someone on a Glucagon-like peptide-1 (GLP-1) receptor agonist?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: July 1, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Before starting a patient on a GLP-1 receptor agonist, it is crucial to check renal function tests, including eGFR, as some medications require dose adjustments or are contraindicated in severe renal impairment, as noted in the study by Galindo et al 1. When initiating GLP-1 receptor agonist therapy, several laboratory tests should be considered to ensure safe and effective treatment.

  • Fasting blood glucose and hemoglobin A1C are essential for assessing glycemic control and determining the appropriateness of GLP-1 agonist therapy.
  • Renal function tests, including BUN, creatinine, and eGFR, are critical, as medications like exenatide and lixisenatide have specific dosing recommendations based on eGFR levels, and some are contraindicated in patients with severe renal impairment, as outlined in the study by Galindo et al 1.
  • Liver function tests, such as ALT and AST, should also be evaluated, as GLP-1 agonists can affect liver function, particularly in patients with pre-existing liver disease.
  • A pregnancy test is necessary for women of childbearing age, as the safety of GLP-1 agonists during pregnancy is not well established.
  • Thyroid function tests, including TSH, may be considered, given the potential association between some GLP-1 agonists and thyroid C-cell tumors in animal studies.
  • Baseline lipid panels and pancreatic enzymes, such as amylase and lipase, can help monitor potential changes in lipid profiles and the risk of pancreatitis associated with GLP-1 agonist therapy. These laboratory assessments are vital for ensuring the safe and effective use of GLP-1 receptor agonists, as they help establish baseline values, guide dose adjustments, and monitor potential adverse effects, as recommended by Galindo et al 1.

From the Research

Laboratory Tests Before Initiating GLP-1 Receptor Agonists

To ensure safe and effective use of GLP-1 receptor agonists, several laboratory tests should be considered before starting treatment. These tests help in assessing the patient's current health status, potential risks, and the suitability of GLP-1 receptor agonists for their condition.

  • Kidney Function Tests: Given the potential effects of GLP-1 receptor agonists on kidney function, especially in patients with chronic kidney disease (CKD) 2, assessing baseline kidney function through tests like estimated glomerular filtration rate (eGFR) or creatinine clearance is crucial.
  • Liver Function Tests: Although not directly mentioned in the provided studies, liver function tests might be relevant due to the metabolic effects of GLP-1 receptor agonists.
  • Blood Glucose and HbA1c: These are essential for diagnosing and monitoring diabetes, providing a baseline for the effectiveness of GLP-1 receptor agonist therapy 3, 4, 5.
  • Lipid Profiles: Since GLP-1 receptor agonists can affect weight and potentially lipid metabolism, baseline lipid profiles might be considered.
  • Pancreatic Enzymes: Due to the association concerns between GLP-1 receptor agonists and pancreatitis or pancreatic cancer, although recent meta-analyses suggest no significant association 6, monitoring pancreatic enzymes could be prudent in some cases.

Considerations for Specific Patient Groups

  • Patients with CKD: Close monitoring of kidney function is recommended, as GLP-1 receptor agonists may have varying effects on kidney outcomes in different stages of CKD 2.
  • Patients at Risk for Pancreatitis or Pancreatic Cancer: While the current evidence does not support a significant association with GLP-1 receptor agonists 6, vigilance and possibly baseline and periodic assessment of pancreatic enzymes might be considered on a case-by-case basis.

It's essential to tailor the choice and frequency of laboratory tests to the individual patient's health status, medical history, and specific GLP-1 receptor agonist prescribed, always considering the latest clinical guidelines and evidence-based practices.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.