Before gastric sleeve surgery can proceed, a series of medical assessments and tests are required. These are not formalities. They serve to establish your baseline health, identify any conditions that need to be addressed or managed before surgery, assess your surgical risk, and ensure that the surgical and anaesthetic team have the full picture they need to keep you safe.
Here is what the pre-operative assessment process typically involves and what we went through before our surgery at Weight Loss Riga in March 2024.
Blood tests
A comprehensive pre-operative blood panel is standard. This typically includes a full blood count to assess for anaemia or infection, metabolic panel covering kidney and liver function, blood glucose and HbA1c to assess diabetic status, thyroid function, a full vitamin and mineral profile including iron, B12, folate, vitamin D, calcium, and zinc, and lipid profile. This baseline is important because it identifies any deficiencies that need to be addressed before surgery, and it provides a reference point for post-operative monitoring.
James’s pre-operative bloods revealed his NAFLD-related liver markers, which the surgical team were aware of and factored into their planning. Knowing the full picture going in allows the team to prepare appropriately.
Cardiovascular assessment
An ECG is typically performed to assess heart rhythm and rule out cardiac abnormalities that could affect the safety of surgery or anaesthesia. For people with known cardiovascular disease or significant risk factors, more detailed cardiac assessment may be required. The goal is to ensure that the heart can safely handle the demands of general anaesthesia and surgery.
Respiratory assessment
Lung function and respiratory health are relevant to the safety of general anaesthesia, particularly in the context of surgery that involves the upper abdomen and diaphragm. For people with significant obesity-related respiratory conditions, additional respiratory assessment may be required before surgery can proceed safely.
Endoscopy
An upper GI endoscopy, where a thin flexible camera is passed through the mouth into the stomach, is recommended before gastric sleeve surgery to check the stomach and oesophagus for existing conditions. Hiatus hernia, H. pylori infection, gastritis, and other pathologies can all affect the surgical approach or post-operative management. H. pylori in particular needs to be treated before surgery if found, as the reduced acid environment after surgery makes eradication more difficult.
Psychological evaluation
A psychological or psychiatric assessment is a standard part of the pre-operative process at most reputable bariatric centres. This is not about gatekeeping surgery from people with mental health histories. It is about ensuring that the decision is being made from an informed and psychologically stable position, that expectations are realistic, and that appropriate support is in place for the psychological challenges of recovery.
The evaluation typically involves a structured interview covering mental health history, eating behaviour, motivations for surgery, understanding of what the surgery involves and its permanent nature, social support, and any active mental health conditions that may need additional support around the time of surgery.
Dietitian consultation
A consultation with a bariatric dietitian before surgery is important for establishing baseline dietary habits, explaining the post-operative dietary stages, and beginning the education around protein intake, supplementation, and the rules of post-surgical eating. This is also the point at which the pre-operative liver reduction diet is explained and commenced.
Anaesthetic review
An assessment by the anaesthetist before surgery allows any specific risks or concerns related to anaesthesia to be identified and planned for. James had a documented adverse reaction to a component of standard anaesthetic protocols that had been identified in advance. This allowed the anaesthetic team to plan a modified approach, and that preparation meant the reaction that did occur in theatre was managed safely and effectively. Disclosing your full medical history, including any previous anaesthetic reactions, is essential.
Sources
British Obesity and Metabolic Surgery Society (BOMSS): Pre-operative assessment guidelines. NICE: Obesity: identification, assessment and management. NHS: Weight loss surgery: what happens.
About this content
This blog is written by James and Kirsten, a couple from the UK who had gastric sleeve surgery together in March 2024.
We started this blog because we couldn't find any sources of content that details before surgery, the surgery and then life post surgery - so we decided to write one ourselves.
Everything on this site is based on our own experience and the research we have done along the way. It is not medical advice. Gastric sleeve surgery is a serious procedure and every patient's journey is different. Please always consult your own bariatric team or GP before making any decisions about your health or treatment.
Some posts on this site may contain featured or sponsored content, or affiliate links. Where this is the case, it will always be clearly stated at the top of the article. Our opinions are always our own.
Publish Date: 15 May 2026 | Last Reviewed: 7 June 2026 | Next Planned Review: 7 December 2027