A pre-op appointment typically includes a physical exam, blood work, and a review of your medications and medical history. Depending on your age, health conditions, and the type of surgery you’re having, you may also get an EKG, chest X-ray, or urine test. The whole visit is designed to confirm you’re safe to go under anesthesia and to flag anything that could cause complications during or after the procedure.
Not everyone gets the same battery of tests. A healthy 30-year-old having a minor outpatient procedure will go through far less than a 70-year-old with diabetes scheduled for hip replacement. Here’s what to expect at each stage.
The Physical Exam
Your provider will listen to your heart and lungs, check your blood pressure, and assess your overall physical condition. One exam you might not expect: the airway assessment. You’ll be asked to sit upright, open your mouth wide, and stick out your tongue. The provider looks at how much of the back of your throat is visible, specifically the soft palate, uvula, and the arches around your tonsils. This is scored on a four-point scale. If you’re a Class I (everything clearly visible), intubation during anesthesia is straightforward. If you’re a Class IV (only the hard palate visible), the anesthesia team knows they may need special techniques to manage your airway.
The exam also covers your range of motion, skin condition near the surgical site, and any signs of infection. If you have a history of heart or lung problems, the provider will pay extra attention to those systems.
Standard Blood Work
The two most common blood panels are the complete blood count (CBC) and the basic metabolic panel (BMP).
A CBC measures your red blood cells, white blood cells, and platelets. The key number here is hemoglobin, the protein that carries oxygen in your blood. Normal hemoglobin runs 14 to 17 g/dL for men and 12 to 15 g/dL for women. If yours is low, that signals anemia, which can affect how well your body handles blood loss during surgery and how quickly you recover afterward.
A BMP checks your blood sugar, calcium, electrolytes, and kidney function. These values tell the surgical team whether your kidneys can handle the medications used during anesthesia and whether your electrolytes are balanced enough for your heart to function safely under stress. If you have diabetes, liver disease, or kidney problems, your provider may order a more comprehensive panel that includes liver enzymes and additional markers.
Clotting Tests
You might assume everyone gets their blood clotting checked before surgery, but that’s not always the case. Clotting tests measure how long it takes your blood to form a clot, and they’re commonly ordered for patients on blood thinners or those with liver disease. A large systematic review published in Blood found that these tests perform poorly as screening tools for predicting surgical bleeding in otherwise healthy people. Across 37 studies looking at major surgeries, 86.5% found no meaningful link between clotting test results and actual bleeding complications. The one exception was liver surgery, where there may be a real connection between clotting values and bleeding risk.
So if you’re not on anticoagulants and don’t have a known bleeding disorder, your surgeon may skip these entirely.
EKG and Chest X-Ray
An electrocardiogram (EKG) records your heart’s electrical activity and takes about 10 minutes. But it’s not automatic for every patient. Guidelines from the American Academy of Family Physicians recommend an EKG for patients undergoing high-risk surgery and for those having intermediate-risk surgery who have additional cardiac risk factors like a history of heart disease, heart failure, diabetes, kidney disease, or prior stroke. If you’re having a low-risk procedure, such as cataract surgery or a minor skin procedure, an EKG is not required.
Chest X-rays follow the same logic. Routine chest X-rays for healthy, asymptomatic patients are not recommended. You’ll only get one if you have new or unstable heart or lung symptoms, or if the results would actually change how your surgical team manages your care.
Specialty Screening Tests
Certain surgeries call for additional tests beyond the basics.
- MRSA nasal swab: If you’re having a joint replacement, you’ll likely get a nasal swab to check for staph bacteria. Staph infections are a serious risk with implant surgeries. If the swab comes back positive, you’ll be given a topical antibiotic to apply inside your nostrils three times a day for five days before surgery. This reduces the bacterial load by about 85%.
- Pregnancy test: Women of childbearing age are typically given a urine or blood pregnancy test before any procedure involving anesthesia, since many anesthetic agents pose risks to a developing fetus.
- Urinalysis: A urine test may be ordered if you’re having a urological procedure, joint replacement, or if your provider suspects a urinary tract infection that could spread during surgery.
Which Tests You Actually Need
There’s been a significant push in recent years to stop ordering blanket pre-op tests for everyone. The American Academy of Family Physicians specifically advises against routine preoperative testing before low-risk surgical procedures, noting that unnecessary tests create delays and add avoidable costs without improving outcomes. Preoperative assessment is still expected before all surgeries, but that assessment should be driven by your medical history and the complexity of the procedure, not by a one-size-fits-all checklist.
In practice, this means a healthy person having a straightforward outpatient procedure might only need a physical exam, a medication review, and basic blood work. Someone with multiple chronic conditions having major surgery will go through a much more thorough workup.
How Long Test Results Stay Valid
Pre-op test results are generally valid for six months, as long as nothing about your health has changed in the meantime. If you develop a new condition, start a new medication, or have a significant health event between your testing date and your surgery, expect to repeat some or all of the tests. Most surgical centers schedule the pre-op appointment one to four weeks before surgery to keep everything current.
Medication and Fasting Instructions
A major part of the pre-op appointment has nothing to do with tests. Your provider will go through every medication and supplement you take and tell you which ones to stop, which to continue, and when to take your last dose. Blood thinners, diabetes medications, and anti-inflammatory drugs commonly require adjustments in the days leading up to surgery. Herbal supplements like fish oil, garlic, and ginkgo can also affect bleeding and are usually stopped a week or two ahead of time.
You’ll also get fasting instructions. The American Society of Anesthesiologists sets minimum fasting periods for patients undergoing procedures with anesthesia or sedation:
- Clear liquids (water, black coffee, pulp-free juice, clear tea): stop 2 hours before
- Light meals (toast and clear liquids): stop 6 hours before
- Heavy meals (fried foods, fatty foods, meat): stop 8 or more hours before
- Breast milk (for infants): stop 4 hours before
- Infant formula or regular milk: stop 6 hours before
Clear liquids do not include alcohol. The reason for these rules is straightforward: food or liquid in your stomach during anesthesia can be inhaled into your lungs, causing a dangerous condition called aspiration pneumonia. Patients with diabetes face higher risk here because the condition can slow stomach emptying, so your anesthesia team will want to know your exact eating and drinking timeline.
What to Bring to the Appointment
Come prepared with a current list of all your medications, including doses. Bring your insurance card, a photo ID, and any recent test results from other providers that your surgical team might not have on file. If you use a CPAP machine for sleep apnea, mention it, as this directly affects your anesthesia plan. Write down your questions ahead of time, particularly about what to expect on the day of surgery, how long the recovery will be, and any restrictions on eating, drinking, or driving afterward.