Will Weed Show Up on a Hospital Drug Test?

If you’ve got an upcoming surgery and recently used cannabis, nicotine, or prescription meds, you’re not alone in wondering what the hospital might test for—and whether it could affect your procedure. With marijuana now legal in many states, this concern is increasingly common.

First, it’s important to understand that pre-operative drug screening is not the same as a workplace drug test. Hospitals and surgical teams aren’t usually looking to penalize or disqualify patients—they’re focused on ensuring your safety during and after surgery.

Whether you're going in for an elective procedure or facing an emergency surgery, pre-op protocols will vary. In most cases, any tests or screenings are designed to assess how your body will respond to anesthesia and recovery—not to enforce lifestyle choices. Still, being honest and informed can make a big difference in your outcome.

Let’s break down exactly what to expect during pre-surgical testing and whether cannabis, nicotine, or other substances are likely to show up—or matter at all. For a deeper dive into detection windows, visit our guide on how long drugs stay in your system.

What Happens During Pre-Surgery Testing?

Before any surgical procedure, hospitals typically require a pre-operative screening process. This helps your medical team assess your overall health and minimize risks associated with anesthesia and surgery.

The most common tests include:

• Blood work: A complete blood count (CBC) and metabolic panel are standard. These help evaluate organ function, blood sugar levels, electrolytes, and more.
• Urinalysis: Urine tests are usually performed to check for infections or kidney function—not specifically for drugs. Routine pre-op urine screens typically don’t include THC or nicotine unless there’s a medical reason.
• Imaging & cardiac testing: Depending on your age, medical history, or the procedure itself, an EKG (electrocardiogram) or chest x-ray might also be ordered to evaluate heart and lung function.

It’s important to remember that these tests are not designed to pass judgment. Hospitals are focused on safety—especially how your body might react under anesthesia or during recovery. If any substances in your system could pose a risk, the goal is to adjust the care plan, not cancel the surgery outright.

If you're curious about how long cannabis or nicotine might stay in your body, check out our breakdowns on THC detection timelines and whether nicotine shows up in a drug test.

Do Hospitals Drug Test Before Surgery?

Drug testing before surgery is not a standard practice for most hospitals—especially for cannabis or nicotine. Instead, pre-operative screening typically focuses on lab work, physical health, and any known medical risks that could interfere with anesthesia or recovery.

That said, drug testing can occur under certain conditions. If a patient has a documented history of substance use, is on medications that could interact with anesthesia, or displays symptoms that raise red flags, the surgical team may order a toxicology screen. This is especially true for high-risk procedures where safety is paramount.

For elective surgeries—like cosmetic procedures or non-urgent orthopedic operations—patients who do not disclose recent drug or tobacco use might face delays or cancellations if issues arise during screening or consultation. Honesty with your medical team is critical for both safety and scheduling.

Importantly, substances like THC and nicotine are rarely automatic disqualifiers for surgery. However, they can impact your treatment plan, particularly if your cannabis use affects heart rate, lung function, or interacts with sedatives. Smoking of any kind (including vapes and pouches) may also slow healing and increase post-op complications.

Still wondering what could show up? Our guide on drug detection times by test type can help clarify the bigger picture.

Can Weed or Nicotine Cause Surgery Complications?

Yes—both cannabis and nicotine can affect how your body responds to surgery, especially under anesthesia. While these substances may not trigger a formal drug test, they can complicate your procedure if not disclosed to your medical team.

THC (tetrahydrocannabinol), the active compound in weed, can influence heart rate, blood pressure, and respiratory function. These are all critical factors when undergoing sedation or anesthesia. If you're a regular cannabis user, your tolerance may also affect how anesthetics work—potentially requiring adjusted dosages or additional monitoring during surgery.

Nicotine—whether through smoking, vaping, or using pouches—poses its own set of risks. It can constrict blood vessels, reduce oxygen delivery, and slow wound healing, all of which may increase the chances of infection or prolonged recovery. Even smokeless options like nicotine pouches aren’t exempt, as they still affect your circulatory system.

For more on how nicotine could appear on lab work or influence outcomes, visit our guide on nicotine and drug testing.

This is why full disclosure is essential. Anesthesiologists and surgeons aren’t there to scold you—they’re there to protect you. Knowing about your cannabis or nicotine use helps them plan a safer and more effective surgical strategy, minimizing complications before, during, and after the operation.

What to Do If You’re Concerned

If you’re nervous about what might show up in your pre-op testing—or how certain habits could affect your surgery—there are a few things you can do to prepare your body for the safest outcome possible.

Start with the basics: drink plenty of water, eat a clean and balanced diet, and get adequate rest in the days leading up to your procedure. These practices support liver and kidney function, which in turn helps your body naturally process and eliminate substances over time.

Some patients also choose to use detox drinks as part of their general wellness routine. While these products are not guaranteed to “beat” a test—and should never replace medical disclosure—they can be a helpful tool for those looking to support their body’s natural cleansing processes.

Need help understanding what your timeline looks like? See our full guides on how long weed stays in your system and drug detection timelines.

FAQs: Weed, Nicotine, and Surgery Drug Tests