What Happens If You Don't Remove Nail Polish Before Surgery?

September 29, 2025 •

4 min read

During anesthesia, a pulse oximeter is used to monitor blood oxygen levels, and nail polish, particularly darker colors, can significantly interfere with the device's accuracy. This is the primary reason for the strict instruction to remove nail polish before surgery, as failing to do so can have serious safety implications.

Quick Summary

Wearing nail polish during surgery can interfere with the pulse oximeter, a vital device for monitoring blood oxygen saturation under anesthesia. This can produce inaccurate readings or mask a visible sign of low oxygen, compromising patient safety and potentially leading to a delayed or canceled procedure.

Key Points

Inaccurate Oxygen Readings: Nail polish, especially dark or gel colors, can interfere with the pulse oximeter, leading to inaccurate measurements of blood oxygen saturation.
Impaired Visual Cues: It can hide cyanosis, a bluish discoloration of the nail bed that signals dangerously low oxygen levels, which doctors and nurses monitor visually.
Risk of Delay: Arriving for your procedure with nail polish may cause your surgery to be delayed or, in some cases, canceled until the polish is removed.
Difficult Removal for Artificial Nails: Gel, acrylic, and other artificial nails can cause significant monitoring interference and are often required to be completely removed, at least from the fingers where a monitor will be placed.
Potential for Bacterial Growth: Old or chipped nail polish and artificial nails can harbor bacteria, which is a concern in a sterile surgical environment.
Alternative Monitoring Limitations: While monitoring sites like the earlobe or toe exist, the fingertip is the most accurate, and having polish on may necessitate using a less precise method.
Communication is Key: If you forget to remove polish, inform your medical team immediately upon arrival so they can address the issue and prevent delays.

While seemingly a small detail, the request to remove nail polish before a surgical procedure is a critical part of pre-operative preparation. The reasons are directly tied to your safety and the accuracy of medical monitoring during anesthesia. Failure to comply can compromise your care and, in some cases, cause delays or cancellations.

The Primary Concern: Compromised Oxygen Monitoring

The main reason hospitals require the removal of nail polish is to ensure accurate and reliable readings from a pulse oximeter. This small, non-invasive device is clipped onto a finger, sending a light beam through the tissue to measure blood oxygen saturation (SpO2). SpO2 is a vital sign monitored continuously by the anesthesia team during and immediately after your surgery.

How a Pulse Oximeter Works

A pulse oximeter measures the percentage of hemoglobin in your blood that is saturated with oxygen. It does this by passing red and infrared light through your finger. Oxygenated blood absorbs different amounts of light than deoxygenated blood, and the oximeter calculates the oxygen saturation based on these differences. This process relies on a clear, unobstructed path for the light.

The Effect of Nail Polish on the Device

Nail polish, and especially darker or opaque colors like black, blue, and brown, can block or absorb the light emitted by the pulse oximeter, preventing it from getting an accurate reading. Some studies even show that certain colors or types of gel polish can cause an overestimation of oxygen saturation, which could dangerously delay the detection of a problem. If a reading is unreliable, the medical team cannot be confident in the patient's oxygen levels, forcing them to find an alternative, and potentially less accurate, monitoring site.

Visual Assessment and Cyanosis

Before pulse oximetry became standard practice, medical professionals relied on visual observation of a patient's nail beds for signs of low oxygen levels, or cyanosis. Cyanosis is a bluish discoloration of the skin and nail beds that appears when oxygen levels drop. Nail polish completely masks this critical visual cue, which could otherwise be an important secondary indicator of a problem. While pulse oximeters are highly reliable, visual checks remain a foundational aspect of patient care.

Beyond Monitoring: Other Considerations

The Issue with Artificial and Gel Nails

Artificial nails like gels, shellac, and acrylics pose an even greater risk than standard nail polish. Not only do they interfere with pulse oximetry, but they can also make it impossible to place the sensor correctly. The thickness of the artificial nail can obstruct the light path, and if the nail is long, it may prevent the clip from fitting properly. Because removing these can be difficult and time-consuming, hospital protocols often require that they be removed from at least one finger on each hand prior to arrival.

Hygiene and Infection Risk

The operating room is a sterile environment, and there are additional hygiene concerns associated with nail polish and artificial nails. Chipped or old nail polish can harbor bacteria, and the surfaces of artificial nails can also contain germs that are hard to remove during a standard surgical scrub. While evidence linking patient nail polish to surgical site infection is not definitive, hospitals implement strict hygiene rules to minimize all potential sources of contamination. Long nails, which are often associated with polish, can also hold bacteria, further increasing the potential risk of infection.

Potential for Delays or Cancellation

If you arrive for your procedure with nail polish still on your fingers, the medical staff will likely require its removal before you can proceed. This can take up valuable time and potentially delay your surgery. In some facilities, particularly with hard-to-remove gel or acrylic nails, forgetting could lead to a reschedule or even cancellation of the procedure. Healthcare providers prioritize your safety above all else, and compromising on vital monitoring is not an option.

Comparison of Nail Conditions During Surgery


Feature	No Nail Polish	Regular Polish	Gel/Acrylic Nails
Pulse Oximetry	Accurate readings	Potential for inaccurate readings; interference increases with darker colors.	Significant interference; may not fit the device properly.
Visual Monitoring	Clear view of nail bed to detect cyanosis.	Masks visual cues of cyanosis.	Masks visual cues of cyanosis.
Hygiene Concerns	Minimal; nails can be thoroughly cleaned.	Chipped polish can harbor bacteria.	Increased risk of harboring bacteria; can't be easily sanitized.
Procedure Risk	Lowest; full monitoring capability.	Increased risk of delayed oxygen monitoring.	Increased risk due to significant monitoring interference.
Risk of Delay	None, regarding nails.	Possible delay for removal if forgotten.	Higher possibility of delay or cancellation for removal.

What to Do If You Forget

While you should plan to remove all polish before your surgery date, accidents happen. If you forget to remove your nail polish, inform a member of the surgical team as soon as you arrive. They will provide you with the necessary remover and may be able to remove it from one or two fingers—enough to place the monitor. For gel or acrylic nails, which require specialized tools, the process is more complicated, and staff may not be equipped to perform the removal. Communication is key to mitigating any risks or delays.

Conclusion: Patient Safety Comes First

The rule to remove nail polish before surgery is a simple yet crucial safety protocol designed to ensure the medical team can accurately monitor your oxygen levels. Nail polish interferes with the function of a pulse oximeter and obstructs visual signs of poor circulation, which are both essential aspects of patient care during anesthesia. While it may seem like a minor inconvenience, it is a non-negotiable step that protects your health and well-being during your procedure. Always follow pre-operative instructions carefully to ensure the safest possible outcome. For more detailed instructions on preparing for a procedure, consult a trusted medical source like the Cleveland Clinic's patient guide.

Frequently Asked Questions

Clear nail polish can still interfere with the pulse oximeter's ability to accurately read your oxygen saturation, though typically less than opaque colors. It is best to remove all nail polish to ensure the highest degree of monitoring accuracy.

Policies can vary by hospital and the type of surgery. While toenail polish generally does not interfere with monitoring if the probe is on a finger, it is always best to check with your surgical team. Some facilities require all polish, both finger and toe, to be removed.

Gel, shellac, and acrylic nails must be removed before surgery. Their thickness and opaqueness significantly interfere with pulse oximeter readings and can make it difficult for the device to attach properly. You should remove them from at least one finger on each hand before your arrival, as surgical staff may not be equipped to do it.

If you forget to remove your nail polish, inform your surgical team immediately upon arrival. They will likely have you remove it. This could cause a delay in your procedure. In the case of hard-to-remove artificial nails, it could potentially lead to a cancellation.

Yes, chipped nail polish and artificial nails can harbor bacteria that are difficult to eliminate with a surgical scrub. While evidence is inconclusive on whether this increases surgical site infection rates, hospitals enforce removal to maintain a sterile environment and minimize all potential risks.

The pulse oximeter provides continuous, real-time monitoring of your blood oxygen saturation during anesthesia. This allows the medical team to immediately detect and address any drop in oxygen levels, which is a critical safety measure during any surgical procedure.

While the reasons are universal for patient safety, specific hospital policies can differ. Some may allow clear polish, while others may require complete removal. It is always best to check the specific pre-operative instructions provided by your hospital or surgical center.