Keto Test Strips: How Long Do They Stay Accurate?

Ketone test strips are thin paper strips that detect ketones in urine. They are a cheap and convenient way to test for ketosis, especially for people on the keto diet. The strips are available over the counter at pharmacies and supermarkets, as well as online. They typically expire within three to six months of opening. The process of using keto strips involves washing your hands, taking a urine sample in a small container, and immersing the absorptive end of the strip into the sample for a few seconds. After removing the strip from the sample, you wait for the amount of time outlined on the package for the strip to change colour. The colour of the strip is then compared to a colour chart on the packaging, with darker colours indicating higher ketone levels.

How to use keto urine test strips

Keto urine test strips are a cheap and convenient way to find out if your body is in ketosis. They are usually made from a type of paper that changes colour when it reacts with your urine. The strips have an absorptive pad on one end that contains a chemical reagent, usually nitroprusside, that changes colour in the presence of acids such as ketones in the urine. The darker the colour, the higher the concentration of ketones.

• Wash your hands.
• Collect a urine sample in a small, clean container. If you don't want to pee in a container, you can pass the end of the strip briefly through your urine stream.
• Dip the absorptive end of the strip into the sample for a few seconds. Alternatively, you can hold the strip in the stream of your urine until it's saturated.
• Wait for the amount of time outlined on the package for the strip to change colour. This is usually around 15 seconds.
• Compare the colour of the strip with the colour chart on the packaging. The colour corresponds to the concentration of ketones in your urine.
• Dispose of the urine and strip in an appropriate manner before washing your hands.

It is important to note that keto urine test strips are not always accurate, especially if you have been on the keto diet for a long time. This is because when your body makes more ketones than it can use, it gets rid of them through urine or breath. As a result, the strips may indicate that there are only trace amounts of ketones in your urine even though you are in ketosis. Therefore, it is recommended to use blood ketone meters or ketone breathalysers if you want a more accurate reading.

How accurate are keto urine test strips?

Keto urine test strips are a good tool to measure whether you are in ketosis, especially during the first few weeks of starting a keto diet. They are a cheap, convenient, and non-invasive way to test for ketosis. The strips are made from a type of paper that changes colour as it reacts with your urine. The darker the colour, the higher your ketone levels.

However, as your body gets deeper into ketosis, it adapts to using ketones for fuel and becomes more optimised in producing them, leaving less unused. This means that if you've been in a keto-adapted state for many months, a keto strip may indicate that your urine contains only trace amounts of ketones, if any. This can mislead people into thinking they're no longer in ketosis, which may not be the case.

For a more accurate reading, blood keto strips are a better option. However, they are more expensive and require you to prick your finger every time you measure your ketone levels.

Other factors that can affect urine ketone test results include:

• Adaptation: As your body maintains a ketogenic lifestyle, it becomes more effective at utilising ketones as fuel. This means that you might actually be at a deeper level of ketosis than what your test results show.
• Dehydration: One randomised controlled trial found a direct proportion between serum ketone concentration and the level of dehydration. Ensuring good hydration when testing for ketones can help produce more accurate and consistent results.
• Expired test strips: Check the expiration date of your urine test strips, as they typically expire within three to six months after opening. Store the bottle in a cool, dark place, away from direct sunlight to preserve their quality.

When is the best time to use keto urine test strips?

The best time to use keto urine test strips is early in the morning on an empty stomach, or in the evening, preferably at the same hour each time. This is because results are most reliable at these times. Testing at the same time each day will also allow for the best comparison of ketone levels over time.

It is also recommended that you test while fasted, in the morning, an hour or two after waking and before lunch or dinner (fasted for at least two hours).

If you are testing for ketosis, it is important to note that urine strips are not always accurate. They are most accurate when you are just entering ketosis, which is usually in the first week or two of a ketogenic diet. This is because, when your body is making more ketones than it can use, it gets rid of them through urine or breath. However, when ketones are fully metabolised, few, if any, will appear in the urine.

Therefore, if you are curious about your ketone levels, it is recommended that you test early in the morning or several hours after a meal.

How to interpret keto urine test strip results

Interpreting keto urine test strip results is simple. The strips have a light beige colour, which darkens with high levels of ketones. The deeper the colour, the more ketone bodies are detected in your urine.

• Negative (no ketones): You are not in ketosis at all
• Trace (0.5 mmol/L): This means light nutritional ketosis
• Small (1.5 mmol/L): This means light nutritional ketosis
• Moderate (4.0 mmol/L): Ketones increase further as a result of exercise or fasting
• Large (8.0 mmol/L): Usually a result of prolonged fasting, not sustainable in the long term
• Larger (16 mmol/L): Usually a result of prolonged fasting, not sustainable in the long term

Note: mmol/L stands for millimoles per litre, and it refers to the concentration of ketones in a specific amount of liquid — in this case, your urine.

The optimum level for ketosis falls between 0.5 and 2 mmol/L. However, higher ketones aren't necessarily better for everyone. While high ketone levels (5 mmol/L and above) can lead to more significant weight loss, this may eventually result in nutrient deprivation and a loss of muscle mass.

Other Factors That Affect Urine Ketone Test Results

In some cases, your ketone levels may decrease or increase despite your consistency with the keto diet. Here are a couple of reasons this occurs:

• Adaptation: As you maintain a ketogenic lifestyle, your body adapts, becoming more effective at utilising ketones as fuel. This means ketones are less likely to spill over into your urine. You might be at a deeper level of ketosis, but it doesn't show in your test results.
• Dehydration: One randomised controlled trial found a direct proportion between serum ketone concentration and the level of dehydration. The more dehydrated a subject was, the higher their ketone levels. Ensuring good hydration when testing for ketones helps produce more accurate and consistent results.
• Expired test strips: Check the expiration date of your urine test strips. Strips usually expire within three to six months after opening the sealed bottle container. Store the bottle in a cool, dark place, away from direct sunlight to preserve their quality.

How to Use Urine Test Strips

• Wash your hands.
• Pee in a small, clean container, then dip the test end of the strip into the urine sample. Alternatively, you can pass the end of the strip briefly through your urine stream.
• Wait for a few seconds (or as indicated on the test package) for the end of the strip to change colour.
• Compare the colour with the colour chart on the test package.
• Discard the urine testing strip. Then wash your hands.

Accuracy of Urine Test Strips

Testing your urine for ketones is generally considered less accurate than a blood ketone test. However, when done correctly, testing your urine for ketones at home can help you monitor a condition or know when it's time to call your healthcare provider for more care.

Where to buy keto urine test strips

Keto urine test strips are available at your local pharmacy and supermarket, as well as online. You can purchase them from familiar retailers such as Walmart and Perfect Keto. They are also available on online marketplaces such as Amazon and eBay.

These strips are a cheap and convenient way to test for ketosis. They are especially useful for those who are new to the keto diet and want an easy and affordable way to ensure they are headed towards ketosis.

The strips typically expire within three to six months after opening, so it is important to keep in mind how often you intend to use them. They are usually sold in containers with 50 to several hundred strips.

Frequently asked questions