Comparing Three Ketone Test Strips’ Accuracy at Home

I dipped three different ketone test sticks in my morning urine to compare their relative accuracy. One definitely didn’t work, but there are problems inherent in measuring ketosis with urinalysis strips. Knowing how they work helps you find the best keto strips at a good price.

What is “Keto”?

It usually means the “keto diet” or ketogenic diet, a low-carb, high-fat diet that causes the body to get into ketosis, and stay in ketosis. Ketosis is a state when the body is consuming fat and using it as an energy source.

The body normally prefers to use glucose as its energy source. Glucose is easy to eat, and some foods, like juices, are immediately absorbed and raise the blood glucose level. The pancreas releases insulin, a hormone which assists in “opening up” the cells to use the glucose as an energy source.

When someone eats a low-carbohydrate diet, the shortage of glucose causes the body to start using stored fat as an energy source. The liver goes into a state called ketogenesis, which means “creating ketones”. Ketogenesis produces two types of “ketone bodies”, or molecules, which are absorbed by cells (without insulin) and used as an energy source.

The two bodies are: Acetoacetate (AcAc), Beta-Hydroxybutyrate (β-hydroxybutyrate or BHB). The breakdown of AcAc produces Acetone, which is expelled in your breath, and has a flowery smell.

How Do You Test For Ketosis?

There are three technologies, ordered by declining accuracy: measuring acetone in the breath with a breathalyzer, measuring BHB in the blood with a blood test meter (similar to a blood glucose test), and measuring AcAc in the urine with a urinalysis test “stick”.

The reason why people use the AcAc urine test is because it’s the cheapest option, and also available over the counter at drug stores.

Unfortunately, it is also the least accurate, and I’ll describe why throughout this article. I’ll conclude with my comparative test of three different strips.

How Do AcAc Test Strips Work?

A test stick has a small pad impregnated with sodium nitroprusside. When soaked with urine, it reacts and darkens into a purple color if AcAc is present in the urine.

The test strip jar has a ketone levels chart showing the colors. The value is called “UA Ketones”, or urinalysis ketones. You may see that term “ua” because the fact it was measured from urine is important to doctors and nurses.

Always use the chart on the bottle – they aren’t the same across brands. Also, try to use an even, white colored light to view the results — any red or blue colors in the light will influence the way you see the results. (My lights are a bit red, and most people have that at home. Eventually, I’ll have to replace the bathroom lights with something that looks more cold, like a hospital’s lights.)

As stated above, in ketosis the body consumes AcAc for energy (and expels acetone). Therefore, the AcAc in urine is excess AcAc that’s being dumped out as waste.

What this means is that you can be in ketosis, and expel only small amounts of AcAc. So, the urine test is inherently less accurate than the acetone breath test.

You are supposed to measure your morning urine, because it’s the most concentrated, and also most likely to contain ketones, because you’ve been fasting (meaning you’re more likely to run out of glucose).

That points to another inherent inaccuracy of urine tests: drinking water dilutes the urine, and will cause a lower reading.

What about the BHB blood test? It also suffers from this limitation, because BHB is also consumed. However, BHB blood testing is more accurate because it’s measured before the body decides to dump the excess as waste. You’re measuring the liver’s output.

(Additionally, for diabetics, the BHB level rises more than the AcAc level when the body is getting into diabetic ketoacidosis (DKA), so Type 1 diabetics should use the blood test in addition to the urine test.)

Where Can I Buy Ketone Test Strips?

The most straightforward place to buy them is the drugstore, next to the pharmacy, in the shelves of items for diabetics. You should find AcAc ketone test sticks there. I got mine at CVS, but you can find them at all drugstores.

I also purchased two different sticks from two different vendors on Ebay. You can also find them online at the usual places: Amazon, GNC, and anywhere that sells nutritional supplements and diet aids for fitness enthusiasts.

On Ebay, you can buy them from a US vendor, who will ship them quickly, or from an Asian vendor, usually in China, who will ship them slowly (using ePacket). The China vendors are generally the least expensive.

You can also get urine test strips with multiple pads, to measure multiple aspects of urine chemistry. I recommend getting these, because they aren’t too expensive, and it’s more interesting to use. I got one from the same US vendor where I bought the ketone tests.

I got three strips from three different brands:

Cybow (DFI Co Ltd), Generic URS-1K, and TruePlus by Trividia (note the reddish cast to my bathroom lights)

There’s a brand called “ketostix”, and I think it’s by Bayer, but I didn’t get that.

Please note that all have expiration dates, and the TruePlus has a “date opened” space to write the date opened. These strips all react with air, water, and light, losing accuracy and efficacy with exposure.

In short, you cannot hoard these test sticks. They become useless.

How I Started Suspecting a Problem

My first batch of strips was the TruePlus, and they were reporting that I had AcAc, sometimes, quite a bit. My second batch was the Cybow, and it reported “trace” once or twice, but otherwise showed “neg”.

What seemed weird to me was that it was reporting nothing, but I was losing weight on a reduced carbohydrate diet, and also exercising a little more than in the past. The odds that I was producing and using ketone bodies was very high. Remember that the state of nutritional ketogenesis = converting fat to ketones, in the liver.

There are a few ways to lose weight: dehydrate and lose water, lose a limb, get liposuction and remove fat cells, lose muscle mass, and digest body fat the normal way your body uses it.

I was drinking a lot of water, and didn’t seem to be losing too much muscle mass, so… what was going on?

I cracked open a different pack of strips, and compared. The other strips reported “small”. Aha! Ketones!

How to Test Ketone Strips

I imagine a good testing fluid with a known quantity of AcAc in it is available, but I don’t know how to get it. I think the second best way is to put your body into ketogenesis.

How to Get Your Body Into Ketogenesis and Ketosis

If you’re obese like I am, the best way is to lose weight.

I also don’t think the keto diet is the best way: eating a high fat diet doesn’t sound healthy to me. Also, if you’re eating a lot of fat, of course you’re going to be in ketosis – the body is going to use that fat you ate instead of your body fat.

You also potentially lose the ability to verify that you’re losing weight. If you eat high fat, and maintain the same weight, how do you know that you’re in ketogenesis? You definitely don’t know.

If you are losing weight, and exercising to maintain muscle mass, you are probably in ketogenesis.

Exogenous Ketones

Some online promoters have a way to increase ketones in the bloodstream: eat raspberry ketone powder. Basically, it’s full of BHB ketones.

I don’t think these powders are a good idea, especially for diabetics. Ketones are an energy source for the body, but they are also amino acids.

As acids, they cause the blood to become acidic. The balance of acids and bases in the blood is critical to not dying. If you go too far in any direction, you’re going to get sick, and may die.

So, your body has multiple ways to deal with elevated or lowered acid levels. In some people, though, these regulatory mechanisms don’t seem to work so well.

Also, if you consume ketones, a source of energy, your body won’t consume its fat stores. You shouldn’t lose any weight.

How Did I Lose Weight?

I ate a low carb diet, to deal with my diabetes. Low carb, for me, meant between 80g and 150g of carbs a day, leaning more toward 100g than either end. I used Poundaweek to determine carb counts (and note, that is not accurate, either).

My fat consumption was somewhat high, and proteins were really high for a while, but I cut back. I cut calories, down to around 1400 to 1800 for most days, and lost weight. I also did a little exercise, mostly walking briskly and doing squats.

I wasn’t losing weight consistently, but I lost more often than gained. I went from a peak of 240 pounds down to 219, and the period in which I was measuring with the test sticks was around 225 to around 219.

During this time, I could also feel some of the more fatty, bulbous areas turn to softer flab. It was a sensuous experience ?

So I was “burning fat”.

How Did I Test the Strips? Comparatively

I measured the three strips against each other.

To do this, I gathered my morning urine into a small cup. (Normally, I urinate onto the strip, but for this test, I needed to measure the same batch of urine.)

The strips differed in how long each took to reach a final result. Cybow took 60 seconds. Generic took 40 seconds. Truvidia took 15 seconds. Note that this is another potential source of inaccuracy, because the pad continues to darken after the time period. You need to read it when you reach the designated time.

I suspect that the time required depends on the amount of sodium nitroprusside in the pad. Cybow reports 23mg. Truvidia says around 7% w/vol. I threw away the paper that came with the generic. In short, I cannot compare at this time.

Personally, I trust strips with shorter times more than those with longer times.

I timed the dipping so that they would all “mature” at the same time. Here are the photos of that:

The results were that the generic and TruePlus pads went to somewhere between “trace” and “small”. The Cybow went only to “negative”.

Cybow was not working.

What is the Best Ketone Test Strip?

I would argue that you cannot say one brand is “best” or “worst”. The test strips will vary based on how they’re stored, how you run the tests, and even manufacturing problems with batches.

It’s entirely possible that Cybow was a bad batch, and is otherwise a good brand. How would the Ebay vendor know? They may have purchased a big case, and trusted their wholesaler. They probably don’t have a neutral test that would be able to push the strips to display the different quantities of ketones.

They wouldn’t know the storage conditions at the wholesaler.

I noticed that the expiration date was 12/2020. That’s far in the future, but not as far as the others.

Likewise, while the generics seem to have good results, but it’s possible that the ones you order will be exposed to heat or cold, because they’ll spend a few weeks in transit.

(The ones I got had a foil seal, so air didn’t get into the bottle. That may have resulted in better results, but if the bottle itself is leaky, the strips can be damaged.)

The most reliable strips, I think, were the TruePlus strips, which, unfortunately, were the most expensive at around $10 per bottle.

They have a short time to test, and were sold at a drugstore with air conditioning. The drugstore handles tons of medications, and nearly all of them need to be stored in climate controlled warehouses, and probably also climate controlled trucks.

So, for myself, I’m going to continue to buy the cheaper strips from Ebay vendors, but test against the expensive strips from the drug store.

I’ll try to make the expensive strips last, and use the cheap strips more often. I test almost every urination at home, and am figuring out how to make a “road kit” to test when I’m away from home.


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