Introduction

It’s been almost 8 months since I’ve picked up the Ketonix Sport directly from the Ketonix website, and in the interim it seems like the owner, Michel Lundell, has moved over to the Amazon platform. Currently there are two versions available on Amazon:

When I first purchased this the additional battery wasn’t available so I can’t really comment on how the battery works.

[UPDATE 5/31/2015:

At this point in time the Ketonix is no longer available on Amazon.

If you are interested in picking one up the 2015 Ketonix model is the only one available and it is available only on the Ketonix site for $149.]

What’s in the package?

The package is similar to what was contained with the Ketonix Standard version. It was shipped in a sturdy card board box and includes a blue velvet protective pouch (the Ketonix Standard came with a leather pouch). The Ketonix Sport itself looks exactly the same as the Ketonix Standard except for the brown color of the label and the words “Ketonix Sport.”

Like the standard version, the Ketonix Sport is the size of a large marker with a 3 foot USB cord attached to the base.

How to use it

The directions on the label read:

Connect to a USB port Wait until blue led is steady Blow gently into mouthpiece (10-15 sec) Watch the led color inside

Blue led – none/very small trace of ketones

Green led – small trace of ketones

Yellow led – moderate trace of ketones

Red blinking led – high trace of ketones

Wait until the blue led is steady before taking a new measurement. Do not use after meals or drinking alcohol. Keep out of reach for children. Do not use in water or vehicles.

For additional instructions you can refer to the Ketonix Support and Usage pages where he offers additional tidbits like always storing the Ketonix Sport in the pouch to protect the sensor and more detailed breathing instructions.

I noticed that on some days the Ketonix Sport would take 30 secs to calibrate and on other days it would take up to 2 minutes! I couldn’t figure out what variables affected this, but I frequently got impatient when it took 2 minutes to calibrate.

Brief Biochemistry Review

When entering ketosis, we are encouraging the body to utilize fat as fuel rather than carbohydrate (glycogen and glucose).

Fat is broken down into three main ketone bodies which the body then uses for energy

Beta-hydroxybutyrate (BHBA) – This is what is detected with blood ketone strips

Acetoacetate – This is what is detected with the urine ketone strips

Acetone – A break down product of acetoacetate which the body gets rid of via exhalation. Breath acetone is what the Ketonix Sport detects.

If you’d like a little more biochemistry and basics you can check out my Start Here page.

Difference between the Ketonix Sport and the Ketonix Standard

The primary difference is that the Ketonix Sport provides more detailed information for the exhaled breath ketones than the Ketonix Standard (here is my full review on the Ketonix Standard).

The Ketonix Standard displays 4 different LED colors:

Blue: 0 – 150 nmol/L

Green: 150 – 400 nmol/L (Small)

Yellow: 400 – 930 nmol/L (Moderate)

Red: > 930 nmol/L (Large)

The Ketonix Sport offers the same colors, however further breaks things down with differing amounts of flashes. The green LED can flash anywhere from 1 time to 10 times. The yellow and red LEDs also do the same and these flashes correspond to a more specific amount of breath ketones.

This is the graphic provided on the product page:

They seem to have changed the units from nmol/L to PPM from when I purchased the Ketonix Standard.

My interpretation of this scale is something like:

Blue ~ 0 – 5 ppm Green ~ 5 – 10 ppm (with range of 10 flashes)

Yellow ~ 10 – 20 ppm (with range of 10 flashes)

Red ~ 20 – 40 ppm (with range of 10 flashes)

So theoretically, a Yellow with 5 flashes would indicate around 15 ppm, and a Red with 5 flashes would indicate 30 ppm

On the other hand, in the videos Michel posts, he shows the green flashing twice and says it’s ~ 10 ppm, yellow flashing seven times being ~ 20 ppm, and red flashing three times being ~40 ppm… so I’m not entirely sure about this.

How I tested this

From October 27, 2014 to November 14, 2014, in the midst of my latest Carb Nite experiment (Week 1 and Week 2, unfortunately I never got around to posting the following weeks), I tested my fasting AM blood sugars and PM pre bed time blood sugars using the FreeStyle Lite Glucose Monitory System.

At the same time, I tested my blood ketones (both AM and PM) using the Precision Xtra Blood Ketone and Glucose System, and breathed into the Ketonix Sport.

If you want to see exactly what I ate during this time period, feel free to add me as a friend on myfitnesspal and browse through my food diary.

To make things a little easier to chart I assigned a linear numerical value to each potential combination of LED color and number of flashes.

As you can see on the chart to the right, I assigned a value of “0” to the blue color, and a number 1-10 for the color green, 11-20 for yellow, and 21-30 for red.

So if the Ketonix Sport showed a yellow light that flashed 4 times, this would correspond to the value ’14’ on my table.

If the Ketonix Sport showed a red light that flashed 7 times, this would correspond to ’27.’

My Hopes

I had high hopes for what the Ketonix Sport could provide in terms of data. In the best case scenario, I wanted there to be a clear linear relationship between blood ketones and breath acetone.

If my Precision Xtra showed 0.6 mmol/L, I wanted the Ketonix Sport to always show the same color and number of flashes.

If my Precision Xtra showed 2.5 mmol/L, I wanted the Ketonix Sport to show an even higher LED and number of flashes that was reproducible.

As we saw with my Ketonix Standard review this type of linear relationship did not exist. I hoped the Ketonix Sport would be different.

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RESULTS

Is there a linear relationship?

The answer is a big fat NO. I arranged the data in ascending order of blood ketone values. You can see that over the course of the experiment, my blood ketones ranged from 0.2 mmol/L to 1.5 mmol/L (a legitimate criticism of this is that I didn’t have higher blood ketone measurements like in the 2.0 or 3.0 mmol/L range).

For a blood ketone measurement of 0.4 mmol/L you can see that Ketonix Sport reported values of 6, 11, 21, and 22, which is a huge range.

The same could be said for all the other blood ketone measurements.

My hopes were dashed. No linear relationship existed whatsoever. For a given blood ketone measurement, it seemed that the Ketonix Sport would pull a random number out of a hat. I mean how could a 0.2 mmol/L blood ketone measurement correspond to a breath acetone of either a 6 OR 16?

So, I played with the data a bit…

I wondered if I was missing something. Maybe there was a correlation that I just wasn’t seeing. So I organized the data chronologically and made some charts…

AM Blood Ketone vs Ketonix Sport Breath Acetone

Do you see any clear relationship? Positive correlation? Negative correlation? Me neither. There might be something there… but nothing definitive.

PM Blood Ketone vs Ketonix Sport Breath Acetone

Hmm… again, maybe there’s something there? There’s a gap here where I forgot to take PM measurements one evening because I was waylaid by an inadvertent BBC Sherlock Holmes marathon.

Both AM and PM Blood Ketone vs Ketonix Sport Breath Acetone

Having so many data points made things look noisier on this chart. I thought I saw a pattern here but I still wasn’t convinced.

So I started wondering about trends. While the Ketonix Sport fails miserably in correlating with blood ketone measurements linearly, perhaps it correlated better in terms of general trends.

To further explore this, I took the same data set used here, with both AM and PM measurements, changed them to a scatter plot, and used a trend line with a 5 period simple moving average.

AM and PM Blood Ketone vs Ketonix Sport Breath Acetone 5 Period Simple Moving Average

Wow. The trend lines are almost identical! There is a pretty clear positive correlation between the two trends.

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Conclusion

After spending a good amount of time with the Ketonix Sport and parsing through all this data I feel like I can say for certain that it is a powerful tool if you’re interested in pursuing a ketogenic diet.

It’s not going to give you the moment by moment details that the current gold standard, blood ketones, can give you, but if you use it consistently, it will give you an accurate trend of where you’re going and where you’ve been.

It can tell you if you’re getting more ketotic or less ketotic, but it won’t give you an absolute number.

It’s important to remember that individual breath acetone measurements are essentially worthless, but the trend is where the money is.

If tracking your state of ketosis is important to you then I think this is the most cost effective tool for doing so. Since we already know how inaccurate urine dipsticks can be the longer you are ketoadapted I can’t encourage the use of these.

I recommend using the Precision Xtra Blood Ketone and Glucose System if:

Having accurate measurements is important to you (blood ketones are the gold standard)

You don’t mind constant finger pricks

You can afford the $3-5 per blood ketone strip

You want to know how certain foods or activities affect your blood ketones on a minute by minute or hour by hour basis

The Ketonix Sport is perfect for you if:

You’re ok with just knowing your general state of ketosis (by taking consistent measurements to get an accurate trend)

You want to save money (this will pay for itself after 30-40 measurements)

You value convenience (just blow into this thing for 15 secs)

You’re ok with the variable calibration times (30 secs to 2 minutes)

You understand it’s limitations.

If you want to pick one up you can get it at Amazon here:

UPDATE:

Over at the KetoGains Subreddit where I shared this post, user leclisse kindly created a scatterplot comparing blood BHOB and the Ketonix readings:

Leclisse also did some statistical analysis and calculated rho = 0.316 and p = .03, which doesn’t really mean anything to me since I completely suck at statistics (anything beyond mean, median, and mode is beyond me)… so I’ll just cut and post leclisse’s entire comment:

There’s a positive correlation after statistical analysis for your data: rho = .316, p = .03 one-tailed. EDIT: just to make sure no one takes this incorrectly, this sort of analysis isn’t exactly appropriate; we can’t conclude that this correlation exists in anyone else, just that in you the readings are correlated. Details—SPSS 21. Your data were non-normal and ketonix may not be scalar, so I used a nonparametric spearman’s correlation; one-tailed significance testing because we expect (and previous studies show) a positive correlation.