However, they are significantly less than accurate!
Firstly, as you head towards “nutritional ketosis” two substances are produced that are found in the urine: acetoacetate and beta-hydroxybutyrate. It is the latter, beta-hydroxybutyrate that we are interested in, but, as Phinney and Volek say:
the strips that test for ketones in the urine detect the presence of acetoacetate, not beta-hydroxybutyrate
They go on:
In the kidney, this process of keto-adaptation is also complex. Over time, urine ketone excretion drops off … This decline in urine ketones happens over the same time-course that renal uric acid clearance returns to normal and thus may represent an adaptation in kidney organic acid metabolism in response to sustained carbohydrate restriction.
So we are not only measuring the wrong thing (acetoacetate vs beta-hydroxybutyrate), but over time acetoacetate excretion drops off (which is why so many people in ketogenic forums and Facebook groups keep asking why they are “no longer in ketosis” (as measured by the Ketostix) when they are being good and sticking to the diet. Phinney and Volek conclude:
These temporal changes in how the kidneys handle ketones make urine ketone testing a rather uncertain if not undependable way of monitoring dietary response/adherence. Testing serum for beta-hydroxybutyrate is much more accurate but requires drawing blood, and it is expensive because it is not a routine test that doctors normally order.
Well, there’s something they didn’t know when they wrote that: you can now do serum testing (testing the level of beta-hydroxybutyrate in your blood) at home with a simple meter that is similar to a blood glucose meter.
I have recently found a brand-new meter, an upgrade from the Precision Xtra, which is called the Freestyle Optium. I got mine for free! Further down this post, I will tell you how (although it may only be possible in the UK). So what follows between the rules is how it was until recently, and how it may still be outside the UK.
There are a couple of meters you can use, and they have been tested and compared by Jimmy Moore in his n=1 reports on his own progress with nutritional ketosis. One of the meters comes out badly in his review: you have to remember that these meters were not intended for the likes of us, who are trying to achieve nutritional ketosis, as defined by Phinney and Volek.
They are designed for Type 1 diabetics who are trying to avoid keto-acidosis (more of this further down this blog post). Which is why one of the meters just says “LO” for low measurements: that’s good enough (and good news) for someone who is Type 1.
Jimmy comes out in favour of Precision Xtra Meter, because it is capable of the levels of accuracy that we need.
However, especially if you live outside the USA (like, in the UK, as I do for a significant part of the year) the cost of the test strips for the Precision Xtra is a serious expense. In Amazon UK this pack is £66 plus £2 delivery for 10 (yes, that’s right, TEN!) strips.
That comes to £6.80 every time you do a test. I suspect you won’t test all that often! The meter from Amazon.co.uk is £25.48, including delivery.
If you are in the USA, the cheapest place I have found to get a Precision Xtra is MedExSupply.com, where, at the time of writing (August 10, 2013), it was $18.00. The best source of test strips is Universal Drugstore in Canada, where they come out at $2.00 a strip (plus $7.00 shipping). UDS need a prescription from your physician:here’s the e-mail they sent me describing what they need: Universal Drugstore e-mail.
However, that’s the bad news. Here’s the good news: I just got a brand-new, latest model meter for free, and 10 β-ketone test strips for £16.99. (Actually, I bought three boxes and paid extra for express delivery.) That comes out to $2.55 a test.
I had got so frustrated with my research that I Googled Abbott (the makers of the Precision Xtra) and discovered that they have a company in the UK, Abbott Diabetes Care. I called them and asked them about the Precision Xtra and they said that there’s a new model, the Freestyle Optium, and would I like them to send me one for free. I said yes, and two days later it arrived. It is a very cool little machine!
It measures both blood glucose and blood ketones (FreeStyle Optium β Ketone test strips for self-testing your blood ketones).
After quite a bit of Googling I found by far the cheapest source of these test strip on eBay: Freestyle Optium Beta B-Ketone Test Strips Pack Size 10.
If you want one too, call Abbott Diabetes Care in the UK on 0500 467 466 (it’s even a free phone number).
If you find information about this for other countries, let me know and I’ll add it here. And when my test strips arrive next Tuesday, I’ll let you know how I get on.
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