Will a being on a ketogenic diet effect Blue Horizon blood test results?

[kendrewaddams]

Have had my Mum on a ketogenic diet for the past week and expecting to receive the test soon. I'm wondering whether a very low carb diet will effect the readings.

[Lotika]

The only thing which I can think of (I’m totally inexpert, mind) is that some patients feel low carb diets can negatively impact conversion of fT4 to fT3, which would only really apply if she was on levothyroxine, I imagine. So, if she were my mum - and on levothyroxine- I guess I’d be paying attention to her fT3 particularly. But otherwise, I can’t think of any further potential problem.

[kendrewaddams in reply to Lotika]

She is on levothyroxine. I guess just wait to see what the results say. Thanks!

[SlowDragon Administrator in reply to kendrewaddams]

What vitamin supplements is she currently taking?

Important to stop taking any supplements that contain biotin a week before ALL blood tests

Only test early Monday or Tuesday morning and post back straight away

All thyroid tests should be done as early as possible in morning before eating or drinking anything other than water and last dose levothyroxine 24 hours before test

Does she always get same brand brand of levothyroxine

Which brand?

[kendrewaddams in reply to SlowDragon]

Thanks for the reply

She's, in the past, taken lots of different ones, but at the moment it's - B12, D and sometimes Selenium.

She says she doesn't necessarily take the same brand of levothyroxine, but has been taking it since 2007 and has never noticed a marked improvement in her symptoms from any of them.

[SlowDragon Administrator in reply to kendrewaddams]

Which brand?

Teva brand upsets many, many people

[kendrewaddams in reply to SlowDragon]

It's Teva at the moment, but she's sometimes given different ones. What's the issue with Teva?

Thanks!

[SlowDragon Administrator in reply to kendrewaddams]

Many people find Levothyroxine brands are not interchangeable.

Many patients do NOT get on well with Teva brand of Levothyroxine. Teva contains mannitol as a filler, which seems to be possible cause of problems.

Teva is the only brand that makes 75mcg tablet. So if avoiding Teva for 75mcg dose ask for 25mcg to add to 50mcg or just extra 50mcg tablets to cut in half

But for some people (usually if lactose intolerant, Teva is by far the best option)

Teva, Aristo and Glenmark are the only lactose free tablets

Most easily available (and often most easily tolerated) are Mercury Pharma or Accord

Accord is also boxed as Almus via Boots, and Northstar 50mcg and 100mcg via Lloyds ....but beware 25mcg Northstar is Teva

List of different brands available in U.K.

thyroiduk.org/medications-f...

Teva poll

healthunlocked.com/thyroidu...

Once she finds a brand that suits you, best to make sure to only get that one at each prescription.

Watch out for brand change when dose is increased or at repeat prescription.

academic.oup.com/jcem/artic...

Physicians should: 1) alert patients that preparations may be switched at the pharmacy; 2) encourage patients to ask to remain on the same preparation at every pharmacy refill; and 3) make sure patients understand the need to have their TSH retested and the potential for dosing readjusted every time their LT4 preparation is switched (18).

Levothyroxine is an extremely fussy hormone and should always be taken on an empty stomach and then nothing apart from water for at least an hour after

Many people take Levothyroxine soon after waking, but it may be more convenient and perhaps more effective taken at bedtime

verywellhealth.com/best-tim...

No other medication or supplements at same as Levothyroxine, leave at least 2 hour gap.

Some like iron, calcium, magnesium, HRT, omeprazole or vitamin D should be four hours away

(Time gap doesn't apply to Vitamin D mouth spray)

If you normally take levothyroxine at bedtime/in night ...adjust timings as follows prior to blood test

If testing Monday morning, delay Saturday evening dose levothyroxine until Sunday morning. Delay Sunday evening dose levothyroxine until after blood test on Monday morning. Take Monday evening dose levothyroxine as per normal

[kendrewaddams in reply to SlowDragon]

Thanks very much. So with 100mcg NorthStar I'd be playing it safe?

[SlowDragon Administrator in reply to kendrewaddams]

100mcg and 50mcg Northstar are Accord

Accord don’t make 25mcg tablets

Mercury Pharma brand makes 25mcg, 50mcg and 100mcg tablets