Bone turnover markers (CTX and P1NP): do you have a baseline?

Posted by mayblin @mayblin, Mar 27 11:05am

Currently i am on forteo therapy with a couple bone markers tests done. However, I didnt have ctx or p1np tested before the start of forteo as a baseline, regrettably.

It is known that the CTX value varies greatly among different individuals, with a very wide range. For post menopausal women, the range could be 34 - 1037 pg/ml; while for perimenopausal women 34-635 pg/ml. Different labs also have a slight different range values.

CTX, a bone resorption (breakdown) marker, is heavily influenced by a number of factors, such as food intake, circadian variation and exercise/life style, etc.

Bone remodeling is a dynamic and complex process. CTX itself may not fully reveal the whole picture. The bone building marker P1NP, is a lot less influenced by external factors. Taking both into consideration at the same time may shed more lights than looking at CTX or P1NP alone.

For those who had their CTX and P1NP tested before treatment with a bone drug, could you share the results if you don't mind? Thanks a lot!

Interested in more discussions like this? Go to the Osteoporosis & Bone Health Support Group.

bluebonnet242 | @bluebonnet242 | Apr 15 4:58pm

In reply to @mayblin "I’ll post the factors that will affect CTX and P1NP when I got time as I’m..." + (show)

Thanks!

gretch19 | @gretch19 | Apr 16 9:39am

In reply to @bluebonnet242 "@mayblin what is the best way to prepare for CTC and P1NP. I know I need..." + (show)

No collagen and Biotin for 2 days prior.
BTW, It is CTX

mayblin | @mayblin | Apr 16 1:48pm

In reply to @kristie2 "Hi, before I started Evenity my CTX was 933 and my P1NP was 77 and yes..." + (show)

your bone markers results after 4 months of Evenity is typical compared to the statistics of a clinical trial. Usually P1NP peaks at 2 weeks after 1st Evenity treatment and goes down towards the baseline after 4-6 months of treatment. So you might not ‘catch’ the peak/increase of P1NP reading. The CTX change is expected. So it’s more than likely that you are doing great with evenity!

Curious, are you going to be tested again for bone markers during the remainder of evenity therapy?

kristie2 | @kristie2 | Apr 16 6:02pm

In reply to @mayblin "your bone markers results after 4 months of Evenity is typical compared to the statistics of..." + (show)

I am planning on getting blood work again in a few weeks . I was very encouraged by my numbers .

nme1985 | @nme1985 | Apr 17 9:14am

In reply to @kristie2 "I am planning on getting blood work again in a few weeks . I was very..." + (show)

I am going for bloodwork next week. I plan to stop all vitamins and supplements four days before my blood work hopefully I will get a true reading. Good luck to all out there. Have a nice day.

mayblin | @mayblin | Apr 17 11:33am

In reply to @kristie2 "I am planning on getting blood work again in a few weeks . I was very..." + (show)

@kristie2 @nme1985 this sounds great! Keep us posted if you could!

mayblin | @mayblin | Apr 18 7:48am

In reply to @bluebonnet242 "@mayblin what is the best way to prepare for CTC and P1NP. I know I need..." + (show)

CTX and P1NP are the most popular bone turnover markers nowadays due to their sensitivity to change, or magnitude in change during a drug therapy and smaller variation (error bar for a data point) when compared to other bone markers such as NTx or bone ALP.

Among the two bone markers, CTX has a very wide reference range, reflecting large variation among different individuals as well within an individual. The influencing factors that are uncontrollable include age, gender, menopausal status, ethnicity, disease and drug, and fracture, etc. The following is a list of factors which can be controlled:
•circadian rhythms
•food intake
•menstrual
•seasonal
•exercise
•life style
Circadian rhythms and food intake plays a big part in daily ebb and flow of CTX. For example, CTX peaks at 01:30-04:30am, and bottoms at 11:00am-03:00pm. Food in the morning could decrease CTX reading as much as ~18%.

To summarize, in order to get a more accurate reading of CTX, it’s best to:
•fast in the morning;
•do an early morning 8-9am testing (within one hour of waking up if feasible) and be consistent in timing of blood drawing (set an appointment online!);
•stop collagen and biotin supplements 48-72hours before blood drawing;
•refrain from physical activity with high intensity for 24-48 hours. Daily walking should be fine
•stick with a same lab as different assays may be used at different labs

P1NP has very small fluctuations so get it done at the same time of CTX testing should give you a pretty reliable reading.

Bear in mind that there are so called “non-responders” whose bone marker testings do not show much changes (change greater than LSC -least significant change) during an antiresorptive or anabolic therapy. For instance, on average there are about 98% of responders to Alendronate/Fosamax at 12 weeks of treatment, 2% (2 out of 100 ppl on average) won’t have bone marker changes. This non-responder phenomenon applies to most of osteodrugs.

Hope other members also chime in with this topic to make the list complete so everyone could be better prepared for the tests and get most out of the labs.

Anyone has any take on VitD? Personally I kept taking my dose daily without modification in regard to bone marker testing.

bluebonnet242 | @bluebonnet242 | Apr 18 9:39am

In reply to @mayblin "CTX and P1NP are the most popular bone turnover markers nowadays due to their sensitivity to..." + (show)

@mayblin

P1NP has very small fluctuations so get it done at the same time of CTX testing should give you a pretty reliable reading.

Hope other members also chime in with this topic to make the list complete so everyone could be better prepared for the tests and get most out of the labs.

Anyone has any take on VitD? Personally I kept taking my dose daily without modification in regard to bone marker testing.

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Thank you so much for this detailed information!

mayblin | @mayblin | Apr 19 8:10am

In reply to @michaellavacot "Hi mayblin, I believe I have high baseline CTX from my hypercalciuria. I'm was peeing out..." + (show)

Hi @michaellavacot i am sorry to hear that evenity didn’t help building any significant bones for you. It seems your hypercalciuria, whatever the etiology might be, is robbing calcium from your bones, and your baseline CTX reflected that.

Hope you and your team of physicians will figure out the cause of hypercalciuria, whether it’s endocrinal origin, or renal origin or due to some other rarer disease state. Even if it turns out to be idiopathic, a proper control and treatment of hypercalciuria becomes a priority.

Best wishes!