A recent consensus paper, released in collaboration by a number of leading medical bodies, re-confirms the vital role that PINP (Procollagen type I N-propeptide) and β-CTX-I (C-terminal telopeptide of type I collagen) must continue to play in osteoporosis treatment monitoring.

The paper also highlights for the first time the value of BALP (Bone Alkaline Phosphatase) and TRACP5b (Tartrate-resistant acid phosphatase isoform 5b) in assessing CKD-associated osteoporosis.

The paper, which was published on 28 March 2025, features input from the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO), the International Osteoporosis Foundation (IOF) and the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC).

Methodology

The recent paper was issued in succession of a 2011 paper1, released by the IOF and IFCC, which helped determine the clinical potential of PINP and β-CTX-I as bone turnover markers (BTMs) for monitoring osteoporosis. The field of BTMs has significantly advanced in the years since 2011, driving the need for new research into the efficacy of the BTMs proposed at that time.
Carrying out a literature review between 2011 and May 2024, the paper examines the impact of osteoporosis treatment on these BTMs. Studies of the accuracy of BTMs in the assessment of bone turnover in the setting of advanced chronic kidney disease (CKD) were also examined.

The role of PINP and β-CTX-I in monitoring anti-osteoporosis therapy

The article concludes that serum/plasma PINP and plasma β-CTX-I remain vital reference BTMs in osteoporosis and are considered useful for monitoring anti-osteoporosis therapy. Both represent a simple, low-risk, and convenient way to monitor effectiveness and adherence to anti-resorptive and anabolic therapies, potentially improving treatment adherence and effectiveness.
As part of our extensive Bone Turnover panel, IDS is proud to offer Intact PINP and β-CTX-I assays that are suitable for these purposes.

PINP and β-CTX-I assays

Our Intact PINP assay provides the only automated solution on the market for the quantitative determination of intact PINP in human serum or plasma. This assay detects only trimeric ‘intact PINP’ isoform, providing an accurate bone formation indicator even in renal-impaired patients.

Our Beta CrossLaps® (CTX-I) assay is intended for the quantitative determination of β-CTX-I in human serum or plasma.

Measuring the Intact PINP with the Beta CrossLaps® (CTX-I) assay from a single sample tube provides an effective tool in the monitoring of osteoporosis treatment and identifying patients at increased risk. Combining BTMs with the established IDS 25 VitD and IDS Intact PTH tests can aid management of osteoporosis and other metabolic bone diseases.

CKD-associated osteoporosis

Most previous observational studies of osteoporotic fractures and clinical therapeutic trials have excluded patients with chronic kidney disease (CKD) as subjects. Therefore, data on BTMs in these patients is limited. However, declining kidney function can disturb mineral metabolism, severely affecting bone remodelling, mineralisation and volume, ultimately resulting in condition known as CKD-associated osteoporosis.

The BTMs used for monitoring anti-osteoporosis therapy, total PINP and β-CTX-I are not suitable when CKD is present, as these accumulate with kidney disfunction, necessitating the need for alternative BTMs with CKD-associated osteoporosis.

The position paper identifies BALP and TRACPb5 as recommended reference markers for formation and resorption respectively in CKD-associated osteoporosis. This is because they are least affected by kidney function and therefore provide a more accurate and useful aid in assessing CKD patients and monitoring treatment.

BALP and TRACP5b assays

We are proud to offer the only automated BALP and TRACP5b assays available on the market, aiding with the monitoring of CKD-associated osteoporosis in conjunction with our sister company, EUROIMMUN.

Our Ostase® BAP assay is intended for the quantitative determination of BALP in human serum or plasma.

Our TRAcP 5b assay is the only automated assay intended for the quantitative determination of TRAcP 5b in human serum or plasma.

Combining the Ostase® BAP with the TRAcP 5b assay from a single sample tube provides accurate and reliable results, aiding clinicians to monitor osteoporosis treatment in the setting of impaired renal function.

Contact us

IDS is proud to offer a comprehensive portfolio of automated assays, which includes all bone turnover markers recommended for osteoporosis management and other bone diseases. This unique offer of fully automated assays is part of a wider endocrine category, which is suitable for use with a range of our instruments.

Browse our disease areas for a comprehensive list of the clinical areas we can support.

To find out more about specifying our assays for your clinical laboratory, contact us today.

References

1: Vasikaran S et al, International Osteoporosis Foundation and International Federation of Clinical Chemistry and Laboratory Medicine position on bone marker standards in osteoporosis. Clin Chem Lab Med. 2011 Aug;49(8):1271-1274. doi: 10.1515/CCLM.2011.602. PMID: 21605012