Clinical utility and measurement of procalcitonin

Procalcitonin (PCT), regarded as a biomarker specific for bacterial infections, is used in a variety of clinical settings including primary care, emergency department and intensive care. PCT measurement aids in the diagnosis of sepsis and to guide and monitor antibiotic therapy. This article gives a brief overview of PCT and its use in guiding antibiotic therapy in various clinical settings, as well as its limitations. PCT performance in comparison with other biomarkers of infection in particular CRP is also reviewed. Owing to its greater availability, CRP has been widely used as a biomarker of infection and sepsis. PCT is often reported to be more superior to CRP, being more specific for sepsis and bacterial infection. PCT starts to rise earlier and returns to normal concentration more rapidly than CRP, allowing for an earlier diagnosis and better monitoring of disease progression

A multicenter study to evaluate harmonization of assays for N-terminal propeptide of type I procollagen (PINP): a report from the IFCC-IOF Joint Committee for Bone Metabolism

L

High-sensitivity cardiac troponin I improves cardiovascular risk prediction in older men: HIMS (The Health in Men Study)

Background: The Framingham Risk Score estimates the 10-year risk of cardiovascular events. However, it performs poorly in older adults. We evaluated the incremental benefit of adding high-sensitivity cardiac troponin I (hs-cTnI) to the Framingham Risk Score. Methods and Results: The HIMS (Health in Men Study) is a cohort study of community-dwelling men aged 70 to 89 years in Western Australia. Participants were identified from the electoral roll, with a subset undergoing plasma analysis. Hs-cTnI (Abbott Architect i2000SR) was measured in 1151 men without prior cardiovascular disease. The Western Australia Data Linkage System was used to identify incident cardiovascular events. After 10 years of follow-up, 252 men (22%) had a cardiovascular event (CVE+) and 899 did not (CVE–). The Framingham Risk Score placed 148 (59%) CVE+ and 415 (46%) CVE– in the high-risk category. In CVE– men, adding hs-cTnI affected the risk categories of 244 (27.2%) men, with 64.8% appropriately reclassified to a lower and 35.2% to a higher category, which decreased the number of high-risk men in the CVE– to 39%. In CVE+ men, adding hs-cTnI affected the risk categories of 61 (24.2%), with 50.8% appropriately reclassified to a higher and 49.2% to a lower category and 82.5% remaining above the 15% risk treatment threshold. The net reclassification index was 0.305 (P<0.001). Adding hs-cTnI increased the C-statistic modestly from 0.588 (95% CI, 0.552–0.624) to 0.624 (95% CI, 0.589–0.659) and improved model fit (likelihood ratio test, P<0.001). Conclusions: Adding hs-cTnI to the Framingham Risk Score provided incremental prognostic benefit in older men, especially aiding reclassification of individuals into a lower risk category

Practical Considerations for the Clinical Application of Bone Turnover Markers in Osteoporosis.

peer reviewedBone turnover markers (BTMs) are released during the bone remodelling cycle and are measurable in blood or urine, reflecting bone remodelling rate. They have been useful in elucidating the pharmacodynamics and effectiveness of osteoporosis medication in clinical trials and are increasingly used in routine clinical management of osteoporosis, especially for monitoring therapy, in addition to their use in other metabolic bone disease such as Paget's disease of bone and osteomalacia. Serum β isomerised C-terminal telopeptide of type I collagen and pro-collagen I N-terminal propeptide have been designated as reference BTMs for use in osteoporosis. In addition, bone-specific isoenzyme of alkaline phosphatase (B-ALP) secreted by osteoblasts and tartrate-resistant acid phosphatase 5b (TRACP-5b) secreted by osteoclasts are also found to be specific markers of bone formation and resorption, respectively. The concentrations of the latter enzymes in blood measured by immunoassay provide reliable measures of bone turnover even in the presence of renal failure. B-ALP is recommended for use in the assessment of renal bone disease of chronic kidney disease, and TRACP-5b shows promise as a marker of bone resorption in that condition. BTMs in blood do not suffer from biological variation to the same extent as the older BTMs that were measured in urine. Appropriate patient preparation and sample handling are important in obtaining accurate measures of BTMs for clinical use. Reference change values and treatment targets have been determined for the reference BTMs for their use in monitoring osteoporosis treatment. Further ongoing studies will enhance their clinical applications

Bone turnover markers: defining a therapeutic target

[Extract] Bone turnover markers (BTM) in widespread clinical use include urine NTX, plasma βCTX and plasma total procollagen type 1 amino terminal propeptide (P1NP). An important application of BTMs is in monitoring anti-osteoporosis therapy, and specifically, in indicating whether current therapy is likely to achieve optimal reduction of fracture risk. Of the 3 BTMs mentioned above, only urine NTX (as NTX/creatinine ratio) has an evidence-based threshold indicating optimum fracture risk reductio. However measurement of βCTX and P1NP is preferred owing to their smaller biological variation and greater response to treatment. We recently published provisional therapeutic thresholds for plasma βCTX assays that were equivalent to the urine NTX/creatinine ratio indicative of maximal fracture risk reduction for patients treated with risedronate