Nokuthula Nhlapo, Doreen Jacob, Siyabonga Khoza, Mpho R Maphayi
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引用次数: 0
Abstract
Background: Parathyroid hormone (PTH) measurement is key for diagnosing parathyroid disorders, and for management of chronic kidney disease. Available PTH assays include second (intact PTH) and third (PTH 1-84) generations. Data comparing interchangeable use are insufficient.
Objective: The objective of this study was to compare intact and 1-84 PTH assays to determine the difference in analytical performance and impact on clinical interpretation.
Methods: A method comparison was done on residual samples with PTH requests (06 April 2022 - 21 September 2022) from a tertiary hospital in South Africa. Parathyroid hormone was measured using both intact PTH and 1-84 PTH assays. Clinical performance was compared in the diagnosis of hypo- and hyperparathyroidism, and in pre-dialysis and dialysis chronic kidney disease patients.
Results: Among 481 samples, intact PTH had a higher median concentration than PTH 1-84 (9.85 pmol/L vs. 8.51 pmol/L, p < 0.0001), but the two showed good correlation (r = 0.994, p < 0.0001). Regression analysis revealed systematic (intercept = 0.887 pmol/L [95% confidence interval: 0.788 - 1.005]) and proportional differences (slope = 0.713 pmol/L, [95% confidence interval: 0.703 - 0.723]), with increased deviations at higher concentrations. The average bias was 18.5%, exceeding allowable limits. Among the 276 patients (170 women, 106 men, age range: 18-89 years) included in the clinical study, interpretation was unchanged.
Conclusion: A bias was observed between the PTH assays, indicating that they should not be used interchangeably. However, no changes in clinical interpretation were observed when one assay was used over the other.
What this study adds: The study confirms the recommendation by Kidney Disease: Improving Global Outcomes for the use of assay-specific upper limit of normal instead of generic cut-off in dialysis patients. This study further highlights the need for standardisation of PTH assays.
期刊介绍：
The African Journal of Laboratory Medicine, the official journal of ASLM, focuses on the role of the laboratory and its professionals in the clinical and public healthcare sectors,and is specifically based on an African frame of reference. Emphasis is on all aspects that promote and contribute to the laboratory medicine practices of Africa. This includes, amongst others: laboratories, biomedical scientists and clinicians, medical community, public health officials and policy makers, laboratory systems and policies (translation of laboratory knowledge, practices and technologies in clinical care), interfaces of laboratory with medical science, laboratory-based epidemiology, laboratory investigations, evidence-based effectiveness in real world (actual) settings.
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