UK Reference Intervals for Parathyroid Hormone Using Abbott Methods.

Area of Science:

• Clinical Biochemistry
• Endocrinology
• Laboratory Medicine

Background:

• Hyperparathyroidism diagnosis relies on parathyroid hormone (PTH) levels alongside calcium, vitamin D, and renal function.
• Accurate patient classification necessitates appropriate population-specific reference intervals.
• Existing reference intervals may not accurately reflect local populations.

Purpose of the Study:

• To determine local population plasma PTH reference intervals at four UK sites.
• To compare these intervals with manufacturer-provided ranges.
• To assess the impact of local variations on hyperparathyroidism diagnosis.

Main Methods:

• Plasma PTH results were collected from four UK laboratories using the Abbott Architect i2000 method.
• Data included individuals with normal adjusted serum calcium, magnesium, vitamin D, and renal function.
• Outlier rejection was performed before deriving reference limits using parametric and non-parametric approaches.

Main Results:

• An overall UK reference interval of 3.0-13.7 pmol/L (non-parametric) was established, significantly higher than the manufacturer's 1.6-7.2 pmol/L range.
• Statistically significant differences in upper limits (11.5-15.8 pmol/L) were observed between sites.
• These variations suggest differences in local population characteristics.

Conclusions:

• Locally derived reference intervals for plasma PTH are beneficial for UK populations.
• Revised upper thresholds are needed for the Abbott PTH method to prevent misclassification of hyperparathyroidism.
• Site-specific reference intervals may improve diagnostic accuracy.