Chloride-phosphate ratio as a screening tool for primary hyperparathyroidism in calcium stone formers.
- Author:
Albert L CHU
;
Bien J MATAWARAN
;
David T BOLONG
;
Leilani B MERCADO-ASIS
- Publication Type:Journal Article, Original
- Keywords:
Primary HyperparathyroidismNephrolithiasisChloride-phosphate Ratio
- MeSH:
Hyperparathyroidism, Primary;
Nephrolithiasis
- From:
Philippine Journal of Internal Medicine
2012;50(1):1-4
- CountryPhilippines
-
Abstract:
Objective: To determine the accuracy of the chloride-phosphate ratio in the screening for primary hyperparathyroidism in calcium stone formers.Methods: Forty six subjects with nephrolithiasis were included in the study. Clinical and biochemical profiles of each patient were reviewed. Non-fasting blood was extracted for serum chloride and phosphate and compared with ionized calcium and intact parathyroid hormone (PTH) as the reference standard. The sensitivity, specificity, and likelihood ratios of the test against reference standard for the diagnosis of primary hyperparathyroidism (PHPT) were computed, as well as the receivers' operator curves.Results: Among the 46 subjects, 17 were recognized as positive biochemically for PHPT. Among calcium stone formers, the ratio of chloride and phosphate of greater than or equal to 33 has a sensitivity of 70.6% and specificity of 62.1% when compared with ionized calcium and PTH in the screening of PHPT in calcium stone formers. Using the ROC analysis, the best cut-off is at 32.4 while a cut-off of 27.98 has the best sensitivity of 94.12% (95% CI, 71.3-99.9).Conclusion: Among calcium stone formers, the chloride-phosphate ratio greater than or equal to 28 may be used for screening for PHPT with a sensitivity of 94%. It may be considered in the selection of patients for PTH assay or situations where PTH assay is not available.
