The chloride/phosphate ratio combined with alkaline phosphatase as a valuable predictive marker for primary hyperparathyroidism in Chinese individuals.

The chloride/phosphate ratio (Cl/PO4) has been suggested to have a role in primary hyperparathyroidism (PHPT), but the associations between Cl/PO4 combined with ALP level and PHPT has not been well-studied. Our aim was to investigate the predictive value of combination Cl/PO4 with ALP for PHPT. A cross-sectional retrospective analysis was conducted to examine 172 patients diagnosed with PHPT categorized into two groups: normocalcaemic primary hyperparathyroidism (NPHPT) group and hypercalcaemia PHPT group. We found that Cl/PO4 levels and ALP levels in the NPHPT and hypercalcaemia PHPT group were both significantly higher than normal controls. Cl/PO4 and ALP levels were an independent risk factor for PHPT. Cl/PO4 combined with ALP increased the receiver-operating characteristic curves (ROC-AUC) and the diagnostic value in NPHPT and hypercalcaemia PHPT group (0.913; 95% CI, 0.744-1.000 and 0.932; 95% CI, 0.897-0.966, respectively), specificity of 92.8% and sensitivity of 98%. In conclusion, combination Cl/PO4 with ALP might be a low-cost, simple, available predictive marker of PHPT in Chinese individuals, particularly Chinese remote region where the method used to measure PTH cannot be done. Moreover, due to serum calcium level in NPHPT, Cl/PO4 combined with ALP level measurement have great potential to predict significant occurrence of NPHPT.