PTH and secondary hyperparathyroidism: One had elevated PTH level (305.8 ng/L; reference range 18.5–88 ng/L), low calcium levels (1.74 mmol/L; reference range 2.18–2.60 mmol/L), and normal phosphate levels (1.26 mmol/L; reference range 0.84–1.45 mmol/L) in line with secondary hyperparathyroidism, while another two displayed PTH levels below the measurable level (<4.6 ng/L) in combination with low serum calcium (1.78 mmol/L and 1.91 mmol/) and high phosphate (2.17 mmol/L and 1.71 mmol/L) levels, suggesting primary hypoparathyroidism.