<abstract xmlns="http://www.w3.org/1999/xhtml">

<bold>Objective:</bold> to describe the results from intravenous calcium loads in patients with suspected PHPT.
<bold>Methods:</bold> This was a retrospective cross-sectional study with inpatients’ data review. Baseline serum calcium, phosphates, magnesium, creatinine, alkaline phosphatase, beta-crosslinks were recorded. The calcium loading had been performed after an overnight fasting. Calcium gluconate 0.25 mmol/kg body weight (10 mg/kg) dissolved in 0.9% Sodium Chloride was infused intravenously for 3 hours. Blood samples for total serum calcium, phosphates and iPTH were drawn before and up to 60 minutes after the calcium load. The intact parathyroid hormone (iPTH) and 25(OH)-vitamin D were determined by electro-hemi-luminescence (Elecsys, Roche Diagnostics). The PTH inhibition rate in % (PTH-IR), the calcium increment, the ratio R (ΔPTH/ΔCalcium) and the product P (calcium X PTH at test end) were calculated.
<bold>Results:</bold> 23 patients with PHPT had complete data from calcium loading tests. The PTH suppression was &lt; 30% in 17.4% of the participants, 30% to 50% – in 21.7% and > 50% in the remaining 60.9%. One patient displayed PTH suppression > 75%. The Ratio R was &lt; 4.0 in all but one patient. Product P was above 1100 mg/dl x pg/ml in 9 participants (39.1%). Sixteen patients (69.6%) had positive localization results from US or SPECT-CT. The level of PTH suppression was not related to any parameter except the volume of the suspected lesion.
<bold>Conclusion:</bold> The calcium loading test was unable to differentiate the forms of PHPT. It did not add great value in the diagnostic work-up of PHPT.
</abstract>

Objective: to describe the results from intravenous calcium loads in patients with suspected PHPT.
Methods: This was a retrospective cross-sectional study with inpatients’ data review. Baseline serum calcium, phosphates, magnesium, creatinine, alkaline phosphatase, beta-crosslinks were recorded. The calcium loading had been performed after an overnight fasting. Calcium gluconate 0.25 mmol/kg body weight (10 mg/kg) dissolved in 0.9% Sodium Chloride was infused intravenously for 3 hours. Blood samples for total serum calcium, phosphates and iPTH were drawn before and up to 60 minutes after the calcium load. The intact parathyroid hormone (iPTH) and 25(OH)-vitamin D were determined by electro-hemi-luminescence (Elecsys, Roche Diagnostics). The PTH inhibition rate in % (PTH-IR), the calcium increment, the ratio R (ΔPTH/ΔCalcium) and the product P (calcium X PTH at test end) were calculated.
Results: 23 patients with PHPT had complete data from calcium loading tests. The PTH suppression was < 30% in 17.4% of the participants, 30% to 50% – in 21.7% and > 50% in the remaining 60.9%. One patient displayed PTH suppression > 75%. The Ratio R was < 4.0 in all but one patient. Product P was above 1100 mg/dl x pg/ml in 9 participants (39.1%). Sixteen patients (69.6%) had positive localization results from US or SPECT-CT. The level of PTH suppression was not related to any parameter except the volume of the suspected lesion.
Conclusion: The calcium loading test was unable to differentiate the forms of PHPT. It did not add great value in the diagnostic work-up of PHPT.

The Calcium Loading Test in Primary Hyperparathyroidism – Does it Provide Useful Information?

Clinic of Endocrinology and Metabolism, University Hospital “Alexandrovska”

Department of Internal Medicine, Faculty of Medicine, Medical University – Sofia

Acta Medica Bulgarica

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Objective: to describe the results from intravenous calcium loads in patients with suspected PHPT.
Methods: This was a retrospective cross-sectional study with inpatients’ data review. Baseline serum calcium, phosphates, magnesium, creatinine, alkaline phosphatase, beta-crosslinks were recorded. The calcium loading had been performed after an overnight fasting. Calcium gluconate 0.25 mmol/kg body weight (10 mg/kg) dissolved in 0.9% Sodium Chloride was infused intravenously for 3 hours. Blood samples for total serum calcium, phosphates and iPTH were drawn before and up to 60 minutes after the calcium load. The intact parathyroid hormone (iPTH) and 25(OH)-vitamin D were determined by electro-hemi-luminescence (Elecsys, Roche Diagnostics). The PTH inhibition rate in % (PTH-IR), the calcium increment, the ratio R (ΔPTH/ΔCalcium) and the product P (calcium X PTH at test end) were calculated.
Results: 23 patients with PHPT had complete data from calcium loading tests. The PTH suppression was 50% in the remaining 60.9%. One patient displayed PTH suppression > 75%. The Ratio R was < 4.0 in all but one patient. Product P was above 1100 mg/dl x pg/ml in 9 participants (39.1%). Sixteen patients (69.6%) had positive localization results from US or SPECT-CT. The level of PTH suppression was not related to any parameter except the volume of the suspected lesion.
Conclusion: The calcium loading test was unable to differentiate the forms of PHPT. It did not add great value in the diagnostic work-up of PHPT.

Objective: to describe the results from intravenous calcium loads in patients with suspected PHPT.
Methods: This was a retrospective cross-sectional study with...

The Calcium Loading Test in Primary Hyperparathyroidism – Does it Provide Useful Information?

Published Online: Oct 26, 2022

Page range: 5 - 11

Received: Sep 02, 2022

Accepted: Sep 20, 2022

DOI: https://doi.org/10.2478/amb-2022-0023

Keywords
primary hyperparathyroidism, laboratory findings, localization studies, calcium loading test

© 2022 D. Bakalov et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

The Calcium Loading Test in Primary Hyperparathyroidism – Does it Provide Useful Information?

Published Online: Oct 26, 2022

Page range: 5 - 11

Received: Sep 02, 2022

Accepted: Sep 20, 2022

DOI: https://doi.org/10.2478/amb-2022-0023

Keywordsprimary hyperparathyroidism, laboratory findings, localization studies, calcium loading test

© 2022 D. Bakalov et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Keywords
primary hyperparathyroidism, laboratory findings, localization studies, calcium loading test