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Total serum calcium reference intervals in postmenopausal outpatients
M J Tanasijevic1, E Ginsburg, D R Wybenga
1Department of Pathology and Clinical Laboratories, Brigham and Women's Hospital, Boston, Mass. 02115, USA.
Insights
Serum calcium levels are higher in postmenopausal women, suggesting a need for adjusted reference intervals. This study analyzed serum calcium in various adult groups to determine appropriate ranges for accurate diagnosis.
Area of Science:
- Endocrinology
- Clinical Chemistry
- Gerontology
Background:
- Serum calcium levels are critical for various physiological functions.
- Established reference intervals for serum calcium may not adequately account for demographic variations.
- Age and menopausal status can influence calcium homeostasis.
Purpose of the Study:
- To investigate the distribution of serum calcium values in distinct outpatient populations.
- To determine if current reference intervals for serum calcium are appropriate across different demographic groups.
- To assess the impact of menopausal status and age on serum calcium levels.
Main Methods:
- Serum calcium levels were measured in four groups: premenopausal women, postmenopausal women, men under 50, and men over 55.
- Average total serum calcium and reference intervals were calculated for each group.
- Statistical comparisons were made between groups to identify significant differences.
Main Results:
- Postmenopausal women exhibited significantly higher average total serum calcium (9.56 mg/dl) compared to premenopausal women (9.42 mg/dl) and older men (9.45 mg/dl).
- A higher percentage of postmenopausal women (8%) had serum calcium levels above the current reference interval compared to premenopausal women (1.7%) and older men (3.3%).
- Reference intervals for total serum calcium were established as 8.4-10.3 mg/dl for premenopausal women, 8.4-10.7 mg/dl for postmenopausal women, 8.6-10.5 mg/dl for younger men, and 8.4-10.4 mg/dl for older men.
Conclusions:
- Age-related increases in total serum calcium are evident in postmenopausal female outpatients.
- The findings support the need for a higher upper limit in the reference interval for total serum calcium in postmenopausal women.
- Adjusting reference intervals based on demographic factors like menopausal status can improve diagnostic accuracy.
Abstract:
The distribution of values of serum calcium has been studied in the following four outpatient populations: premenopausal (n = 411) and postmenopausal women (n = 399), men less than 50 years old (n = 365) and men over 55 years old (n = 361). Their respective average total serum calcium values (mg/dl) were 9.42, 9.56, 9.53, and 9.45. The reference intervals derived for total serum calcium (mg/dl) were 8.4-10.3 (premenopausal women), 8.4-10.7 (postmenopausal women), 8.6-10.5 (men less than 50 years old), and 8.4-10.4 (men over 55 years old). Increased total serum calcium levels were observed in the postmenopausal women as compared with both premenopausal women (p < 0.001) and with men over 55 years old (p < 0.003). Eight percent of the values obtained in postmenopausal women were above the current reference interval, as compared to 1.7% in premenopausal women, and 3.3% in men over 55 years old. In conclusion, the age-related increase in total serum calcium in postmenopausal female outpatients warrants a higher upper limit of the reference interval for this subpopulation.