Hyperparathyroidism laboratory findings: Difference between revisions
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__NOTOC__ | __NOTOC__ | ||
{{Hyperparathyroidism}} | {{Hyperparathyroidism}} | ||
{{CMG}}; {{AE}} | {{CMG}}; {{AE}} {{Anmol}} | ||
==Overview== | ==Overview== | ||
An elevated | An elevated serum [[calcium]] on routine biochemical screening in a asymptomatic patient should raise the suspicion of primary hyperparathyroidism. An elevated concentration of serum [[calcium]] with elevated [[parathyroid hormone]] level is diagnostic of primary hyperparathyoidism. Most consistent laboratory findings associated with the diagnosis of secondary hyperparathyroidism include elevated serum [[parathyroid hormone]] level and low to normal serum [[calcium]]. An elevated concentration of serum [[calcium]] with elevated [[parathyroid hormone]] level in post [[Kidney transplantation|renal transplant]] patients is diagnostic of tertiary hyperparathyoidism. Measurement of total serum [[calcium]] with automatic techniques has similar or even more reliability than serum ionized [[calcium]] measurement. Method of choice for measuring intact [[parathyroid hormone]] include Immunoradiometric assay (IMRA) or Immunochemiluminescent assay (ICMA). 24-Hour [[urinary]] [[calcium]] [[excretion]] is used to seperate the patients with [[familial hypocalciuric hypercalcemia]] and typical primary hyperparathyroidism. Serum [[1,25-dihydroxy vitamin D]] ([[calcitriol]]) concentration are significantly lower in familial hypocalciuric hypercalcemia than primary hyperparathyroidism. | ||
[ | |||
==Laboratory Findings== | ==Laboratory Findings== | ||
===Primary hyperparathyroidism=== | ===Primary hyperparathyroidism=== | ||
*An elevated serum calcium on routine biochemical screening in a asymptomatic patient should raise the suspicion of primary hyperparathyroidism.<ref name="pmid8964825">{{cite journal |vauthors=Silverberg SJ, Bilezikian JP |title=Evaluation and management of primary hyperparathyroidism |journal=J. Clin. Endocrinol. Metab. |volume=81 |issue=6 |pages=2036–40 |year=1996 |pmid=8964825 |doi=10.1210/jcem.81.6.8964825 |url=https://watermark.silverchair.com/api/watermark?token=AQECAHi208BE49Ooan9kkhW_Ercy7Dm3ZL_9Cf3qfKAc485ysgAAAfQwggHwBgkqhkiG9w0BBwagggHhMIIB3QIBADCCAdYGCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMs2QB8t_zFXzSZJ4bAgEQgIIBp8fw3_iunlmFW1rMhoY9MDPeg_lHu7iYzuIrfwXHubghqdXOMvdWyttCOOgR3PHFZtE5IkmNB4hRahVQsPzHGwh5kiBmLGp9W8OQwFxrCIH0sBqjOxOiYc_yGAs0ybxF1mEh929-YxivBBC43EW1yFtSmwplSQfAWah7w6yxXbUhV8umq3pGQxqYDClp47IR7TyVeEneWZz85Z7MS80V4c-yZPG1ZPxQR-1kPk3rdji_8bAeXwJKRGScWzKPqSEQvXFWLV4sHwqgTrU53HSkURUJb8u-w4EOHMjtUATJPoGgFsZOcrf_xtPBZmcI_v5G3RO_cJDHueDwQNfRaGIO2ztcToFGmVpER4vGhqfrtr7mXHPNPyUUOa-_KWPE-qxDrUCG8kevm0tM8MButJkAmVdBxrIC4mSd8sAZb3KcfSKt9RUXFJpIiDoOut21ZFEGEU8O7vwjw4RhxridsegEUiCFWCxHftX9qUqELn90AJ2Fg1olxH9jI46KnEJPd7MNYReTvdeX5erBZmXjmP5oCT6vLYUbRLjXxyJQRl-d5N9O0vfTgZ5bbA}}</ref> | *An elevated serum [[calcium]] on routine biochemical screening in a asymptomatic patient should raise the suspicion of primary hyperparathyroidism.<ref name="pmid8964825">{{cite journal |vauthors=Silverberg SJ, Bilezikian JP |title=Evaluation and management of primary hyperparathyroidism |journal=J. Clin. Endocrinol. Metab. |volume=81 |issue=6 |pages=2036–40 |year=1996 |pmid=8964825 |doi=10.1210/jcem.81.6.8964825 |url=https://watermark.silverchair.com/api/watermark?token=AQECAHi208BE49Ooan9kkhW_Ercy7Dm3ZL_9Cf3qfKAc485ysgAAAfQwggHwBgkqhkiG9w0BBwagggHhMIIB3QIBADCCAdYGCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMs2QB8t_zFXzSZJ4bAgEQgIIBp8fw3_iunlmFW1rMhoY9MDPeg_lHu7iYzuIrfwXHubghqdXOMvdWyttCOOgR3PHFZtE5IkmNB4hRahVQsPzHGwh5kiBmLGp9W8OQwFxrCIH0sBqjOxOiYc_yGAs0ybxF1mEh929-YxivBBC43EW1yFtSmwplSQfAWah7w6yxXbUhV8umq3pGQxqYDClp47IR7TyVeEneWZz85Z7MS80V4c-yZPG1ZPxQR-1kPk3rdji_8bAeXwJKRGScWzKPqSEQvXFWLV4sHwqgTrU53HSkURUJb8u-w4EOHMjtUATJPoGgFsZOcrf_xtPBZmcI_v5G3RO_cJDHueDwQNfRaGIO2ztcToFGmVpER4vGhqfrtr7mXHPNPyUUOa-_KWPE-qxDrUCG8kevm0tM8MButJkAmVdBxrIC4mSd8sAZb3KcfSKt9RUXFJpIiDoOut21ZFEGEU8O7vwjw4RhxridsegEUiCFWCxHftX9qUqELn90AJ2Fg1olxH9jI46KnEJPd7MNYReTvdeX5erBZmXjmP5oCT6vLYUbRLjXxyJQRl-d5N9O0vfTgZ5bbA}}</ref> | ||
*An elevated | *An elevated concentration of serum [[calcium]] with elevated [[parathyroid hormone]] level is diagnostic of primary hyperparathyroidism. | ||
*25-Hydroxy vitamin D is usually normal among patients with primary hyperparathyroidism. | *25-Hydroxy vitamin D is usually normal among patients with primary hyperparathyroidism. | ||
*Laboratory findings consistent with the diagnosis of primary hyperparathyroidism include | *Laboratory findings consistent with the diagnosis of primary hyperparathyroidism include: | ||
**Elevated concentration of serum calcium | **Elevated concentration of serum [[calcium]] | ||
**Elevated serum parathyroid level | **Elevated serum [[parathyroid hormone]] level | ||
**Low normal serum | **Low normal serum [[phosphate]] concentration | ||
**Elevated 1,25-dihydroxy vitamin D (calcitriol) may be found in around half of patients. | **Elevated [[1,25-dihydroxy vitamin D]] ([[calcitriol]]) may be found in around half of patients. | ||
**There is a mild elevation in bone turnover indices including serum alkaline | **There is a mild elevation in bone turnover indices including serum [[alkaline phosphatase]] activity, [[osteocalcin]], and urinary hydroxypiridinium [[collagen]] crosslinks. | ||
===Secondary hyperparathyroidism=== | ===Secondary hyperparathyroidism=== | ||
*Laboratory findings consistent with the diagnosis of secondary hyperparathyroidism include: | *Laboratory findings consistent with the diagnosis of secondary hyperparathyroidism include: | ||
**Elevated serum parathyroid hormone level | **Elevated serum [[parathyroid hormone]] level | ||
**Low to normal serum calcium | **Low to normal serum [[calcium]] | ||
**Low serum vitamin D (25-hydroxy vitamin D) may be found if vitamin D deficiency is the cause of secondary hyperparathyroidism. | **Low serum [[vitamin D]] (25-hydroxy vitamin D) may be found if [[vitamin D deficiency]] is the cause of secondary hyperparathyroidism. | ||
**Elevated serum [[phosphate]] | |||
===Tertiary hyperparathyroidism=== | ===Tertiary hyperparathyroidism=== | ||
*An elevated concentration of serum calcium with elevated parathyroid level in post renal transplant patients is diagnostic of tertiary hyperparathyoidism. | *An elevated concentration of serum [[calcium]] with elevated [[parathyroid hormone]] level in post [[Kidney transplantation|renal transplant]] patients is diagnostic of tertiary hyperparathyoidism. | ||
{| | *Elevated serum [[phosphate]] is also present. | ||
{| | |||
! rowspan="2" style="background: #4479BA; text-align: center;" |{{fontcolor|#FFF|Laboratory findings}} | ! rowspan="2" style="background: #4479BA; text-align: center;" |{{fontcolor|#FFF|Laboratory findings}} | ||
! colspan="3" style="background: #4479BA; text-align: center;" |{{fontcolor|#FFF|Hyperparathyroisidm}} | ! colspan="3" style="background: #4479BA; text-align: center;" |{{fontcolor|#FFF|Hyperparathyroisidm}} | ||
| Line 50: | Line 36: | ||
| style="background: #7d7d7d; text-align: center;" |{{fontcolor|#FFF|Tertiary hyperparathyroidism}} | | style="background: #7d7d7d; text-align: center;" |{{fontcolor|#FFF|Tertiary hyperparathyroidism}} | ||
|- | |- | ||
| style="background: # | | style="background: #DCDCDC; text-align: center;" |Parathyroid hormone | ||
| style="background: # | | style="background: #F5F5F5; text-align: center;" |'''↑''' | ||
| style="background: # | | style="background: #F5F5F5; text-align: center;" |'''↑''' | ||
| style="background: # | | style="background: #F5F5F5; text-align: center;" |'''↑''' | ||
|- | |- | ||
| style="background: # | | style="background: #DCDCDC; text-align: center;" |Serum calcium | ||
| style="background: # | | style="background: #F5F5F5; text-align: center;" |'''↑''' | ||
| style="background: #DCDCDC; text-align: center;" |'''↓''' | | style="background: #F5F5F5; text-align: center;" |'''↓'''/Normal | ||
| style="background: # | | style="background: #F5F5F5; text-align: center;" |'''↑''' | ||
|- | |||
| style="background: #DCDCDC; text-align: center;" |Serum phosphate | |||
| style="background: #F5F5F5; text-align: center;" |'''↓'''/Normal | |||
| style="background: #F5F5F5; text-align: center;" |'''↑''' | |||
| style="background: #F5F5F5; text-align: center;" |'''↑''' | |||
|} | |} | ||
==Biochemical Tests== | ==Biochemical Tests== | ||
===Serum Calcium=== | ===Serum Calcium=== | ||
*An elevated serum | *An elevated serum [[calcium]] on routine biochemical screening in a asymptomatic patient should raise the suspicion of primary hyperparathyroidism.<ref name="pmid8964825">{{cite journal |vauthors=Silverberg SJ, Bilezikian JP |title=Evaluation and management of primary hyperparathyroidism |journal=J. Clin. Endocrinol. Metab. |volume=81 |issue=6 |pages=2036–40 |year=1996 |pmid=8964825 |doi=10.1210/jcem.81.6.8964825 |url=https://watermark.silverchair.com/api/watermark?token=AQECAHi208BE49Ooan9kkhW_Ercy7Dm3ZL_9Cf3qfKAc485ysgAAAfQwggHwBgkqhkiG9w0BBwagggHhMIIB3QIBADCCAdYGCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMs2QB8t_zFXzSZJ4bAgEQgIIBp8fw3_iunlmFW1rMhoY9MDPeg_lHu7iYzuIrfwXHubghqdXOMvdWyttCOOgR3PHFZtE5IkmNB4hRahVQsPzHGwh5kiBmLGp9W8OQwFxrCIH0sBqjOxOiYc_yGAs0ybxF1mEh929-YxivBBC43EW1yFtSmwplSQfAWah7w6yxXbUhV8umq3pGQxqYDClp47IR7TyVeEneWZz85Z7MS80V4c-yZPG1ZPxQR-1kPk3rdji_8bAeXwJKRGScWzKPqSEQvXFWLV4sHwqgTrU53HSkURUJb8u-w4EOHMjtUATJPoGgFsZOcrf_xtPBZmcI_v5G3RO_cJDHueDwQNfRaGIO2ztcToFGmVpER4vGhqfrtr7mXHPNPyUUOa-_KWPE-qxDrUCG8kevm0tM8MButJkAmVdBxrIC4mSd8sAZb3KcfSKt9RUXFJpIiDoOut21ZFEGEU8O7vwjw4RhxridsegEUiCFWCxHftX9qUqELn90AJ2Fg1olxH9jI46KnEJPd7MNYReTvdeX5erBZmXjmP5oCT6vLYUbRLjXxyJQRl-d5N9O0vfTgZ5bbA}}</ref> | ||
*Measurement of total serum calcium with automatic techniques has similar or even more reliability than serum ionized calcium measurement. | *Measurement of total serum [[calcium]] with automatic techniques has similar or even more reliability than serum ionized [[calcium]] measurement. | ||
*An elevated serum calcium should be confirmed by repeat measurement. | *An elevated serum [[calcium]] should be confirmed by repeat measurement. | ||
*20% of patients with proven primary hyperparathyroidism have normal total calcium and elevated parathyroid hormone. Serum ionized concentration measurement is helpful in such cases.<ref name="pmid9612524">{{cite journal |vauthors=Glendenning P, Gutteridge DH, Retallack RW, Stuckey BG, Kermode DG, Kent GN |title=High prevalence of normal total calcium and intact PTH in 60 patients with proven primary hyperparathyroidism: a challenge to current diagnostic criteria |journal=Aust N Z J Med |volume=28 |issue=2 |pages=173–8 |year=1998 |pmid=9612524 |doi= |url=}}</ref> | *20% of patients with proven primary hyperparathyroidism have normal total [[calcium]] and elevated [[parathyroid hormone]]. Serum ionized concentration measurement is helpful in such cases.<ref name="pmid9612524">{{cite journal |vauthors=Glendenning P, Gutteridge DH, Retallack RW, Stuckey BG, Kermode DG, Kent GN |title=High prevalence of normal total calcium and intact PTH in 60 patients with proven primary hyperparathyroidism: a challenge to current diagnostic criteria |journal=Aust N Z J Med |volume=28 |issue=2 |pages=173–8 |year=1998 |pmid=9612524 |doi= |url=}}</ref> | ||
*Some patients with primary hyperparathyroidism may have elevated concentration of serum parathyroid hormone with normal serum calcium, which is usually suggestive of normocalcemic | *Some patients with primary hyperparathyroidism may have elevated concentration of serum [[parathyroid hormone]] with normal serum [[calcium]], which is usually suggestive of normocalcemic primary hyperparathyroidism.<ref name="pmid19193910">{{cite journal |vauthors=Silverberg SJ, Lewiecki EM, Mosekilde L, Peacock M, Rubin MR |title=Presentation of asymptomatic primary hyperparathyroidism: proceedings of the third international workshop |journal=J. Clin. Endocrinol. Metab. |volume=94 |issue=2 |pages=351–65 |year=2009 |pmid=19193910 |pmc=5393372 |doi=10.1210/jc.2008-1760 |url=}}</ref> Causes of secondary hyperparathyroidism should be rules out for making the diagnosis of normocalcemic primary hyperparathyroidism. Normocalcemic primary hyperparathyroidism might represent the first symptomatic stage of primary hyperparathyroidism.<ref name="pmid17536001">{{cite journal |vauthors=Lowe H, McMahon DJ, Rubin MR, Bilezikian JP, Silverberg SJ |title=Normocalcemic primary hyperparathyroidism: further characterization of a new clinical phenotype |journal=J. Clin. Endocrinol. Metab. |volume=92 |issue=8 |pages=3001–5 |year=2007 |pmid=17536001 |doi=10.1210/jc.2006-2802 |url=}}</ref> | ||
===Chloride phosphate ratio=== | |||
The serum chloride phosphate ratio is high (33 or more) in most patients with primary hyperparathyroidism. <ref name="pmid1155729">{{cite journal |author=Reeves CD, Palmer F, Bacchus H, Longerbeam JK |title=Differential diagnosis of hypercalcemia by the chloride/phosphate ratio |journal=Am. J. Surg. |volume=130 |issue=2 |pages=166-71 |year=1975 |pmid=1155729 |doi=}}<br><blockquote>This study found a ratio above 33 to have a [[sensitivity (tests)|sensitivity]] of 94% and a [[specificity (tests)|specificity]] of 96%.</blockquote></ref><ref name="pmid4405880">{{cite journal |author=Palmer FJ, Nelson JC, Bacchus H |title=The chloride-phosphate ratio in hypercalcemia |journal=Ann. Intern. Med. |volume=80 |issue=2 |pages=200-4 |year=1974 |pmid=4405880 |doi=}}</ref><ref name="pmid521012">{{cite journal |author=Broulík PD, Pacovský V |title=The chloride phosphate ratio as the screening test for primary hyperparathyroidism |journal=Horm. Metab. Res. |volume=11 |issue=10 |pages=577-9 |year=1979 |pmid=521012 |doi=}}<br><blockquote>This study found a ratio above 33 to have a [[sensitivity (tests)|sensitivity]] of 95% and a [[specificity (tests)|specificity]] of 100%.</blockquote></ref> However, [[thiazide]] medications have been reported to causes ratios above 33.<ref name="pmid6848626">{{cite journal |author=Lawler FH, Janssen HP |title=Chloride:phosphate ratio with hypercalcemia secondary to thiazide administration |journal=The Journal of family practice |volume=16 |issue=1 |pages=153-4 |year=1983 |pmid=6848626 |doi=}}</ref>. | |||
===Serum Parathyroid hormone=== | ===Serum Parathyroid hormone=== | ||
*Method of choice for measuring intact parathyroid hormone include Immunoradiometric assay(IMRA) or Immunochemiluminescent assay(ICMA).<ref name="pmid1993319">{{cite journal |vauthors=Endres DB, Villanueva R, Sharp CF, Singer FR |title=Immunochemiluminometric and immunoradiometric determinations of intact and total immunoreactive parathyrin: performance in the differential diagnosis of hypercalcemia and hypoparathyroidism |journal=Clin. Chem. |volume=37 |issue=2 |pages=162–8 |year=1991 |pmid=1993319 |doi= |url=http://clinchem.aaccjnls.org/content/clinchem/37/2/162.full.pdf}}</ref> | *Method of choice for measuring intact parathyroid hormone include Immunoradiometric assay (IMRA) or Immunochemiluminescent assay (ICMA).<ref name="pmid1993319">{{cite journal |vauthors=Endres DB, Villanueva R, Sharp CF, Singer FR |title=Immunochemiluminometric and immunoradiometric determinations of intact and total immunoreactive parathyrin: performance in the differential diagnosis of hypercalcemia and hypoparathyroidism |journal=Clin. Chem. |volume=37 |issue=2 |pages=162–8 |year=1991 |pmid=1993319 |doi= |url=http://clinchem.aaccjnls.org/content/clinchem/37/2/162.full.pdf}}</ref> | ||
===24-Hour urinary calcium=== | ===24-Hour urinary calcium=== | ||
*24-Hour urinary calcium excretion is indicated by the calcium:creatinine clearance ratio.<ref name="pmid7356229">{{cite journal |vauthors=Marx SJ, Stock JL, Attie MF, Downs RW, Gardner DG, Brown EM, Spiegel AM, Doppman JL, Brennan MF |title=Familial hypocalciuric hypercalcemia: recognition among patients referred after unsuccessful parathyroid exploration |journal=Ann. Intern. Med. |volume=92 |issue=3 |pages=351–6 |year=1980 |pmid=7356229 |doi= |url=}}</ref><ref name="pmid686009">{{cite journal |vauthors=Marx SJ, Spiegel AM, Brown EM, Koehler JO, Gardner DG, Brennan MF, Aurbach GD |title=Divalent cation metabolism. Familial hypocalciuric hypercalcemia versus typical primary hyperparathyroidism |journal=Am. J. Med. |volume=6http://www.sciencedirect.com/science/article/pii/0002934378908148?via%3Dihub5 |issue=2 |pages=235–42 |year=1978 |pmid=686009 |doi=10.1016/0002-9343(78)90814-8 |url=}}</ref> | *24-Hour urinary [[calcium]] excretion is indicated by the urinary calcium:creatinine clearance ratio.<ref name="pmid7356229">{{cite journal |vauthors=Marx SJ, Stock JL, Attie MF, Downs RW, Gardner DG, Brown EM, Spiegel AM, Doppman JL, Brennan MF |title=Familial hypocalciuric hypercalcemia: recognition among patients referred after unsuccessful parathyroid exploration |journal=Ann. Intern. Med. |volume=92 |issue=3 |pages=351–6 |year=1980 |pmid=7356229 |doi= |url=}}</ref><ref name="pmid686009">{{cite journal |vauthors=Marx SJ, Spiegel AM, Brown EM, Koehler JO, Gardner DG, Brennan MF, Aurbach GD |title=Divalent cation metabolism. Familial hypocalciuric hypercalcemia versus typical primary hyperparathyroidism |journal=Am. J. Med. |volume=6http://www.sciencedirect.com/science/article/pii/0002934378908148?via%3Dihub5 |issue=2 |pages=235–42 |year=1978 |pmid=686009 |doi=10.1016/0002-9343(78)90814-8 |url=}}</ref> | ||
*It is used to seperate the patients with familial hypocalciuric hypercalcemia and typical primary hyperparathyroidism. | *It is used to seperate the patients with [[familial hypocalciuric hypercalcemia]] and typical primary hyperparathyroidism. | ||
===Serum 1,25-dihydroxy vitamin D=== | ===Serum 1,25-dihydroxy vitamin D=== | ||
*May be used to differentiate between Familial | *May be used to differentiate between Familial hypercalciuric hypercalcemia (FHH) with primary hyperparathyroidism.<ref name="pmid6699136">{{cite journal |vauthors=Law WM, Bollman S, Kumar R, Heath H |title=Vitamin D metabolism in familial benign hypercalcemia (hypocalciuric hypercalcemia) differs from that in primary hyperparathyroidism |journal=J. Clin. Endocrinol. Metab. |volume=58 |issue=4 |pages=744–7 |year=1984 |pmid=6699136 |doi=10.1210/jcem-58-4-744 |url=}}</ref><ref name="pmid18787045">{{cite journal |vauthors=Christensen SE, Nissen PH, Vestergaard P, Heickendorff L, Rejnmark L, Brixen K, Mosekilde L |title=Plasma 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and parathyroid hormone in familial hypocalciuric hypercalcemia and primary hyperparathyroidism |journal=Eur. J. Endocrinol. |volume=159 |issue=6 |pages=719–27 |year=2008 |pmid=18787045 |doi=10.1530/EJE-08-0440 |url=http://www.eje-online.org/content/159/6/719.full.pdf}}</ref> | ||
*Serum 1,25-dihydroxy vitamin D (calcitriol) concentration are significantly lower in FHH than primary hyperparathyroidism. | *Serum [[1,25-dihydroxy vitamin D]] ([[calcitriol]]) concentration are significantly lower in FHH than primary hyperparathyroidism. | ||
==References== | ==References== | ||
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[[Category:Disease]] | |||
[[Category:Medicine]] | |||
[[Category:Endocrinology]] | |||
[[Category:Parathyroid disorders]] | |||
[[Category:Up-To-Date]] | |||
Latest revision as of 22:16, 29 July 2020
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Hyperparathyroidism Microchapters |
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Hyperparathyroidism laboratory findings On the Web |
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American Roentgen Ray Society Images of Hyperparathyroidism laboratory findings |
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Risk calculators and risk factors for Hyperparathyroidism laboratory findings |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Anmol Pitliya, M.B.B.S. M.D.[2]
Overview
An elevated serum calcium on routine biochemical screening in a asymptomatic patient should raise the suspicion of primary hyperparathyroidism. An elevated concentration of serum calcium with elevated parathyroid hormone level is diagnostic of primary hyperparathyoidism. Most consistent laboratory findings associated with the diagnosis of secondary hyperparathyroidism include elevated serum parathyroid hormone level and low to normal serum calcium. An elevated concentration of serum calcium with elevated parathyroid hormone level in post renal transplant patients is diagnostic of tertiary hyperparathyoidism. Measurement of total serum calcium with automatic techniques has similar or even more reliability than serum ionized calcium measurement. Method of choice for measuring intact parathyroid hormone include Immunoradiometric assay (IMRA) or Immunochemiluminescent assay (ICMA). 24-Hour urinary calcium excretion is used to seperate the patients with familial hypocalciuric hypercalcemia and typical primary hyperparathyroidism. Serum 1,25-dihydroxy vitamin D (calcitriol) concentration are significantly lower in familial hypocalciuric hypercalcemia than primary hyperparathyroidism.
Laboratory Findings
Primary hyperparathyroidism
- An elevated serum calcium on routine biochemical screening in a asymptomatic patient should raise the suspicion of primary hyperparathyroidism.[1]
- An elevated concentration of serum calcium with elevated parathyroid hormone level is diagnostic of primary hyperparathyroidism.
- 25-Hydroxy vitamin D is usually normal among patients with primary hyperparathyroidism.
- Laboratory findings consistent with the diagnosis of primary hyperparathyroidism include:
- Elevated concentration of serum calcium
- Elevated serum parathyroid hormone level
- Low normal serum phosphate concentration
- Elevated 1,25-dihydroxy vitamin D (calcitriol) may be found in around half of patients.
- There is a mild elevation in bone turnover indices including serum alkaline phosphatase activity, osteocalcin, and urinary hydroxypiridinium collagen crosslinks.
Secondary hyperparathyroidism
- Laboratory findings consistent with the diagnosis of secondary hyperparathyroidism include:
- Elevated serum parathyroid hormone level
- Low to normal serum calcium
- Low serum vitamin D (25-hydroxy vitamin D) may be found if vitamin D deficiency is the cause of secondary hyperparathyroidism.
- Elevated serum phosphate
Tertiary hyperparathyroidism
- An elevated concentration of serum calcium with elevated parathyroid hormone level in post renal transplant patients is diagnostic of tertiary hyperparathyoidism.
- Elevated serum phosphate is also present.
| Laboratory findings | Hyperparathyroisidm | ||
|---|---|---|---|
| Primary hyperparathyroidism | Secondary hyperparathyroidism | Tertiary hyperparathyroidism | |
| Parathyroid hormone | ↑ | ↑ | ↑ |
| Serum calcium | ↑ | ↓/Normal | ↑ |
| Serum phosphate | ↓/Normal | ↑ | ↑ |
Biochemical Tests
Serum Calcium
- An elevated serum calcium on routine biochemical screening in a asymptomatic patient should raise the suspicion of primary hyperparathyroidism.[1]
- Measurement of total serum calcium with automatic techniques has similar or even more reliability than serum ionized calcium measurement.
- An elevated serum calcium should be confirmed by repeat measurement.
- 20% of patients with proven primary hyperparathyroidism have normal total calcium and elevated parathyroid hormone. Serum ionized concentration measurement is helpful in such cases.[2]
- Some patients with primary hyperparathyroidism may have elevated concentration of serum parathyroid hormone with normal serum calcium, which is usually suggestive of normocalcemic primary hyperparathyroidism.[3] Causes of secondary hyperparathyroidism should be rules out for making the diagnosis of normocalcemic primary hyperparathyroidism. Normocalcemic primary hyperparathyroidism might represent the first symptomatic stage of primary hyperparathyroidism.[4]
Chloride phosphate ratio
The serum chloride phosphate ratio is high (33 or more) in most patients with primary hyperparathyroidism. [5][6][7] However, thiazide medications have been reported to causes ratios above 33.[8].
Serum Parathyroid hormone
- Method of choice for measuring intact parathyroid hormone include Immunoradiometric assay (IMRA) or Immunochemiluminescent assay (ICMA).[9]
24-Hour urinary calcium
- 24-Hour urinary calcium excretion is indicated by the urinary calcium:creatinine clearance ratio.[10][11]
- It is used to seperate the patients with familial hypocalciuric hypercalcemia and typical primary hyperparathyroidism.
Serum 1,25-dihydroxy vitamin D
- May be used to differentiate between Familial hypercalciuric hypercalcemia (FHH) with primary hyperparathyroidism.[12][13]
- Serum 1,25-dihydroxy vitamin D (calcitriol) concentration are significantly lower in FHH than primary hyperparathyroidism.
References
- ↑ 1.0 1.1 Silverberg SJ, Bilezikian JP (1996). "Evaluation and management of primary hyperparathyroidism". J. Clin. Endocrinol. Metab. 81 (6): 2036–40. doi:10.1210/jcem.81.6.8964825. PMID 8964825.
- ↑ Glendenning P, Gutteridge DH, Retallack RW, Stuckey BG, Kermode DG, Kent GN (1998). "High prevalence of normal total calcium and intact PTH in 60 patients with proven primary hyperparathyroidism: a challenge to current diagnostic criteria". Aust N Z J Med. 28 (2): 173–8. PMID 9612524.
- ↑ Silverberg SJ, Lewiecki EM, Mosekilde L, Peacock M, Rubin MR (2009). "Presentation of asymptomatic primary hyperparathyroidism: proceedings of the third international workshop". J. Clin. Endocrinol. Metab. 94 (2): 351–65. doi:10.1210/jc.2008-1760. PMC 5393372. PMID 19193910.
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This study found a ratio above 33 to have a sensitivity of 94% and a specificity of 96%.
- ↑ Palmer FJ, Nelson JC, Bacchus H (1974). "The chloride-phosphate ratio in hypercalcemia". Ann. Intern. Med. 80 (2): 200–4. PMID 4405880.
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This study found a ratio above 33 to have a sensitivity of 95% and a specificity of 100%.
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