Hypocalcemia laboratory findings
Resident Survival Guide |
Hypocalcemia Microchapters |
Diagnosis |
---|
Treatment |
Case Studies |
Hypocalcemia laboratory findings On the Web |
American Roentgen Ray Society Images of Hypocalcemia laboratory findings |
Risk calculators and risk factors for Hypocalcemia laboratory findings |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: hypocalcaemia; low serum calcium level
Overview
Laboratory investigations that detect alterations in PTH, vitamin D, and phosphate in the serum or urine aid in the differential diagnosis of the underlying etiologies.
Measurement of the serum albumin concentration is essential to distinguish pseudohypocalcemia from true hypocalcemia.
Other laboratory tests include serum alkaline phosphates, liver function tests, coagulation profile, blood urea nitrogen, creatinine and urinary cAMP levels at baseline and after PTH administration.
Adjustment for Hypoalbuminemia
- Adjustment of total serum calcium concentration for changes in plasma albumin level:[1]
- Adjusted total calcium in mg/dL = Total calcium in mg/dL + 0.8 * (4 - Albumin in g/dL)
- Adjusted total calcium in mmol/L = Total calcium in mmol/L + 0.02 * (40 - Albumin in g/L)
Laboratory Differential Diagnosis of Hypocalcemia
Abbreviations: ADHP, autosomal dominant hypoparathyroidism; cAMP, cyclic adenosine monophosphate; CKD, chronic kidney disease; Cr, creatinine; Def, deficiency; HP, hyperphosphatemia; HPTH, hypoparathyroidism; PHP, pseudohypoparathyroidism; VDDR, vitamin D-dependent rickets.
↓Ca | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
↑PTH | ↔↓PTH | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
↑PO4 | ↔↓PO4 | ↔Mg | ↓Mg | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
↑Cr | ↔Cr | ↓25(OH)D | ↔↑25(OH)D | HPTH | ADHP or Mg def | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
CKD | PHP or HP | Vitamin D def | ↓1,25(OH)2D | ↑1,25(OH)2D | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Type I VDDR | Type II VDDR | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||