What is the role of lab studies in the workup of osteoporosis?

Updated: Sep 26, 2019
  • Author: Monique Bethel, MD; Chief Editor: Herbert S Diamond, MD  more...
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Answer

Laboratory studies are used to establish baseline conditions or to exclude secondary causes of osteoporosis. They are summarized in Tables 5 and 6, below.

Table 5. Baseline Studies for Baseline Conditions in Osteoporosis (Open Table in a new window)

Baseline test

Disorder

Complete blood count (CBC)

CBC results may reveal anemia, as in sickle cell disease (patients with anemia, particularly those older than 60 years, should also be evaluated for multiple myeloma), and may raise the suspicion for alcohol abuse (in conjunction with results from serum chemistry tests and liver function tests)

Serum chemistry levels

Calcium levels can reflect underlying disease states (eg, severe hypercalcemia may reflect underlying malignancy or hyperparathyroidism; hypocalcemia can contribute to osteoporosis)

levels of serum calcium, phosphate, and alkaline phosphatase are usually normal in persons with primary osteoporosis, although alkaline phosphatase levels may be elevated for several months after a fracture

levels of serum calcium, phosphate, alkaline phosphatase, and 25(OH) vitamin D may be obtained to assess osteomalacia

Creatinine levels may decrease with increasing parathyroid hormone (PTH) levels or may be elevated in patients with multiple myeloma

Creatinine levels are also used to estimate creatinine clearance, which may indicate reduced renal function in elderly patients

Magnesium is very important in calcium homeostasis [101] ; decreased levels of magnesium may affect calcium absorption and metabolism

Liver function tests

Increased levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), bilirubin, and alkaline phosphatase may indicate alcohol abuse

Thyroid-stimulating hormone (TSH) level

Thyroid dysfunction has been associated with osteoporosis and should therefore be ruled out [102]

25-Hydroxyvitamin D level

This test assesses for vitamin D insufficiency; inadequate vitamin D levels can predispose persons to osteoporosis

An important study by Tannenbaum evaluated 173 healthy women (ages 46-87 years) for secondary causes of osteoporosis and found that 55 (32%) had a previously undiagnosed disorder of bone or mineral metabolism. [103] Given that occult disorders are so common in patients with osteoporosis, minimal laboratory screening is indicated in all patients who present with decreased bone mass.

Table 6. Tests for Secondary Causes of Osteoporosis (Open Table in a new window)

Tests for Secondary Causes of Osteoporosis

Disorder

24-Hour urine calcium level

This study assesses for hypercalciuria and hypocalciuria

Parathyroid hormone (PTH) level

An intact PTH result is essential in ruling out hyperparathyroidism; an elevated PTH level may be present in benign familial hypocalciuric hypercalcemia

Thyrotropin level (if on thyroid replacement)

Experts are divided on whether to include thyrotropin testing, regardless of a history of thyroid disease or replacement; however, one study showed reduced femoral neck bone mineral density (BMD) in women with subclinical hypothyroidism and hyperthyroidism [102]

Testosterone and gonadotropin levels in younger men with low bone densities

These tests may help evaluate a sex hormone deficiency as a secondary cause of osteoporosis

Urinary free cortisol level and tests for adrenal hypersecretion

These tests are used to exclude Cushing syndrome, which, although uncommon, can lead to rapidly progressive osteoporosis when the condition is present; a urine free cortisol value or overnight dexamethasone suppression test should be ordered in suspected cases

Serum protein electrophoresis (SPEP) and urine protein electrophoresis (UPEP)

These are used to identify multiple myeloma

Antigliadin and antiendomysial antibodies

These tests can help identify celiac disease

Serum tryptase and urine N-methylhistamine

These tests help identify mastocytosis

Bone marrow biopsy

This study is obtained when a hematologic disorder is suspected


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