Revisiting Variability in Measurement of Vitamin D Levels

On average, serum 25-hydroxyvitamin D levels differed by 5 ng/mL across two assays.

A 2004 study demonstrated that measurements of serum 25-hydroxyvitamin D (25[OH]D) levels are considerably variable across different assays (JW Gen Med Aug 13 2004). Now, researchers at Lebanon's American University of Beirut have revisited this issue. They measured 25(OH)D levels in each of 494 adults using both a radioimmunoassay (Immunodiagnostic Systems RIA; Boldon, U.K.) and an automated chemiluminescent immunoassay (DiaSorin Liaison; Stillwater, Minnesota).

Mean 25(OH)D levels were significantly lower with DiaSorin Liaison than with IDS-RIA (21 vs. 26 ng/mL), and the proportion of people with serum levels measuring <20 ng/mL was significantly higher with DiaSorin Liaison (52% vs. 36%). In 13% of patients, measurements from the two assa…

Reviewing Author

Allan S. Brett, MD

Disclosures

Nothing to disclose

Allan S. Brett, MD

Disclosures

Nothing to disclose

Revisiting Variability in Measurement of Vitamin D Levels

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Reviewing Author