Vitamin D tests Inaccurate

[myrose]

NewsJournal

Winter 2009

Volume 33, No. 1

Vitamin D Tests Inaccurate

posted at www.consumerist.com

Consumerist, a popular consumer

website, reports that last October,

Quest Diagnostics, one of the

n a t io n ’s la r g e s t me d i c a l

laboratories, contacted "thousands

of doctors" around the country,

regarding possible testing errors.

Quest acknowledged that one or

more of their patients might have

r e c e i v e d

"questionabl

e" results on

vitamin D

t e s t s

p e rf o rme d

over the past two years. It's offering

free retests to anyone who was

affected.

The errors came about when Quest

switched from an FDA-approved

test to "a new test of its own

design," reports the New York

Times.

So what does it mean to have an

incorrect vitamin D analysis?

An erroneously high result may

mean patients will not take vitamin

D supplements when perhaps they

should, doctors said. And an

erroneously low test result might

lead in rare instances to a toxic

overdose of vitamin D. When the

Quest tests have been inaccurate,

the reading has typically been too

high, although not in all cases.

There's at least one case, reported

in the Times article, of a patient

who subsequently tested positive

for a "toxic level" of vitamin D after

his Quest result said he had a

deficiency.

Dr. Salameh, a medical director for

Q u e s t , s a ys the m a s s

spectrometers Quest uses weren't

calibrated properly, and that 4 of the

7 labs didn't always follow proper

procedure. He also notes, however,

that Quest erred on the side of

caution by contacting anyone with

even the slightest chance of a

mistaken test."