Transcript STT AllYouWanted 07 - STT

All you wanted to know about
laboratory tests, but were afraid to ask
The informed patient
meeting the laboratory director
Standardization & Traceability
The problem
By Dietmar Stöckl
STT Consulting
-7-
Reminder
We heard laboratory testing
would be a good idea,
but ...
All you wanted to know about laboratory tests -7-
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The “Buts”
You are healthy in one Lab
– but sick in another
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25 hydroxyvitamin D
“Vitamin D assays yield markedly differing results; whether an
individual is found to have low or normal vitamin D status is a
function of the laboratory used. If the medical community is to
make progress in correcting widespread hypovitaminosis D,
vitamin D measurement must be standardized”
J Clin Endocrinol Metab
Binkley N, et al. Assay variation confounds the diagnosis of hypovitaminosis
D: A call for standardization. J Clin Endocrinol Metab 2004;89:3152–7.
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Parathyroid hormone
“It appears unethical that all the companies making different
PTH assays could not meet and decide how to standardize
and calibrate a consistent circulating PTH measurement. Many
physicians are making huge efforts to keep their patients
within the target values recommended by the NKF/K-DOQI;
however, most of them are misinformed by their PTH
measurement”.
Kidney Int
Torres PU. The need for reliable serum parathyroid hormone measurements.
Kidney Int 2006;70:240-3.
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Testosterone
Widely used assay methods to measure serum testosterone
suffer from a lack of accuracy and sensitivity, making it
difficult for physicians to appropriately diagnose and treat
androgen-related disorders in women, children, and men. The
February 2007 issue of the Journal of Clinical Endocrinology &
Metabolism calls for standardizing the methods by which
these assays are validated.
J Clin Endocrinol Metab
http://www.endo-society.org/media/press/2007/
EndocrinePositionStatementCallsStandardizedTestosteroneAssays.cfm
http://www.cdc.gov/nceh/dls/hormone_standardization.htm
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Standardization
Tip of the iceberg!
25 hydroxyvitamin D
Parathyroid hormone
Testosterone
General problem
Steroid hormones
Thyroid hormones
Protein hormones
Glyoprotein hormones
Cardiac markers
Tumor markers
New markers (Cytokines, Growth factors)
>And so much more
Nearly did'nt dare to come out again!
No Titanic around?
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Reference intervals
Serum sodium reference interval
"Variation in reference intervals was not related
to analytical platforms".
"The major reason for variation was simply historical, with no
scientific foundation".
>Not restricted to the UK!
http://www.pathologyharmony.co.uk/graphics/Pathology%20Harmony%20N
ewsletter%20July%202008.pdf
Serum magnesium reference interval
Dewitte K. In search of the reference interval of serum
magnesium – The last case of Hercule Poirot [in Dutch].
BVLT Tijdschrift 2000;27:169-73.
>Origin of the Tietz reference interval
could not been traced.
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I type ...
... what science is that!?
It was'nt me who
said it.
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The next visit
Standardization & Traceability
The solution
That makes
me curious!
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