José Navarro-Alvárez wrote:

>You are right Dr Ohman. The ionised calcium is a useful and simple test.
>
>I think
>albumin-corrected calcium during pregnancy is not a good idea, since the
>
>albumin
>is often altered during pregnancy and the corrected calcium formula may
>be not a
>appropriate.

Glad to see that you agree! I have spent years in investigating the importance
of this test and I cannot understand why most laboratories around the world
continue to do total and/or albumin corrected serum calcium. The value of
ionized calcium is well-documented and nobody should ever hesitate to do
this test whenever an error in calcium metabolism is suspected.

Several authors have compared ionized calcium with total or albumin-correted
calcium and all studies undoubtly speaks in favour of the former.

Isn't this only one example where we, clinical chemists, reject well-documented
tests in favour of traditional tests, mainly because the better method may
cost a few Euro more?

For all diagnostic tests you must consider not only the cost of the test, but
its importance for the medical decision! Laboroatory tests are very cheap
compared with both other diagnostic methods (e.g. tomographic methods), and
still cheaper compared with the total cost of incorrect diagnostics.

We, clinical chemists, must consider that we are selling INFORMATION to
the clinicians. The more specific this information is, the more valuable
for the clinician, and the higher price can be payed for the information!

Look at your library: You can see several shelf-meters are occupied by
numerous volumes of Clin Chem, Ann Clin Biochem, Scand J Clin Lab Invest, 
Clin Chim Acta etc. Each of those articles have costed years of efforts for the
authors, referees and editors. All this effort is worth a better fate than 
quietly residing in the libraries!

Ionized calcium is only one example where conventional, fuzzy methods are
used instead of well-documented specific methods. Another example is CSF
analysis in multiple sclerosis, which is another field which I have studied 
exhaustively, and which I made my PhD on.

A few years ago all top experts in this field publised a consensus work
(Anderson M et al: Cerebrospinal fluid in the diagnosis of multiple sclerosis:
a consensus report. J Neurol Neurosurg Psych 1994;57:897-902) clearly
stating that isofocusing of CSF using a specific IgG method is the most 
significant method for this diagnosis. Nevertheless, most laboratories continue
to use qualitatively inferior methods, often without the use of external
controls!

Therefore many false positive and/or negative results are reported to
the neurologists. Consequently, the neurologists doubt the value of the
method and instead they use MRI, which costs about 10 times as much as 
a high-qualtiative isofocusing method! Yes, MRI yields a better information
than the "bad" laboratory methods but, if done according to the consensus
work, the CSF method is superior.

We, clinical chemists, must realize the importance of the technique for the
diagnostic value, but in most hospitals the leadership of the laboratory 
lazely consider that the neurologists prefer MRI before CSF analysis.
The role of the neurologist is to serve the patient, not telling us which
methods shall be used in the laboratory!

If we, clinical chemists, don't realize the importance of the appropriate 
technique, who shall do it?

I have mentioned two methods in which I have participated in evaluating the
importance of the technique on the diagnostic value. I am convinced that
most of you participating in this discussion group have similar experiences.

So, why is this enormous knowledge not used? Why do we continue using
conventional but inferior methods instead of well-documented but rarely used 
methods? Why do we prefer using standard methods set up locally instead
of sending the samples to specialized laboratories where they can be
analyzed by 
specific and more informative methods?

-----------------------------------------------------
From:                Mr Sten Öhman, PhD
Postal address:      p.o. Box 133, S-590 70 Ljungsbro, Sweden
E-Mail address:      [log in to unmask]
Phone:               int: +46 13 219020, nat: 013-219020
Fax:                 int: +46 13 219021, nat: 013-219021
Personal home page:  http://hem1.passagen.se/stoh7971/
Company home page:   http://www.elfinilab.se/
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