Hi
We are continually plagued by a handfull of (pseudo) high serum
potassiums which on checking 2-3 days later are normal in both serum
and plasma. All the usual suspects have drawn a blank and I was
considering putting a centrifuge in the GP's surgery in an attempt to
pin down some sort of transport/storage effect when I came across a
Clin Chem technical brief (vol. 45(7)1999 page 1091) which would
appear to provide a reasonable explanation. They observe that "the
extent of K release during clotting or during delays in separation
.....means that a true K of 4.2 may in fact range from 3.8 to 5.4
mmol/L. This variation is unpredictable, unrelated to concentration
and additive to inherent biological variation". The bottom line is if
you are serious about potassium use plasma!
Peter Auld
Consultant Scientist
Antrim Hospital
______________________________ Reply Separator _________________________________
Subject: Re: transport, and GP patients with spuriously high serum...
Author: "Dr. David Acheampong-Mensah" <[log in to unmask]> at
UNITED_HOSPITALS
Date: 1/26/02 1:36 AM
Subject:
Re: transport, and GP patients with spuriously high serum K's
---------------------------------
Mike,
I would appreciate a reference (study) supporting your observation.
Thanks
David A. Mensah, PhD, FACB, MT(ASCP)
Clinical Biochemist & Director of Laboratory Services
Providence St. Peter Hospital
Olympia, WA, 985506
USA
>From: Mike Collins <[log in to unmask]>
>Reply-To: Mike Collins <[log in to unmask]>
>To: [log in to unmask]
>Subject: Re: transport, and GP patients with spuriously high
serum K's
>Date: Fri, 25 Jan 2002 17:42:20 -0000
>
>Les Culank wrote:
> > Have you evidence-based standards for GP specimen
>transport, for
> > example specifying limits of time, temperature, maybe other > >
relevant factors, to avoid spurious elevation of measured
>serum
> > potassium?
>
>I don't think this you can give a definite time for potassium
>since the leakage of K+ from the cells begins when the >glucose
levels drop too low for the sodium pump to operate. A >sample with
an initial glucose of 25 mmol/L will be OK for >potassium
measurement after 24 hours at room temperature.
>
>Mike Collins
>
>
>
> >
> > Many thanks,
> >
> > Les
> >
> > -- Dr Les Culank,
> > Consultant Chemical Pathologist, Addenbrooke's
>
>
>Mike Collins MLSO3
>Clinical Biochemistry & Immunology
>The General Infirmary at Leeds,
>Old Medical School, Thoresby Place
>Leeds LS1 3EX, UK
>[log in to unmask]
>[log in to unmask]
>44 (0) 113 392 2915
>http://www.leedsteachinghospitals.com
>The opinions expressed here are my own.
>My colleagues and employers may not agree with them.
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