Hi Steven,
This Australian study of falsely raised cardiac troponins has interestingly used Greiner tubes but didn't blame them for the falsely elevated results.
http://www.clinchem.org/content/57/5/710.full.pdf+html
BW
Mohammad
<b>Dr. M A Al-Jubouri, MB ChB, MSc, EurClinChem, FRCP Edin, FRCPath
Consultant Chemical Pathologist</b>
--------------------------------------------
On Wed, 11/13/13, Steven John Mccann <[log in to unmask]> wrote:
Subject: Siemens troponin I ultra assay serum v plasma and ?flyers
To: [log in to unmask]
Date: Wednesday, November 13, 2013, 3:59 PM
Hi there,
Currently we use serum
(greiner tubes) for routine work however it appears that
around 1 in 300 of our positive TnI results on repeating on
the same specimen come back negative. We use a cut-off of
20ng/L and currently repeat all samples
above this to confirm the result. Negatives go straight
out. The change noticed is beyond the 20ish% CV of the assay
such that on some occasions results have been > 100ng/L
but on repeat are <20ng/L. The samples are not spun
prior to repeat testing. The cause
is proposed to be microclots which affect us due to our
rapid analysis.
Do other users delay
analysis to allow for complete clotting or use plasma
instead? Do any other labs repeat positive TnI on the same
sample if serum or plasma is used to check for
‘flyers’?
Thank you for any
replies.
Steven
Steven
McCann FRCPath EurClinChem
Consultant
Clinical Biochemist and Clinical Biochemistry
Lead
Stepping
Hill Hospital
Poplar
Grove
Stockport
NHS Foundation Trust
SK2
7JE
Tel No 0161
419 5619
Fax No 0161
419 5668
www.stockport.nhs.uk
www.nhslabmedservices.co.uk
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