Dear Elliott and Co,
We too use Elecsys trop T (sparingly) and have also been looking at a
similarly sparse CCU population in the last 10 days. Our results on litium
hep plasma (Greiner) v serum are as follows to date :
Plasma Serum
<0.01 <0.01
0.04 0.04
0.14 0.13
<0.01 <0.01
0.04 0.04
0.05 0.04
0.02 0.02
<0.01 <0.01
0.04 <0.01
20.1 19.9
0.02 0.02
0.02 0.02
The data Roche supplied originally from a (?) German or Swedish hospital
showed an effect on trop T which increased with increasing heparin
concentrations in the sample tube. There was little effect below a heparin
concentration of 50 IU/ml. According to our information, the Greiner tubes
have 56 IU/ 4 ml blood, i.e.14 IU/ml IF the bottle has 4 ml blood.
The few pairs of results shown above seem to bear this out, although this is
scanty data and mostly at the low end. We will continue to collect data, but
if other users have similar data, perhaps we could pool it and save some
labour ?
Best wishes
Philip Hyde
Pilgrim Hospital
Boston (UK)
>From: Simpson Elliott <[log in to unmask]>
>Reply-To: Simpson Elliott <[log in to unmask]>
>To: "'p=NHS NATIONAL INT;a=NHS;c=GB;dda:RFC-822=jjmill01(a)gwise.loui"
><[log in to unmask]>
>CC: "[log in to unmask]"
><[log in to unmask]>
>Subject: RE: Heparin & Troponin
>Date: Wed, 12 Jul 2000 09:54:35 +0100
>
>We use the ROCHE ELECSYS method for TnT.
>
>We asked our phlebotomists to collect a heparin PST (Vacutainer) along with
>the usual SST tube from the patients in our CCU for a week (and our thanks
>go to the medical staff for allowing this access to their patients). The
>results in the table below show that we find lower levels in plasma than in
>sera. Sera which gave a positive result (column a) were repeated (column
>b)
>along with the plasma (column c) to eliminate any time delay effect.
>Although the differences are less than the 15% quoted below, they are in
>broad agreement with the finding that plasma TnT levels are lower than
>serum
>and will continue to recommend that only serum be used.
>
>I'm not certain if it would stand up to a controlled trial, but as is so
>often the case, showing an interest in any condition seems to have the
>immediate effect of reducing the frequency of the condition. We've never
>had a week with so few raised TnT levels from our CCU.
>
>
>Initial Serum TnT result Repeat serum TnT Plasma TnT % difference
> 3.20 2.89
>9.7
> 1.62 1.62 1.48
>8.6
> 1.27 1.27 1.19
>6.3
> 0.014 0.015 <0.01
>
> 0.788 0.801 0.769
>4.0
> 0.037 0.039 0.037
>0.5
>
>
>JE Hogg, N Jiwani, E Simpson
>Monklands Hospital,
>Airdrie, UK
>
>-----Original Message-----
>From: p=NHS NATIONAL
>INT;a=NHS;c=GB;dda:RFC-822=acb-clin-chem-gen-request(a)mailbase.ac.uk;
>Sent: 22 June 2000 21:05
>To: p=NHS NATIONAL
>INT;a=NHS;c=GB;dda:RFC-822=MEDLAB-L(a)LISTSERV.ACSU.BUFFALO.EDU;; p=NHS
>NATIONAL INT;a=NHS;c=GB;dda:RFC-822=acb-clin-chem-gen(a)mailbase.ac.uk;
>Subject: Heparin & Troponin
>
>
>The paper by Gerhardt, et al. in this month's Clinical Chemistry (46:817)
>reports on the false decreases in TnT (Elecsys) and TnI (Immulite) using
>heparin plasma compared to serum (average about 15% but up to 30% or so in
>some samples). When introducing TnI on Stratus about 8 years ago and when
>switching to TnI on AxSYM a few years ago, we found no significant
>difference between serum and heparin plasma (although we may not have
>looked
>as carefully as in this paper). Does anyone have other data that conflicts
>with this report of false decreases in TnI or TnT on heparinized plasma
>samples compared to serum?
>
>James J Miller, Ph.D., DABCC
>Associate Professor
>Dept. of Pathology & Laboratory Medicine
>University of Louisville
>Louisville, KY 40292
>
>502-852-1179
>
>
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