False-positive troponin I measured with the Abbott AxSYM attributed to fibrin interference

Steven (Steve) Kazmierczak, Harmanjatinder Sekhon, Christopher Richards

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Background: Serum is often used for the measurement of cardiac troponin I (cTnI). Previous reports suggest that fibrin present in serum samples collected for cTnI analysis may interfere with measurement of this marker. We investigated the incidence and magnitude of fibrin interference in serum specimens submitted for cTnI measurement using the AxSYM analyzer by performing duplicate analysis of all specimens with increased cTnI results. Methods: Over a 4-month period, we analyzed 3692 specimens for cTnI with the Abbott AxSYM. Of these, 307 (8.3%) showed increased cTnI. A threshold of three times the precision of the method (15%) was used to judge discrepancies between duplicate analyses of specimens; all specimens being recentrifuged between the initial and repeat cTnI analyses. Results: Of 307 patient specimens with elevated cTnI concentrations, 24 (7.8%) demonstrated differences of greater than 45% between duplicate analyses. Concentrations of cTnI obtained on initial analysis of these 24 specimens ranged from 2.4 to 24.0 μg/l. Repeat analysis showed the repeat values for 20 (83%) to be within the normal reference interval, with 16 (67%) showing concentrations of less than 0.3 μg/l. Conclusions: Our finding indicates that interference should be highly suspected in serum specimens where the initially measured cTnI concentrations is in the range of 2.0-25.0 μg/l when using the Abbott AxSYM. The finding of no interference in specimens with measured troponin concentration greater than 25.0 μg/l suggests that the interference effect of fibrin is generally not sufficient to cause spurious elevations of cTnI into this range. In addition, since switching to plasma as the specimen of choice for the AxSYM, we have not observed any discrepant cTnI results following duplicate analysis of over 200 patient samples with initial measured cTnI concentrations of 2.0 μg/l or greater.

Original languageEnglish (US)
Pages (from-to)27-31
Number of pages5
JournalInternational Journal of Cardiology
Volume101
Issue number1
DOIs
StatePublished - May 11 2005

Fingerprint

Troponin I
Fibrin
Serum
Troponin

Keywords

  • False-positive test results
  • Test interference
  • Troponin I

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Cite this

False-positive troponin I measured with the Abbott AxSYM attributed to fibrin interference. / Kazmierczak, Steven (Steve); Sekhon, Harmanjatinder; Richards, Christopher.

In: International Journal of Cardiology, Vol. 101, No. 1, 11.05.2005, p. 27-31.

Research output: Contribution to journalArticle

@article{9bb97e196498493c9c5f3557eaa5d212,
title = "False-positive troponin I measured with the Abbott AxSYM attributed to fibrin interference",
abstract = "Background: Serum is often used for the measurement of cardiac troponin I (cTnI). Previous reports suggest that fibrin present in serum samples collected for cTnI analysis may interfere with measurement of this marker. We investigated the incidence and magnitude of fibrin interference in serum specimens submitted for cTnI measurement using the AxSYM analyzer by performing duplicate analysis of all specimens with increased cTnI results. Methods: Over a 4-month period, we analyzed 3692 specimens for cTnI with the Abbott AxSYM. Of these, 307 (8.3{\%}) showed increased cTnI. A threshold of three times the precision of the method (15{\%}) was used to judge discrepancies between duplicate analyses of specimens; all specimens being recentrifuged between the initial and repeat cTnI analyses. Results: Of 307 patient specimens with elevated cTnI concentrations, 24 (7.8{\%}) demonstrated differences of greater than 45{\%} between duplicate analyses. Concentrations of cTnI obtained on initial analysis of these 24 specimens ranged from 2.4 to 24.0 μg/l. Repeat analysis showed the repeat values for 20 (83{\%}) to be within the normal reference interval, with 16 (67{\%}) showing concentrations of less than 0.3 μg/l. Conclusions: Our finding indicates that interference should be highly suspected in serum specimens where the initially measured cTnI concentrations is in the range of 2.0-25.0 μg/l when using the Abbott AxSYM. The finding of no interference in specimens with measured troponin concentration greater than 25.0 μg/l suggests that the interference effect of fibrin is generally not sufficient to cause spurious elevations of cTnI into this range. In addition, since switching to plasma as the specimen of choice for the AxSYM, we have not observed any discrepant cTnI results following duplicate analysis of over 200 patient samples with initial measured cTnI concentrations of 2.0 μg/l or greater.",
keywords = "False-positive test results, Test interference, Troponin I",
author = "Kazmierczak, {Steven (Steve)} and Harmanjatinder Sekhon and Christopher Richards",
year = "2005",
month = "5",
day = "11",
doi = "10.1016/j.ijcard.2004.03.008",
language = "English (US)",
volume = "101",
pages = "27--31",
journal = "International Journal of Cardiology",
issn = "0167-5273",
publisher = "Elsevier Ireland Ltd",
number = "1",

}

TY - JOUR

T1 - False-positive troponin I measured with the Abbott AxSYM attributed to fibrin interference

AU - Kazmierczak, Steven (Steve)

AU - Sekhon, Harmanjatinder

AU - Richards, Christopher

PY - 2005/5/11

Y1 - 2005/5/11

N2 - Background: Serum is often used for the measurement of cardiac troponin I (cTnI). Previous reports suggest that fibrin present in serum samples collected for cTnI analysis may interfere with measurement of this marker. We investigated the incidence and magnitude of fibrin interference in serum specimens submitted for cTnI measurement using the AxSYM analyzer by performing duplicate analysis of all specimens with increased cTnI results. Methods: Over a 4-month period, we analyzed 3692 specimens for cTnI with the Abbott AxSYM. Of these, 307 (8.3%) showed increased cTnI. A threshold of three times the precision of the method (15%) was used to judge discrepancies between duplicate analyses of specimens; all specimens being recentrifuged between the initial and repeat cTnI analyses. Results: Of 307 patient specimens with elevated cTnI concentrations, 24 (7.8%) demonstrated differences of greater than 45% between duplicate analyses. Concentrations of cTnI obtained on initial analysis of these 24 specimens ranged from 2.4 to 24.0 μg/l. Repeat analysis showed the repeat values for 20 (83%) to be within the normal reference interval, with 16 (67%) showing concentrations of less than 0.3 μg/l. Conclusions: Our finding indicates that interference should be highly suspected in serum specimens where the initially measured cTnI concentrations is in the range of 2.0-25.0 μg/l when using the Abbott AxSYM. The finding of no interference in specimens with measured troponin concentration greater than 25.0 μg/l suggests that the interference effect of fibrin is generally not sufficient to cause spurious elevations of cTnI into this range. In addition, since switching to plasma as the specimen of choice for the AxSYM, we have not observed any discrepant cTnI results following duplicate analysis of over 200 patient samples with initial measured cTnI concentrations of 2.0 μg/l or greater.

AB - Background: Serum is often used for the measurement of cardiac troponin I (cTnI). Previous reports suggest that fibrin present in serum samples collected for cTnI analysis may interfere with measurement of this marker. We investigated the incidence and magnitude of fibrin interference in serum specimens submitted for cTnI measurement using the AxSYM analyzer by performing duplicate analysis of all specimens with increased cTnI results. Methods: Over a 4-month period, we analyzed 3692 specimens for cTnI with the Abbott AxSYM. Of these, 307 (8.3%) showed increased cTnI. A threshold of three times the precision of the method (15%) was used to judge discrepancies between duplicate analyses of specimens; all specimens being recentrifuged between the initial and repeat cTnI analyses. Results: Of 307 patient specimens with elevated cTnI concentrations, 24 (7.8%) demonstrated differences of greater than 45% between duplicate analyses. Concentrations of cTnI obtained on initial analysis of these 24 specimens ranged from 2.4 to 24.0 μg/l. Repeat analysis showed the repeat values for 20 (83%) to be within the normal reference interval, with 16 (67%) showing concentrations of less than 0.3 μg/l. Conclusions: Our finding indicates that interference should be highly suspected in serum specimens where the initially measured cTnI concentrations is in the range of 2.0-25.0 μg/l when using the Abbott AxSYM. The finding of no interference in specimens with measured troponin concentration greater than 25.0 μg/l suggests that the interference effect of fibrin is generally not sufficient to cause spurious elevations of cTnI into this range. In addition, since switching to plasma as the specimen of choice for the AxSYM, we have not observed any discrepant cTnI results following duplicate analysis of over 200 patient samples with initial measured cTnI concentrations of 2.0 μg/l or greater.

KW - False-positive test results

KW - Test interference

KW - Troponin I

UR - http://www.scopus.com/inward/record.url?scp=18144409063&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=18144409063&partnerID=8YFLogxK

U2 - 10.1016/j.ijcard.2004.03.008

DO - 10.1016/j.ijcard.2004.03.008

M3 - Article

VL - 101

SP - 27

EP - 31

JO - International Journal of Cardiology

JF - International Journal of Cardiology

SN - 0167-5273

IS - 1

ER -