Effect of N-acetylcysteine on the accuracy of the prothrombin time assay of plasma coagulation factor II plus VII plus X activity in subjects infused with the drug. Influence of time and temperature

S. Thorsen; A. Teisner; S.A. Jensen; M. Philips; K. Dalhoff; F. Bendtsen

Effect of N-acetylcysteine on the accuracy of the prothrombin time assay of plasma coagulation factor II plus VII plus X activity in subjects infused with the drug. Influence of time and temperature

S. Thorsen, A. Teisner, S.A. Jensen, M. Philips, K. Dalhoff, F. Bendtsen

9 Citations (Scopus)

Abstract

Objectives: The prothrombin time (PT) assay of factor II+VII+X activity is an important predictor of liver damage in paracetamol poisoned patients. It complicates interpretation of results that the antidote, acetylcysteine (NAC) depresses this activity. The aim was to investigate if NAC influences the accuracy of the plasma PT assay. Materials and methods: The accuracy of Nycotest (R) PT was studied using plasma added NAC in vitro and plasma from subjects infused with NAC. The latter results were compared with those obtained by analysis of PT by CoaguChek (R) S. Results: Therapeutic NAC concentrations added to plasma in vitro decreased factor II+VII+X activity at 37 degrees C in a time-dependent manner. This effect was quenched at temperatures 24 degrees C. Activity lost at 37 degrees C could partly be recovered by subsequent incubation at 5 or 20 degrees C. Incubation at 37 degrees C prior to assay led to a significant additional depression of factor II+VII+X activity in plasma from subjects infused with NAC during the first 3h of infusion indicating that it contained reactive NAC. The risk that this NAC interfered with the accuracy of the PT assay was considered minimal with samples stored below 24 degrees C. This was supported by similarity of results obtained by analysis of appropriately stored plasma and simultaneously drawn blood by CoaguChek (R) S. Conclusions: Residual reactive NAC does not interfere with the accuracy of the PT assay of plasma stored below 24 degrees C, but NAC-induced loss in activity at 37 degrees C may be partly recovered during subsequent storage below 24 degrees C
Udgivelsesdato: 2009

Original language	Danish
Journal	Scandinavian Journal of Clinical & Laboratory Investigation
Volume	69
Issue number	6
Pages (from-to)	643-650
Number of pages	7
ISSN	0036-5513
Publication status	Published - 2009

Cite this

Effect of N-acetylcysteine on the accuracy of the prothrombin time assay of plasma coagulation factor II plus VII plus X activity in subjects infused with the drug. Influence of time and temperature. / Thorsen, S.; Teisner, A.; Jensen, S.A. et al.

In: Scandinavian Journal of Clinical & Laboratory Investigation, Vol. 69, No. 6, 2009, p. 643-650.

Research output: Contribution to journal › Journal article › Research › peer-review

Thorsen, S, Teisner, A, Jensen, SA, Philips, M, Dalhoff, K & Bendtsen, F 2009, 'Effect of N-acetylcysteine on the accuracy of the prothrombin time assay of plasma coagulation factor II plus VII plus X activity in subjects infused with the drug. Influence of time and temperature', Scandinavian Journal of Clinical & Laboratory Investigation, vol. 69, no. 6, pp. 643-650.

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title = "Effect of N-acetylcysteine on the accuracy of the prothrombin time assay of plasma coagulation factor II plus VII plus X activity in subjects infused with the drug. Influence of time and temperature",

abstract = "Objectives: The prothrombin time (PT) assay of factor II+VII+X activity is an important predictor of liver damage in paracetamol poisoned patients. It complicates interpretation of results that the antidote, acetylcysteine (NAC) depresses this activity. The aim was to investigate if NAC influences the accuracy of the plasma PT assay. Materials and methods: The accuracy of Nycotest (R) PT was studied using plasma added NAC in vitro and plasma from subjects infused with NAC. The latter results were compared with those obtained by analysis of PT by CoaguChek (R) S. Results: Therapeutic NAC concentrations added to plasma in vitro decreased factor II+VII+X activity at 37 degrees C in a time-dependent manner. This effect was quenched at temperatures 24 degrees C. Activity lost at 37 degrees C could partly be recovered by subsequent incubation at 5 or 20 degrees C. Incubation at 37 degrees C prior to assay led to a significant additional depression of factor II+VII+X activity in plasma from subjects infused with NAC during the first 3h of infusion indicating that it contained reactive NAC. The risk that this NAC interfered with the accuracy of the PT assay was considered minimal with samples stored below 24 degrees C. This was supported by similarity of results obtained by analysis of appropriately stored plasma and simultaneously drawn blood by CoaguChek (R) S. Conclusions: Residual reactive NAC does not interfere with the accuracy of the PT assay of plasma stored below 24 degrees C, but NAC-induced loss in activity at 37 degrees C may be partly recovered during subsequent storage below 24 degrees C Udgivelsesdato: 2009",

author = "S. Thorsen and A. Teisner and S.A. Jensen and M. Philips and K. Dalhoff and F. Bendtsen",

note = "Times Cited: 0ArticleEnglishBendtsen, FHvidovre Univ Hosp, Dept Gastroenterol 439, Kettegard Alle 30, DK-2650 Hvidovre, DenmarkCited References Count: 28494IUTAYLOR & FRANCIS ASKARL JOHANS GATE 5, NO-0154 OSLO, NORWAYOSLO",

year = "2009",

language = "Dansk",

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T1 - Effect of N-acetylcysteine on the accuracy of the prothrombin time assay of plasma coagulation factor II plus VII plus X activity in subjects infused with the drug. Influence of time and temperature

AU - Thorsen, S.

AU - Teisner, A.

AU - Jensen, S.A.

AU - Philips, M.

AU - Dalhoff, K.

AU - Bendtsen, F.

N1 - Times Cited: 0ArticleEnglishBendtsen, FHvidovre Univ Hosp, Dept Gastroenterol 439, Kettegard Alle 30, DK-2650 Hvidovre, DenmarkCited References Count: 28494IUTAYLOR & FRANCIS ASKARL JOHANS GATE 5, NO-0154 OSLO, NORWAYOSLO

PY - 2009

Y1 - 2009

N2 - Objectives: The prothrombin time (PT) assay of factor II+VII+X activity is an important predictor of liver damage in paracetamol poisoned patients. It complicates interpretation of results that the antidote, acetylcysteine (NAC) depresses this activity. The aim was to investigate if NAC influences the accuracy of the plasma PT assay. Materials and methods: The accuracy of Nycotest (R) PT was studied using plasma added NAC in vitro and plasma from subjects infused with NAC. The latter results were compared with those obtained by analysis of PT by CoaguChek (R) S. Results: Therapeutic NAC concentrations added to plasma in vitro decreased factor II+VII+X activity at 37 degrees C in a time-dependent manner. This effect was quenched at temperatures 24 degrees C. Activity lost at 37 degrees C could partly be recovered by subsequent incubation at 5 or 20 degrees C. Incubation at 37 degrees C prior to assay led to a significant additional depression of factor II+VII+X activity in plasma from subjects infused with NAC during the first 3h of infusion indicating that it contained reactive NAC. The risk that this NAC interfered with the accuracy of the PT assay was considered minimal with samples stored below 24 degrees C. This was supported by similarity of results obtained by analysis of appropriately stored plasma and simultaneously drawn blood by CoaguChek (R) S. Conclusions: Residual reactive NAC does not interfere with the accuracy of the PT assay of plasma stored below 24 degrees C, but NAC-induced loss in activity at 37 degrees C may be partly recovered during subsequent storage below 24 degrees C Udgivelsesdato: 2009

AB - Objectives: The prothrombin time (PT) assay of factor II+VII+X activity is an important predictor of liver damage in paracetamol poisoned patients. It complicates interpretation of results that the antidote, acetylcysteine (NAC) depresses this activity. The aim was to investigate if NAC influences the accuracy of the plasma PT assay. Materials and methods: The accuracy of Nycotest (R) PT was studied using plasma added NAC in vitro and plasma from subjects infused with NAC. The latter results were compared with those obtained by analysis of PT by CoaguChek (R) S. Results: Therapeutic NAC concentrations added to plasma in vitro decreased factor II+VII+X activity at 37 degrees C in a time-dependent manner. This effect was quenched at temperatures 24 degrees C. Activity lost at 37 degrees C could partly be recovered by subsequent incubation at 5 or 20 degrees C. Incubation at 37 degrees C prior to assay led to a significant additional depression of factor II+VII+X activity in plasma from subjects infused with NAC during the first 3h of infusion indicating that it contained reactive NAC. The risk that this NAC interfered with the accuracy of the PT assay was considered minimal with samples stored below 24 degrees C. This was supported by similarity of results obtained by analysis of appropriately stored plasma and simultaneously drawn blood by CoaguChek (R) S. Conclusions: Residual reactive NAC does not interfere with the accuracy of the PT assay of plasma stored below 24 degrees C, but NAC-induced loss in activity at 37 degrees C may be partly recovered during subsequent storage below 24 degrees C Udgivelsesdato: 2009

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JO - Scandinavian Journal of Clinical & Laboratory Investigation

JF - Scandinavian Journal of Clinical & Laboratory Investigation

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ER -