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- Hillarp, Andreas, et al.
(författare)
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Local INR calibration of the Owren type prothrombin assay greatly improves the intra- and interlaboratory variation
- 2004
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Ingår i: Thrombosis and Haemostasis. - 0340-6245 .- 2567-689X. ; 91:2, s. 300-307
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Tidskriftsartikel (refereegranskat)abstract
- In 1999, a simplified procedure for calibration of the Owren prothrombin time (Owren PT) assay was introduced by a working group of the organisation for national quality assurance in laboratory medicine in Sweden. The new protocol allowed local calibration by means of only two lyophilised national plasma calibrators and expression of results as an international normalized ratio (INR). This is our report of a three-year follow-up involving the analysis of data from all laboratories, in hospitals (n=88 in 2002) and primary health care units (n=246 in 2002) that perform the Owren PT assay in Sweden. The interlaboratory variation was significantly improved after the introduction of the new calibration procedure. For the larger hospital-based laboratories, the mean coefficient of variation (CV) was reduced from 7.9% to 5.2% (p<0.0001) when analysing test materials with INR range 2-4. In the higher INR range (>4), the CV was reduced even further, from 10.4% to 6.8% (p<0.0001). The corresponding results from smaller laboratories in the primary health care units showed a similar decrease in CV from 8.2% to 5.7% in the INR range 2-4 (p<0.0001). At the INR range >4, the CV was reduced from 9.5% to 7.8%. The intralaboratory variation was also improved for both types of laboratory categories. This study shows an improved precision, with CV less than 6% at the therapeutic INR range, for both hospital-based laboratories and smaller laboratories in the primary health care system. The results indicate that the Owren PT assay is well suited for local INR calibration employing only two calibrant plasmas in a simplified procedure.
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| 4. |
- Hillarp, Andreas, et al.
(författare)
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Mer samstämmiga laboratorieresultat efter övergången till INR. Skillnaderna mellan sjukhus- och primärvårdslaboratorier utjämnade
- 2002
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Ingår i: Läkartidningen. - 0023-7205. ; 99:50, s. 70-5073
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Tidskriftsartikel (refereegranskat)abstract
- In 1999 a new and simplified procedure for calibration of the Owren prothrombin time (Owren PT) assay was introduced in Sweden by the national external quality assessment scheme (Equalis). The new protocol allowed local calibration by means of lyophilised national plasma calibrators and expression of results as an international normalised ratio (INR). A two-year follow-up involving analysis of data from all laboratories that have returned results to Equalis is reported. There was a significant reduction in both between-laboratory and within-laboratory variation after the introduction of the new calibration procedure. For the larger hospital laboratories analysing external controls with INR>2, the mean coefficient of variation (CV) was reduced from 9.1% to 5.6% (P<0.0001). The corresponding results from smaller laboratories in the primary health care units showed a similar decrease in CV from 8.8% to 6.3% (P<0.0001). This study shows that the Owren PT assay is well suited for INR calibration employing calibrant plasmas.
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| 6. |
- Sjöblom, Lars, et al.
(författare)
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Management and prognostic features of intracerebral hemorrhage during anticoagulant therapy - A Swedisih multicenter study
- 2001
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Ingår i: Stroke: a journal of cerebral circulation. - : Ovid Technologies (Wolters Kluwer Health). - 1524-4628 .- 0039-2499. ; 32:11, s. 2567-2574
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose-Patients treated with oral anticoagulants (ACs) have an increased risk of intracerebral hemorrhage (ICH), which is more often fatal than spontaneous ICH. Options to reverse the AC effect include intravenous administration of vitamin K, plasma, and coagulation factor concentrate. However, the optimal management of AC-related ICH has not been determined in any randomized trial. In this study, the present management of AC-related ICH was surveyed, and determinants of survival were assessed. Methods-We retrospectively reviewed the medical records of all AC-related ICHs at 10 Swedish hospitals during a 4-year period, 1993 to 1996. Survival status after the ICH was determined from the Swedish National population register. Results-We identified 151 patients with AC-related ICH. Death rates were 53.6% at 30 days, 63.6% at 6 months, and 77.5% at follow-up (mean 3.5 years). The case fatality ratio at 30 days was 96% among patients unconscious on admission (n=27), 80% among patients who became unconscious before active treatment was started (n=15), 55% among patients in whom no special action was taken except withdrawal of AC treatment (n=42), and 28% among patients given active anti-coumarin treatment while they were still conscious (n=64). The case fatality, ratio at 30 days was 11% in the group treated with plasma (n = 18), 30% in the group treated with vitamin K (n = 23), and 39% in the group treated with coagulation factor concentrate (n=23). Within the first 24 to 48 hours after admission, 47% of the patients deteriorated. Choice of therapy to reverse the AC effect differed substantially between the hospitals (P <0.0001), as did the time interval from symptom onset to start of treatment. Multiple logistic regression analysis showed only 2 factors (intraventricular extension of bleeding and ICH volume) that were independently related to case fatality at both 30 days and 6 months. The results were similar when the analysis was restricted to patients who were conscious on admission. Conclusions-In AC-related ICH, a progressive, neurological deterioration during the first 24 to 48 hours after admission is frequent, and the mortality is high. Choice of therapy to reverse the AC effect differed considerably between the hospitals. There was no evidence that any treatment strategy was superior to the others. A randomized controlled trial is needed to determine the best choice of treatment.
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