Comparison of the Sensitivity of Commercial APTT Reagents in the Detection of Mild Coagulopathies

Marlar, Richard A.; Bauer, Patricia J.; Endres-Brooks, Janet; Montgomery, Robert R.; Miller, Christine; Schanen, Michelle M.

doi:10.1093/ajcp/82.4.436

Cited by 27 publications

(21 citation statements)

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“…Variable responsiveness of commercial reagents to hypocoagulability is already known. 18,19 A similar variability in response to hypercoagulability can be anticipated, but comparative observations are lacking and confirmation of these findings with other reagents is warranted.…”

Section: Discussionmentioning

confidence: 91%

A shortened activated partial thromboplastin time is associated with the risk of venous thromboembolism

Tripodi

Chantarangkul

Martinelli

et al. 2004

Blood

181

128

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Hypercoagulability due to high coagulation factors XI, VIII, IX, II, and fibrinogen is recognized as a risk factor of venous thromboembolism (VTE). These factors are cumulatively explored by the activated partial thromboplastin time (APTT). To test the hypothesis that a short APTT increases the risk of VTE, a case-control study was carried out in 605 patients referred for thrombophilia testing after documented VTE and in 1290 controls. Median APTT ratio (coagulation time of test-to-reference plasma) values were 0.97 (range: 0.75-1.41) for patients and 1.00 (range: 0.72-1.33) for controls (P < .001). In patients who had an APTT ratio smaller than the fifth percentile of the distribution in controls, the odds ratio (OR) for VTE was 2.4 (95% confidence interval [CI]: 1.7-3.6) and was independent of inherited thrombophilic abnormalities. Further statistical analyses in 193 patients and 259 controls for whom factor VIII (FVIII) levels were available showed a decrease of the OR from 2.7 (95% CI: 1.4-5.3) to 2.1 (95% CI: 1.0-4.2), indicating that the risk was only partially mediated by high FVIII levels. In conclusion, hypercoagulability detected by a shortened APTT is independently associated with VTE. This inexpensive and simple test should be considered in the evaluation of the risk of

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Section: Discussionmentioning

confidence: 91%

A shortened activated partial thromboplastin time is associated with the risk of venous thromboembolism

Tripodi

Chantarangkul

Martinelli

et al. 2004

Blood

181

128

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“…Additionally, with an insensitive aPTT reagent, factor assays are the best method for following-up the factor levels in a patient. However, with a sensitive reagent, the aPTT may be used to follow-up replacement therapy (14). Our patient demonstrates that the sensitivity of some aPTT reagents is not sufficient to detect all cases of factor XI deficiency.…”

Section: Discussionmentioning

confidence: 87%

“…The normal aPTT was confirmed on a second preoperative specimen. Various aPTT reagents have different sensitivities to low factor levels (13)(14)(15). In our recent work, the sensitivities of five commercial aPTT reagents for factor XI ranged from 35 to 42% (13).…”

Section: Discussionmentioning

confidence: 99%

Unique Case of Brothers with Moderate Factor XI Deficiency and One with Severe Bleeding After Surgery

Steel

Hassell

Rajagopalan

et al. 1996

Clin Appl Thromb Hemost

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Factor XI is the only contact factor whose deficiency may result in a bleeding diathesis. This case report describes two brothers with similar moderate factor XI deficiency (41% and 45%), but one brother had severe bleeding during invasive procedures whereas the other brother undergoing the same surgical procedure had no excessive bleeding. The bleeding in the first brother continued despite adequate factor XI levels; however, it was stopped only after EACA therapy. Also discussed is the importance of a sensitive aPTT reagent to the various factors and the role of the aPTT in predicting potential bleeding, since a normal aPTT was obtained prior to the first surgery. This case demonstrates that major bleeding can occur in heterozygous factor XI deficiency and the patient must be considered 'at risk' for potential bleeding and should be treated accordingly.

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“…Die statistischen Berechnungen erfolgten nach dem Wilcoxon D-Test (8,9,10) Erwachsene (n = 69) F IX (%) Kinder (n=92) als Aktivator gemeinsam die Ellagsäure und ein pflanzliches Phospholipid aus Sojabohnen, jedoch dürften die Stabilisatoren, die verwendeten Pufferlösungen und die Kalziumkonzentrationen unterschiedlich sein, was möglicherweise zu den oben erwähnten Differenzen geführt hat (12,13). Die Sensitivität gegenüber den Faktoren VIII und IX ist bei beiden Reagenzien gleich gut und höher als bei Reagenzien, die mit Kaolin oder Silicataktivierung arbeiten (11,13,14,15) und mit denen in den Jahren vor 1970 Normalwerte für die PTT ermittelt wurden.…”

Section: Introductionunclassified

“…Dadurch fand sich erwartungsgemäß, wie schon Tabelle 1 deutlich macht, eine Verschiebung der von der Firma angegebenen oberen Grenze von 35 Sekunden auf 38 Sekunden. Die angegebenen Richtwerte sollten mit den in der Klinik üblichen Abnahme-und Bestimmungstechniken überprüft werden, da große Streuungen beschrieben wurden (11,12,14,15,16). Die ermittelten 5., 50. und 95.…”

Section: Introductionunclassified

Partielle Thromboplastinzeit, Aktivitäten von Faktor VIII und Faktor IX bei klinisch unauffälligen Kindern im Vergleich mit gesunden Erwachsenen

Wanner¹,

Lange²,

Weiss³

et al. 1992

LaboratoriumsMedizin

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Zusammenfassung: Bei 92 klinisch unauffälligen Kindern im Alter von zwei bis zehn Jahren wurde die aktivierte Partielle Thromboplastinzeit (PTT) mit zwei verschiedenen Reagenzien gemessen und mit einem Kollektiv von 69 gesunden Erwachsenen verglichen. Überprüft werden sollte, inwieweit die Richtwerte für Erwachsene auch für diese Altersgruppe gelten. Bei der Neothromtin®-Methode fanden sich statistisch gesicherte Verlängerungen um fünf Sekunden gegenüber der 95. Percentile des Erwachsenenkollektivs (Erwachsene bis 38 sec, Kinder bis 43 sec). Bei der Actin®-FS-Methode konnte nur im Frischplasma eine statistisch gesicherte Differenz zwischen Erwachsenen-und Kinderkollektiv festgestellt werden (Erwachsene bis 39 sec, Kinder bis 40 sec). Die möglichen Ursachen wurden diskutiert und auf die Notwendigkeit hingewiesen, eigene Richtwerte unter den in der Klinik üblichen Bedingungen sowohl für Erwachsene als auch für Kinder zu erstellen. Schlüsselwörter: PTT-Kinder-Normalwerte -Faktor VIII -Faktor IX Summary: The aim of this study was to investigate whether the normal values of activated partial thromboplastin time for adults are also valid for children age two to ten. 92 children are compared with 69 adults applying two diffrerent reagents. With Neothromtin® a significant prolongation of five seconds were found (adults: upper level 38 see, children: upper level 43 sec). With Actin®-FS only in fresh plasma a statistically significant prolongation was obtained (adults upper level 39 sec, children: upper level 40 sec). The possible causes are discussed and it is pointed out that normal values of adults cannot be applied for pediatrics. Each clinical laboratory should determine its own reference values for adults and children. Abb. 4 a u. b: Darstellung der PTT-Werte in Sekunden gemessen mit Neothromtin 9 und der Faktor VIII-und IX-Aktivitäten in Prozent bei Kindern und Erwachsenen unter Angabe der 5. und 95. Percentile.

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Comparison of the Sensitivity of Commercial APTT Reagents in the Detection of Mild Coagulopathies

Cited by 27 publications

References 0 publications

A shortened activated partial thromboplastin time is associated with the risk of venous thromboembolism

A shortened activated partial thromboplastin time is associated with the risk of venous thromboembolism

Unique Case of Brothers with Moderate Factor XI Deficiency and One with Severe Bleeding After Surgery

Partielle Thromboplastinzeit, Aktivitäten von Faktor VIII und Faktor IX bei klinisch unauffälligen Kindern im Vergleich mit gesunden Erwachsenen

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