International Collaborative Study for the Calibration of a Proposed International Standard for thromboplastin, human, plain

Tripodi, Armando; Chantarangkul, Veena; Besselaar, A. M. H. P. Van Den; Witteveen, E.; Hubbard, A. R.

doi:10.1111/j.1538-7836.2010.03980.x

Cited by 14 publications

(15 citation statements)

References 4 publications

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“…The mainstay of the model is the preparation and provision of thromboplastin standards from different species, which are interrelated by iterative calibration (predecessor-to-successor) by means of international collaborative studies, which secure continuity of the system over time. Presently, there Log-PT with working thromboplastin Log-PT with international standard ISI = Slope X ISI of the international standard are two international standards available from WHO: RBT/05 from rabbit brain [12] and rTF/09 from human recombinant relipidated tissue factor [13]. The system of calibration based on the revised Kirkwood model is still in place, and is the focus of continuous attention aimed at improving its reliability.…”

Section: International Normalized Ratio (Inr)mentioning

confidence: 99%

How to report results of prothrombin and activated partial thromboplastin times

Tripodi

Lippi

Plebani

2016

Clinical Chemistry and Laboratory Medicine (CCLM)

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Prothrombin time (PT) and activated partial thromboplastin time (APTT) are the most widely used tests to investigate coagulation abnormalities. Varied result reporting have been introduced over the years for the two tests, thus making their interpretation rather confusing in different clinical settings. PT results have been reported as clotting time, percentage activity, PT-ratio (patient-tonormal clotting time) and as international normalized ratio (INR). The INR scale has been devised to harmonize results stemming from different thromboplastins from patients on treatment with vitamin K antagonists. Therefore, there are some theoretical and evidence-based considerations that make the INR formally invalid when the test is used to analyze patients in other clinical settings. Unfortunately, this limitation has been frequently overlooked, and the INR has been (and is currently) used as a universal system of results harmonization. The APTT has been historically reported as clotting time or as ratio (patient-to-normal clotting time). In this opinion paper we review the current state-of-the-art for result reporting and attempt to give practical guidance on how PT and APTT should be reported in different clinical conditions for which the tests are requested.

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Section: International Normalized Ratio (Inr)mentioning

confidence: 99%

How to report results of prothrombin and activated partial thromboplastin times

Tripodi

Lippi

Plebani

2016

Clinical Chemistry and Laboratory Medicine (CCLM)

View full text Add to dashboard Cite

show abstract

“…In the present article, we focus on the various contributions to the total analytical INR error within one laboratory including the effect of ISI uncertainty. If an international standard for thromboplastin is used for PT, MNPT, and INR assessment, an established value for the ISI is used that has been published in the scientific literature [3,4]. The multicenter studies for the establishment of an international standard have shown that there is considerable variation in the ISI for the standard [3,4].…”

Section: A M H P V a N D E N B E S S E L A A R E W I T T mentioning

confidence: 99%

“…international standard has not been used for the calculation of the uncertainty of the new international standard [3,4].…”

Section: A M H P V a N D E N B E S S E L A A R E W I T T mentioning

confidence: 99%

“…On the other hand, SD ISI represents mainly systematic error and is derived from the collaborative calibration studies [3,4]. We applied Equation 5 to PT data collected by one experienced technician in our laboratory.…”

Section: A M H P V a N D E N B E S S E L A A R E W I T T mentioning

confidence: 99%

“…SD log MNPT (geometric mean normal PT of the healthy adult population) is the between-exercise standard deviation of the log MNPT determined with 20 individual normal samples by the same technician. SD ISI is the between-laboratory standard deviation of the International Sensitivity Index (ISI) for RBT/05 and rTF/09 published previously [3,4] respectively. SD log INR is calculated with Equation 5.…”

Section: Disclosure Of Conflict Of Interestsmentioning

confidence: 99%

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