Mis-identification of factor inhibitors by diagnostic haemostasis laboratories: recognition of pitfalls and elucidation of strategies. A follow up to a large multicentre evaluation

Favaloro, Emmanuel J.; Bonar, Roslyn; Duncan, Elizabeth M.; Earl, Gail; Low, Joyce; Aboud, Margaret; Just, Sarah; Sioufi, John; Street, Alison; Marsden, Kate

doi:10.1080/00313020701569998

Cited by 48 publications

(85 citation statements)

References 19 publications

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“…The exception was the lack of an incubation step in the mixing studies, which were equally distributed between the analyzed laboratory groups (Table 3), probably due to the rare occurrence of coagulation inhibitors [6,23]. In agreement with the findings of this study, failure to detect coagulation inhibitors in samples due to the lack of an incubation step has even been observed in specialized coagulation laboratories [18,24].…”

Section: Investigations Of Uapttssupporting

confidence: 87%

An international study of how laboratories handle and evaluate patient samples after detecting an unexpected APTT prolongation

Ajzner

Rogić

Meijer³

et al. 2015

Clinical Chemistry and Laboratory Medicine (CCLM)

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Background: An unexpectedly detected prolonged activated partial thromboplastin time (APTT) can be a harmless laboratory finding, but can also reflect a thrombotic tendency or a bleeding disorder. The assistance of laboratory professionals in the interpretation of an unexpectedly detected prolonged APTT (uAPTT) is often required. The way in which uAPTTs are evaluated in laboratories was assessed in this international study with the aim of determining whether laboratory professionals are able to fulfill this need. Methods: Postanalytical practices after uAPTT were investigated and the mixing study methodology (if used) was studied by circulating a case report with a questionnaire to staff in the invited laboratories. In addition, the interpretations of those staff regarding the presence or absence

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Section: Investigations Of Uapttssupporting

confidence: 87%

An international study of how laboratories handle and evaluate patient samples after detecting an unexpected APTT prolongation

Ajzner

Rogić

Meijer³

et al. 2015

Clinical Chemistry and Laboratory Medicine (CCLM)

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“…A large assessment was recently undertaken in 2005 that utilized a wide range of test material that either contained true factor inhibitors, or else material that could reflect possible false identification of such inhibitors [9,10]. The current report is of several more recent exercises specifically related to the identification of inhibitors to FVIII, the most common laboratory and clinical presentation of factor inhibitors.…”

Section: Methodsmentioning

confidence: 97%

Laboratory identification of factor VIII inhibitors in the real world: the experience from Australasia

et al. 2010

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The laboratory has a key role in the initial detection of factor inhibitors and an ongoing role in the measurement of inhibitor titres during the course of inhibitor eradication therapy. The most commonly seen factor inhibitors are those directed against factor VIII (FVIII), usually detected either using the original or Nijmegen-modified Bethesda assay. In view of previously demonstrated high variability in laboratory results for inhibitor assays, we have more extensively examined laboratory performance in the identification of FVIII inhibitors. Over the past 3 years, we conducted two questionnaire-based surveys and two wet-challenge surveys utilizing eight samples comprising no FVIII inhibitor (n = 1), or low-titre (n = 2), medium-titre (n = 3) or high-titre (n = 2) FVIII inhibitor. Four samples were tested by 42 laboratories in 2007, and four by 52 laboratories in 2009. High inter-laboratory variation was evident, with CVs around 50% not uncommon, and some 10% of all laboratories (or around 15% of laboratories using Bethesda method) failed to detect low-level inhibitors of around 1 BU mL(-1). Laboratories using the Nijmegen method appeared to perform better than those using a standard Bethesda assay, with lower evident assay variation and no false negatives. There was a wide variety of laboratory practice, with no two laboratories using exactly the same process for testing and interpretation of factor inhibitor findings. In conclusion, our study indicates that there is still much need for standardization and improvement in factor inhibitor detection, and we hope that our findings provide a basis for future improvements in this area.

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“…To our knowledge, such an evaluation has not been performed previously. Favaloro and colleagues utilized an EDTA plasma sample within an external quality assessment exercise designed to evaluate the potential effect of a variety of anticoagulant samples as potential pre‐analytical variables in coagulation testing . For the participant‐blind‐tested EDTA sample, which utilized EDTA at the same concentration normally found in an EDTA collection tube, a gross prolongation of PT and APTT was reported by all participants performing such tests, with mixing studies showing only partial correction.…”

Section: Discussionmentioning

confidence: 99%

Sodium citrate blood contamination by K₂‐ethylenediaminetetraacetic acid (EDTA): impact on routine coagulation testing

Lima-Oliveira

Salvagno

Danese

et al. 2014

Int J Lab Hematology

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Mis-identification of factor inhibitors by diagnostic haemostasis laboratories: recognition of pitfalls and elucidation of strategies. A follow up to a large multicentre evaluation

Cited by 48 publications

References 19 publications

An international study of how laboratories handle and evaluate patient samples after detecting an unexpected APTT prolongation

An international study of how laboratories handle and evaluate patient samples after detecting an unexpected APTT prolongation

Laboratory identification of factor VIII inhibitors in the real world: the experience from Australasia

Sodium citrate blood contamination by K₂‐ethylenediaminetetraacetic acid (EDTA): impact on routine coagulation testing

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Mis-identification of factor inhibitors by diagnostic haemostasis laboratories: recognition of pitfalls and elucidation of strategies. A follow up to a large multicentre evaluation

Cited by 48 publications

References 19 publications

An international study of how laboratories handle and evaluate patient samples after detecting an unexpected APTT prolongation

An international study of how laboratories handle and evaluate patient samples after detecting an unexpected APTT prolongation

Laboratory identification of factor VIII inhibitors in the real world: the experience from Australasia

Sodium citrate blood contamination by K2‐ethylenediaminetetraacetic acid (EDTA): impact on routine coagulation testing

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Sodium citrate blood contamination by K₂‐ethylenediaminetetraacetic acid (EDTA): impact on routine coagulation testing