Poor Agreement among Prothrombin Time International Normalized Ratio Methods: Comparison of Seven Commercial Reagents

Horsti, Juha; Uppa, Helena; Vilpo, Juhani

doi:10.1373/clinchem.2004.043836

Cited by 67 publications

(69 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The present study demonstrated that testing of PTand INR in separate laboratories, by different instruments and reagents, might occasionally generate misleading clinical information. In our study, The statistically significant differences were observed when plasma samples from patients who receiving warfarin were tested for INR on three different Laboratories, which was agreed with study done by Fitzmaurice et al in which they compared the (INR) measurement in hospital and general practice settings, they found that there were significant differences between all hospital systems P value less than 0.05 [1].…”

Section: Discussionsupporting

confidence: 91%

See 1 more Smart Citation

Evaluation of Different Thromboplastins and Coagulometers on International Normalize Ratio (INR) Readings for Patients under Stable Oral Anticoagulant Therapy

Ahmed¹,

Muddathir²

2015

J Blood Disord Transfus

View full text Add to dashboard Cite

Background: Variations between various thromboplastin preparations have in the past led to decreased accuracy of INR readings. Because thromboplastin reagents vary widely in composition and manner of preparation, their sensitivity in monitoring oral anticoagulant therapy also vary widely. This study aimed to evaluate different thromboplastins and coagulometers on INR reading for patients under stable oral anticoagulant therapy.

show abstract

Section: Discussionsupporting

confidence: 91%

“…In 1983, the World Health Organization (WHO) adopted a method to establish consistency of the PT value for patient on AVK [1][2][3]. This mathematical expression of the PT value is termed INR [4].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Different Thromboplastins and Coagulometers on International Normalize Ratio (INR) Readings for Patients under Stable Oral Anticoagulant Therapy

Ahmed¹,

Muddathir²

2015

J Blood Disord Transfus

View full text Add to dashboard Cite

show abstract

“…A limited number of batches of reagent and calibrators were used in this study. Because there is no reference method for insulin or consensus on standard statistical techniques for such multiassay analyses (30 ), the mean insulin value for each sample was used as a common comparator. This approach may not be appropriate for a smaller number of assays.…”

Section: Discussionmentioning

confidence: 99%

Comparison of 11 Human Insulin Assays: Implications for Clinical Investigation and Research

Manley¹,

et al. 2007

View full text Add to dashboard Cite

Background: The American Diabetes Association task force on standardization of insulin assays in 1996 showed wide variation in assay bias. Newer assays are specific for insulin, with several now available on automated immunoassay analyzers. Methods: In 2004, we compared 11 commercially available insulin assays by analyzing 150 serum samples (99 fasting/51 postprandial) from study participants with various degrees of glucose intolerance (exclusions being type 1 diabetes, insulin treatment, or presence of insulin antibodies). All assays were calibrated against International Reference Preparation 66/304. One assay was not specific for insulin and another was an RIA; 10 assays used enzyme/chemiluminescent labels. Bland-Altman difference plots were modified to use the mean insulin from all assays on the x-axis as a common comparator. Results: As in the 1996 study, insulin values from the different assays varied by a factor of 2, with the nonspecific assay ranking in the middle of the distribution. Spearman rank correlation coefficients, for ranking samples vs the mean, were 0.983-0.997. Both offsets and concentration-dependent differences were seen in the modified difference plots. Imprecision (mean CV) for automated assays (3%) was not significantly different from manual assays (5%). Similar values were obtained when one automated assay was run in laboratories in both the UK and the US. Results of 1 assay showed lower insulin concentrations in heparinized plasma than in serum.

show abstract

“…The coagulation factors are pivotal in the extrinsic and common pathways and are evaluated through the prothrombin time test [10]. The coagulation factors of intrinsic pathways are assessed through activated partial thromboplastin time (APTT) test [11].…”

Section: Introductionmentioning

confidence: 99%

Activated Partial Thromboplastin Time, Prothrombin Time, Thrombin Time and Platelet Count Study in HIV Seropositive Subjects at Nnamdi Azikiwe Teaching Hospital Nnewi

Mo¹,

N²,

C³

et al. 2016

Transl Biomed

View full text Add to dashboard Cite

This study was aimed at evaluating the effect of HIV infection on hemostatic parameters, determination of the influence and duration of antiretroviral therapy (ART) on these parameters. It was carried out at the Nnamdi Azikiwe University Teaching Hospital, Nnewi. One hundred and eighty two subjects were recruited consisting; Sixty one (31 males and 30 females) HIV positive subjects on antiretroviral therapy (ART) with an ART duration of 6 months -2 years ≤5 years, ≤10 years; Sixty one (28 males and 33 females) HIV positive subjects ART naïve and Sixty (30 males and 30 females) seronegative (HIV negative control) subjects. The prothrombin time (PT) was determined using Quick One Stage method, activated partial thromboplastin time (APTT) was determined by Modified Kaolin method, thrombin time (TT) was done by Two stage method, HIV status was determined using Immunochromatographic method and Platelet count was determined using Direct current detection method. Student t-Test and ANOVA were used to analyze significance of differences in mean values between groups and among groups, respectively. PT and APTT for ART and Non-ART subjects were significantly increased compared with control (P<0.05 in each case). However, the PT and APTT compared between gender and also among duration of ART showed no significant difference (P>0.05 in each case). The TT was significantly higher in HIV-positive on ART compared to control (P<0.05). The gender and duration of ART did not show significant difference in the TT of the subjects (P>0.05 in each case). Platelet count was significantly lower in HIV-positive subjects (ART and Non-ART) compared to the values obtained in HIV negative subjects (P<0.05 in each case). However, the platelet count when compared between gender and also among duration of ART showed no significant difference (P>0.05 in each case). The reason for the increase in PT and APTT in HIV disease may be as a result of endothelial activation and liver derangement and decreased platelet count is due to cytopenias seen in HIV disease.

show abstract

Poor Agreement among Prothrombin Time International Normalized Ratio Methods: Comparison of Seven Commercial Reagents

Cited by 67 publications

References 26 publications

Evaluation of Different Thromboplastins and Coagulometers on International Normalize Ratio (INR) Readings for Patients under Stable Oral Anticoagulant Therapy

Evaluation of Different Thromboplastins and Coagulometers on International Normalize Ratio (INR) Readings for Patients under Stable Oral Anticoagulant Therapy

Comparison of 11 Human Insulin Assays: Implications for Clinical Investigation and Research

Activated Partial Thromboplastin Time, Prothrombin Time, Thrombin Time and Platelet Count Study in HIV Seropositive Subjects at Nnamdi Azikiwe Teaching Hospital Nnewi

Contact Info

Product

Resources

About