Test result variation and the quality of evidence-based clinical guidelines

Cg, Fraser

doi:10.1016/s0009-8981(04)00161-5

Cited by 12 publications

(17 citation statements)

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“…Therefore, statistically significance of the difference between two different conditions is easily reached, but may not be of clinical significance. As a consequence, the clinical relevance of the observed bias should be reviewed instead [7]. This approach allows a more relevant comparison of results obtained in samples containing a potentially interfering substance.…”

Section: Discussionmentioning

confidence: 99%

“…This relies on clinical acceptance criteria determined according to the CLSI C56-A guideline [3]. Accordingly, a clinically significant interference is evidenced when the test result in the presence of the interfering substance differs more than 1.96 9 (CVa2 + CVw2)1/ 4 from the result without the interfering substance (CVa is the analytical coefficient of variation, and CVw is the within-subject biological variation) [7]. Briefly, CVa was given by the manufacturer; it corresponds to the intraassay variability of each reagent.…”

Section: Statisticsmentioning

confidence: 99%

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Effects of haemolysis, icterus and lipaemia on coagulation tests as performed on Stago STA‐Compact‐Max analyser

Woolley

Golmard

Kitchen

2016

Int J Lab Hematology

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Summary Introduction Haemolysis, icterus and lipaemia (HIL) may affect haemostasis test results. This may be influenced by the level of interfering substance and the reagents and end‐point detection system used. Methods We assessed the influence of HIL on prothrombin time, activated partial thromboplastin time and fibrinogen assay using a viscosity‐based detection analyser. Results Spontaneous haemolysis that occurred during sample collection and processing had no effect on PT with either a rabbit tissue factor extract or recombinant human tissue factor reagents. In contrast, addition of mechanically haemolysed cells impacted on PT for the highest haemoglobin concentration. For APTTs determined with STA®‐Cephascreen® reagent, there was no significant difference between results in haemolysed and nonhaemolysed samples. For the other two reagents studied, APTTs were statistically significantly shorter in haemolysed samples compared with nonhaemolysed samples. This bias was clinically significant only for STA®‐PTT Automate. For all three APTT reagents, the impact of haemolysis was sufficient to impact patient management decisions, and in some samples, the effects of lipaemia and icterus were not clinically significant. Conclusion Overall, our results confirm that PT and fibrinogen were not clinically significantly affected by HIL. The APTTs of some haemolysed samples were falsely normal. Haemolysed samples for APTT determination should be rejected.

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Section: Discussionmentioning

confidence: 99%

Section: Statisticsmentioning

confidence: 99%

Effects of haemolysis, icterus and lipaemia on coagulation tests as performed on Stago STA‐Compact‐Max analyser

Woolley

Golmard

Kitchen

2016

Int J Lab Hematology

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“…We defined clinically significant interference when the result in the presence of the interferent differs more than 1.96 Â (CV a 2 þ CV w 2 ) 1 2 from the result without the interferent. 13 Half of this deviation we call the combined CV (CV c ). The index or interferent concentration above which there is clinically significant interference is called the clinical cut-off index or concentration.…”

Section: Statisticsmentioning

confidence: 99%

Evaluation of the interference due to haemoglobin, bilirubin and lipids on Immulite 2500 assays: a practical approach

et al. 2011

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Background: Interfering substances such as haemoglobin, bilirubin and lipids in a sample may lead to wrong interpretation of immunoassay results by the clinician. In general, there has been minor attention to these interferences on immunoassays, whereas these effects on chemical assays are frequently described. Information about interferences by haemoglobin, bilirubin and lipids on the Siemens Immulite 2500 assays in the instructions for use is falling short. Methods: Interferents in patient samples can be measured reliably in a semi-quantitative way on most chemistry analysers and can be expressed in haemolysis-, icterus-and lipaemia-indices. As the Immulite 2500 cannot perform such measurements, samples are normally analysed without testing for the presence of interferents. Therefore, a study was carried out to examine these interferences on 24 Immulite 2500 assays. Samples were spiked with increasing concentrations of either haemoglobin, bilirubin or lipids. The haemolysis-, icterus-and lipaemia-indices were measured on a Synchron DxC 800 analyser. Results: Based on analytical imprecision and intraindividual biological variation of each analyte, cut-off indices above which clinically significant interference exists were determined. We found clinically significant interference due to haemoglobin on ferritin and folate, by bilirubin on oestradiol and testosterone and by lipids on testosterone. Conclusions: Introducing cut-off indices prevents reporting of wrong Immulite 2500 results due to interference. Our results are applicable in laboratories using any chemistry analyser capable of reporting semi-quantitative concentrations of interferents.

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“…There are two types of variation associated with the intra-individual variation of sperm parameters after sperm preparation. First, ''analytical variation'' can be measured by quantifying the imprecision defined as the closeness of agreement between independent results of measurement obtained under stipulated conditions [Fraser 2004]. The other source of variation is the ''biologic variation'' i.e., the closeness of the sperm parameters to a homeostatic ''setting point'' for each individual [Fraser 2004].…”

mentioning

confidence: 99%

“…First, ''analytical variation'' can be measured by quantifying the imprecision defined as the closeness of agreement between independent results of measurement obtained under stipulated conditions [Fraser 2004]. The other source of variation is the ''biologic variation'' i.e., the closeness of the sperm parameters to a homeostatic ''setting point'' for each individual [Fraser 2004]. It is not clear what determines the ''setting point'' in semen production, whether it's the semen concentration, motility, total motile sperm or other parameter(s) [Alvarez et al 2003].…”

mentioning

confidence: 99%

Effect of Sperm Preparation Techniques by Density Gradient on Intra-Individual Variation of Sperm Motility

Hammoud

Gibson

Peterson

et al. 2007

Archives of Andrology

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Test result variation and the quality of evidence-based clinical guidelines

Cited by 12 publications

References 0 publications

Effects of haemolysis, icterus and lipaemia on coagulation tests as performed on Stago STA‐Compact‐Max analyser

Effects of haemolysis, icterus and lipaemia on coagulation tests as performed on Stago STA‐Compact‐Max analyser

Evaluation of the interference due to haemoglobin, bilirubin and lipids on Immulite 2500 assays: a practical approach

Effect of Sperm Preparation Techniques by Density Gradient on Intra-Individual Variation of Sperm Motility

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