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Systematic review of critical risk result alert thresholds
S96
PATHOLOGY 2017 ABSTRACT SUPPLEMENT
HDL, calculated LDL, Triglycerides were analysed for variations amongst specific patient cohorts. Results: As previously described, non-fasting triglyceride results had a higher mean for all patient cohorts. However, an intriguing pattern was observed with both Total cholesterol and HDL demonstrating higher fasting levels. Of the non-fasting samples, approximately 9% of samples had a triglyceride level greater than 5 mmol/L and therefore may need to be recollected as fasting. Conclusion: Whilst these results are largely consistent with published data, there are slight differences between fasting and non-fasting lipid results. References 1. National Vascular Disease Prevention Alliance (NVDPA). Guidelines for the Management of Absolute Cardiovascular Disease Risk. NVDPA, 2012 2. Nordestgaard BG, Langsted A, Mora S, et al. Fasting is not routinely required for determination of a lipid profile: clinical and laboratory implications including flagging at desirable concentration cutpoints – A Joint Consensus Statement from the European Atherosclerosis Society and European Federation of Clinical Chemistry and Laboratory Medicine. Clin Chem 2016; 62: 930–46.
SYSTEMATIC REVIEW OF CRITICAL RISK RESULT ALERT THRESHOLDS Craig A. Campbell1,2, Andrew Georgiou1, Johanna I. Westbrook1, Andrea R. Horvath2 1 The Centre for Health Systems and Safety Research (CHSSR), Australian Institute of Health Innovation, Macquarie University, and 2Department of Clinical Chemistry and Endocrinology, South Eastern Area Laboratory Services, NSW Health Pathology, NSW, Australia Background: Pathology laboratories are required to immediately report results which indicate a patient is at critical risk, but there is little consensus about what values are critical. The aim of this review was to systematically review the literature on adult alert thresholds for common chemistry and haematology tests, and provide an explicit and ranked source of this evidence. Methods: The literature search covered the period of 1995–2014. Evidence sources were critically appraised and ranked using the 1999 Stockholm hierarchy for analytical performance specifications in laboratory medicine modified for establishing decision limits. Results: The 30 most frequently reported laboratory tests with alert thresholds are presented with evidence rankings. Seventy percent of papers reported thresholds set by individual institutions, while 18% contained thresholds from surveys of laboratories or clinicians. ‘Starter sets’ of alert thresholds were recommended by six professional bodies, three of which were collaborations between pathologists and clinicians. None of the nine outcome studies identified dealt with confounding factors. Conclusions: Recommendations by professional bodies based on outdated surveys or consensus are currently the best sources of evidence for building alert lists. Well-designed outcome studies and greater collaboration between clinicians and laboratories are needed to identify the most appropriate alert thresholds. Reference Campbell CA, Georgiou A, Westbrook JI, et al. What alert thresholds should be used to identify critical risk results: a systematic review of the evidence. Clin Chem 2016; 62:1445–57.
Pathology (2017), 49(S1)
BIOTIN INTERFERENCE WITH ROUTINE IMMUNOASSAYS Kay Weng Choy1, Nilika Wijeratne1,2,3, James C. G. Doery1,3 1 Monash Pathology, Monash Health, 2Dorevitch Pathology, Heidelberg, and 3Department of Medicine, Monash University, Vic, Australia Aim: Biotin is used to treat some rare inborn errors of metabolism. Recently, high doses of biotin have been prescribed to patients with multiple sclerosis. Exogenous biotin can interfere with immunoassays that use biotin-streptavidin interaction. We aimed to confirm the biotin interference on different immunoassays. Methods: One of the authors ingested 300 mg of biotin and blood specimens were collected at baseline, 4 hours, 24 hours, 2 days, 3 days and 4 days following ingestion. Serum specimens were tested on Beckman DxI, Roche Cobas and Siemens Centaur for immunoassays with biotin-streptavidin interaction. Results: In competitive immunoassays based on biotin-streptavidin interaction, excess biotin in the specimen competes with the biotinylated analogue for the binding sites on streptavidin resulting in falsely high values. This was evident most markedly with Centaur DHEAS and folate as well as DxI fT4 and fT3 at 4hour post biotin ingestion. In the sandwich immunoassays, excess biotin displaces biotinylated antibodies resulting in falsely low results. This was marked with Roche C-telopeptide, P1NP and thyroglobulin. For some assays, the effect lasted for 4 days post-ingestion. Discussion: Clinicians and the laboratory must be aware of this interference. Specific algorithms could be incorporated into the laboratory information system to detect such interference. A STATEWIDE INTERNAL QUALITY CONTROL PROCEDURE FOR GENERAL CHEMISTRY: AN UPDATE Gemma M. Daley, Karen Noy, Mary Hardwick, David Clarke, Nigel Brown Department of Chemical Pathology, Pathology Queensland Central Laboratory, Herston Hospital Campus, Herston, Qld, Australia Promoting accurate and precise result reporting through robust quality control (QC) process is critical to the practice of a pathologist. We present Pathology Queensland’s model of a Statewide QC program to streamline assay performance monitoring.1 Introduced in 2009 across 35 laboratories, a single target for the majority of analysers is provided by the reference laboratory using the 12.5 rule of Blum.2 Laboratories are supplied with new lots of QC material accompanied by provisional targets on a continuous basis with final targets set according to Statewide performance. Furthermore, the introduction of Unity Real Time in July 2013, a QC software package, saw the implementation of a common QC reporting platform. Monthly reports are generated and distributed whereby performance of individual laboratories can be critically analysed. This platform has allowed a more efficient and transparent analysis of Statewide QC data in addition to enabling laboratories to compare their performance to other laboratories in the network. In addition to the introduction of this program it is required that QC plots are reviewed daily at minimum to ensure any potential decline in assay performance is identified promptly.
PATHOLOGY 2017 ABSTRACT SUPPLEMENT
HDL, calculated LDL, Triglycerides were analysed for variations amongst specific patient cohorts. Results: As previously described, non-fasting triglyceride results had a higher mean for all patient cohorts. However, an intriguing pattern was observed with both Total cholesterol and HDL demonstrating higher fasting levels. Of the non-fasting samples, approximately 9% of samples had a triglyceride level greater than 5 mmol/L and therefore may need to be recollected as fasting. Conclusion: Whilst these results are largely consistent with published data, there are slight differences between fasting and non-fasting lipid results. References 1. National Vascular Disease Prevention Alliance (NVDPA). Guidelines for the Management of Absolute Cardiovascular Disease Risk. NVDPA, 2012 2. Nordestgaard BG, Langsted A, Mora S, et al. Fasting is not routinely required for determination of a lipid profile: clinical and laboratory implications including flagging at desirable concentration cutpoints – A Joint Consensus Statement from the European Atherosclerosis Society and European Federation of Clinical Chemistry and Laboratory Medicine. Clin Chem 2016; 62: 930–46.
SYSTEMATIC REVIEW OF CRITICAL RISK RESULT ALERT THRESHOLDS Craig A. Campbell1,2, Andrew Georgiou1, Johanna I. Westbrook1, Andrea R. Horvath2 1 The Centre for Health Systems and Safety Research (CHSSR), Australian Institute of Health Innovation, Macquarie University, and 2Department of Clinical Chemistry and Endocrinology, South Eastern Area Laboratory Services, NSW Health Pathology, NSW, Australia Background: Pathology laboratories are required to immediately report results which indicate a patient is at critical risk, but there is little consensus about what values are critical. The aim of this review was to systematically review the literature on adult alert thresholds for common chemistry and haematology tests, and provide an explicit and ranked source of this evidence. Methods: The literature search covered the period of 1995–2014. Evidence sources were critically appraised and ranked using the 1999 Stockholm hierarchy for analytical performance specifications in laboratory medicine modified for establishing decision limits. Results: The 30 most frequently reported laboratory tests with alert thresholds are presented with evidence rankings. Seventy percent of papers reported thresholds set by individual institutions, while 18% contained thresholds from surveys of laboratories or clinicians. ‘Starter sets’ of alert thresholds were recommended by six professional bodies, three of which were collaborations between pathologists and clinicians. None of the nine outcome studies identified dealt with confounding factors. Conclusions: Recommendations by professional bodies based on outdated surveys or consensus are currently the best sources of evidence for building alert lists. Well-designed outcome studies and greater collaboration between clinicians and laboratories are needed to identify the most appropriate alert thresholds. Reference Campbell CA, Georgiou A, Westbrook JI, et al. What alert thresholds should be used to identify critical risk results: a systematic review of the evidence. Clin Chem 2016; 62:1445–57.
Pathology (2017), 49(S1)
BIOTIN INTERFERENCE WITH ROUTINE IMMUNOASSAYS Kay Weng Choy1, Nilika Wijeratne1,2,3, James C. G. Doery1,3 1 Monash Pathology, Monash Health, 2Dorevitch Pathology, Heidelberg, and 3Department of Medicine, Monash University, Vic, Australia Aim: Biotin is used to treat some rare inborn errors of metabolism. Recently, high doses of biotin have been prescribed to patients with multiple sclerosis. Exogenous biotin can interfere with immunoassays that use biotin-streptavidin interaction. We aimed to confirm the biotin interference on different immunoassays. Methods: One of the authors ingested 300 mg of biotin and blood specimens were collected at baseline, 4 hours, 24 hours, 2 days, 3 days and 4 days following ingestion. Serum specimens were tested on Beckman DxI, Roche Cobas and Siemens Centaur for immunoassays with biotin-streptavidin interaction. Results: In competitive immunoassays based on biotin-streptavidin interaction, excess biotin in the specimen competes with the biotinylated analogue for the binding sites on streptavidin resulting in falsely high values. This was evident most markedly with Centaur DHEAS and folate as well as DxI fT4 and fT3 at 4hour post biotin ingestion. In the sandwich immunoassays, excess biotin displaces biotinylated antibodies resulting in falsely low results. This was marked with Roche C-telopeptide, P1NP and thyroglobulin. For some assays, the effect lasted for 4 days post-ingestion. Discussion: Clinicians and the laboratory must be aware of this interference. Specific algorithms could be incorporated into the laboratory information system to detect such interference. A STATEWIDE INTERNAL QUALITY CONTROL PROCEDURE FOR GENERAL CHEMISTRY: AN UPDATE Gemma M. Daley, Karen Noy, Mary Hardwick, David Clarke, Nigel Brown Department of Chemical Pathology, Pathology Queensland Central Laboratory, Herston Hospital Campus, Herston, Qld, Australia Promoting accurate and precise result reporting through robust quality control (QC) process is critical to the practice of a pathologist. We present Pathology Queensland’s model of a Statewide QC program to streamline assay performance monitoring.1 Introduced in 2009 across 35 laboratories, a single target for the majority of analysers is provided by the reference laboratory using the 12.5 rule of Blum.2 Laboratories are supplied with new lots of QC material accompanied by provisional targets on a continuous basis with final targets set according to Statewide performance. Furthermore, the introduction of Unity Real Time in July 2013, a QC software package, saw the implementation of a common QC reporting platform. Monthly reports are generated and distributed whereby performance of individual laboratories can be critically analysed. This platform has allowed a more efficient and transparent analysis of Statewide QC data in addition to enabling laboratories to compare their performance to other laboratories in the network. In addition to the introduction of this program it is required that QC plots are reviewed daily at minimum to ensure any potential decline in assay performance is identified promptly.