Australasian Association Of Clinical Biochemists Research Articles

Proceedings of the Australasian Association of Clinical Biochemists’ 57th Annual Scientific Conference

Over the past decade, there has been much interest in the biology and diagnostic applications of cell-free nucleic acids in plasma. Research in this area started with the demonstration of tumour-derived DNA and RNA molecules in the plasma of cancer patients. My group has a longstanding interest in using this approach for the detection and monitoring of cancer common in China, including nasopharyngeal carcinoma and lung cancer. My interest has since expanded into other species of circulating nucleic acids and has led to the discovery of cell-free fetal DNA and RNA in the plasma of pregnant women. The latter has allowed the non-invasive prenatal diagnosis of a number of fetal genetic diseases and traits (e.g. RhD blood group) from maternal blood. Progress in this area has been accelerated with the development of a number of powerful analytical tools. Recent examples include microfluidics digital PCR and next-generation DNA sequencing.

An evidence- and risk-based approach to a harmonized laboratory alert list in Australia and New Zealand

Individual laboratories are required to compose an alert list for identifying critical and significant risk results. The high-risk result working party of the Royal College of Pathologists of Australasia (RCPA) and the Australasian Association of Clinical Biochemists (AACB) has developed a risk-based approach for a harmonized alert list for laboratories throughout Australia and New Zealand. The six-step process for alert threshold identification and assessment involves reviewing the literature, rating the available evidence, performing a risk analysis, assessing method transferability, considering workload implications and seeking endorsement from stakeholders. To demonstrate this approach, a worked example for deciding the upper alert threshold for potassium is described. The findings of the worked example are for infants aged 0-6 months, a recommended upper potassium alert threshold of >7.0 mmol/L in serum and >6.5 mmol/L in plasma, and for individuals older than 6 months, a threshold of >6.2 mmol/L in both serum and plasma. Limitations in defining alert thresholds include the lack of well-designed studies that measure the relationship between high-risk results and patient outcomes or the benefits of treatment to prevent harm, and the existence of a wide range of clinical practice guidelines with conflicting decision points at which treatment is required. The risk-based approach described presents a transparent, evidence- and consensus-based methodology that can be used by any laboratory when designing an alert list for local use. The RCPA-AACB harmonized alert list serves as a starter set for further local adaptation or adoption after consultation with clinical users.

Polyuria‐polydipsia syndrome: a diagnostic challenge

The main determinants for the maintenance of water homeostasis are the hormone arginine vasopressin (AVP) and thirst. Disturbances in these regulatory mechanisms can lead to polyuria-polydipsia syndrome, which comprises of three different conditions: central diabetes insipidus (DI) due to insufficient secretion of AVP, nephrogenic DI caused by renal insensitivity to AVP action and primary polydipsia due to excessive fluid intake and consequent physiological suppression of AVP. It is crucial to determine the exact diagnosis because treatment strategies vary substantially. To differentiate between the causes of the polyuria-polydipsia syndrome, a water deprivation test combined with desmopressin administration is the diagnostic 'gold standard'. Thereby, AVP activity is indirectly evaluated through the measurement of urine osmolality after prolonged dehydration. However, this test has several limitations and may fail to distinguish precisely between patients with primary polydipsia and mild forms of central and nephrogenic DI. The direct measurement of AVP during the water deprivation test, which was reported in the 1980s, has not been widely adopted due to availability, assay issues and diagnostic performance. Recently, copeptin, the c-terminal portion of the larger precursor peptide of AVP, has been evaluated in the setting of polyuria-polydipsia syndrome and appears to be a useful candidate biomarker for the differential diagnosis. A standardised method for the water deprivation test is presented as part of a joint initiative of the Endocrine Society of Australia, the Australasian Association of Clinical Biochemists and the Royal College of Pathologists of Australasia to harmonise dynamic endocrine tests across Australia.

Challenging assay robustness with RCPAQAP external quality assurance programs

Background: External quality assurance (EQA) programs commonly test for precision and accuracy of quantitative assays, but less frequently for common interferences that could potentially impact patient results. RCPA Quality Assurance Programs (RCPAQAP) in conjunction with the Australasian Association of Clinical Biochemists (AACB) now includes challenge samples in Chemical Pathology programs.

An update report on the harmonization of adult reference intervals in Australasia.

The Australasian Association of Clinical Biochemists (AACB) has over the past 5 years been actively working to achieve harmonized reference intervals (RIs) for common clinical chemistry analytes using an evidence-based checklist approach where there is sound calibration and metrological traceability. It has now recommended harmonized RIs for 18 common clinical chemistry analytes which are performed in most routine laboratories and these have been endorsed by the Royal College of Pathologists of Australasia (RCPA). In 2017 another group of analytes including urea, albumin and arterial blood gas parameters were considered and suggested harmonized RIs proposed. This report provides an update of those harmonization efforts.

Minimum requirements for the estimation of measurement uncertainty: Recommendations of the joint Working group for uncertainty of measurement of the CSMBLM and CCMB.

The International vocabulary of metrology – Basic and general concepts and associated terms (VIM3, 2.26 measurement uncertainty, JCGM 200:2012) defines uncertainty of measurement as a non-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand, based on the information obtained from performing the measurement. Clinical Laboratory Standards Institute (CLSI) has published a very detailed guideline with a description of sources contributing to measurement uncertainty as well as different approaches for the calculation (Expression of measurement uncertainty in laboratory medicine; Approved Guideline, CLSI C51-A 2012). Many other national and international recommendations and original scientific papers about measurement uncertainty estimation have been published. In Croatia, the estimation of measurement uncertainty is obligatory for accredited medical laboratories. However, since national recommendations are currently not available, each of these laboratories uses a different approach in measurement uncertainty estimation. The main purpose of this document is to describe the minimal requirements for measurement uncertainty estimation. In such way, it will contribute to the harmonization of measurement uncertainty estimation, evaluation and reporting across laboratories in Croatia. This recommendation is issued by the joint Working group for uncertainty of measurement of the Croatian Society for Medical Biochemistry and Laboratory Medicine and Croatian Chamber of Medical Biochemists. The document is based mainly on the recommendations of Australasian Association of Clinical Biochemists (AACB) Uncertainty of Measurement Working Group and is intended for all medical biochemistry laboratories in Croatia.

Uptake of recommended common reference intervals for chemical pathology in Australia.

Background Reference intervals are a vital part of reporting numerical pathology results. It is known, however, that variation in reference intervals between laboratories is common, even when analytical methods support common reference intervals. In response to this, in Australia, the Australasian Association of Clinical Biochemists together with the Royal College of Pathologists of Australasia published in 2014 a set of recommended common reference intervals for 11 common serum analytes (sodium, potassium, chloride, bicarbonate, creatinine male, creatinine female, calcium, calcium adjusted for albumin, phosphate, magnesium, lactate dehydrogenase, alkaline phosphatase and total protein). Methods Uptake of recommended common reference intervals in Australian laboratories was assessed using data from four annual cycles of the RCPAQAP reference intervals external quality assurance programme. Results Over three years, from 2013 to 2016, the use of the recommended upper and lower reference limits has increased from 40% to 83%. Nearly half of the intervals in use by enrolled laboratories in 2016 have been changed in this time period, indicating an active response to the guidelines. Conclusions These data support the activities of the Australasian Association of Clinical Biochemists and Royal College of Pathologists of Australasia in demonstrating a change in laboratory behaviour to reduce unnecessary variation in reference intervals and thus provide a consistent message to doctor and patients irrespective of the laboratory used.

Reporting unit size and measurement uncertainty: current Australian practice in clinical chemistry and haematology

In this study we aimed to compare the reporting unit size used by Australian laboratories for routine chemistry and haematology tests to the unit size used by learned authorities and in standard laboratory textbooks and to the justified unit size based on measurement uncertainty (MU) estimates from quality assurance program data. MU was determined from Royal College of Pathologists of Australasia (RCPA) - Australasian Association of Clinical Biochemists (AACB) and RCPA Haematology Quality Assurance Program survey reports. The reporting unit size implicitly suggested in authoritative textbooks, the RCPA Manual, and the General Serum Chemistry program itself was noted. We also used published data on Australian laboratory practices.The best performing laboratories could justify their chemistry unit size for 55% of analytes while comparable figures for the 50% and 90% laboratories were 14% and 8%, respectively. Reporting unit size was justifiable for all laboratories for red cell count, >50% for haemoglobin but only the top 10% for haematocrit. Few, if any, could justify their mean cell volume (MCV) and mean cell haemoglobin concentration (MCHC) reporting unit sizes.The reporting unit size used by many laboratories is not justified by present analytical performance. Using MU estimates to determine the reporting interval for quantitative laboratory results ensures reporting practices match local analytical performance and recognises the inherent error of the measurement process.

Lab tests online Australasia

Lab Tests Online Australasia is a patient-centred website providing information on pathology testing (http://www.labtestsonline. org.au/). There is also an app that can be downloaded. While the primary purpose of this website is to provide information to patients, caregivers, and their families, it is also used by general practitioners, nurses and medical students to gain up to date information on diagnostic testing. It is a peer-reviewed, noncommercial entity providing information on tests, sample collection and clinical associations. The site is managed by the Australasian Association of Clinical Biochemists (AACB) with support from the Royal College of Pathologists of Australasia (RCPA) and a funding grant from the Quality Use of Pathology Program (Commonwealth Department of Health and Ageing). The site is accredited by HONcode, which is an ethical standard aimed at offering quality health information. As part of this accreditation the site is fully reviewed every 3 years to ensure content is current and correct. For immunology, this is currently performed by Dr Daman Langguth who has been instrumental in updating and modifying content for the Australian market.

Mass or molar? Recommendations for reporting concentrations of therapeutic drugs

A working party (WP) from the Australasian Association of Clinical Biochemists, Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists, Royal College of Pathologists of Australasia and Royal Australasian College of Physicians recommends the following: *mass units should be used for reporting therapeutic drug concentrations in Australia and New Zealand; and the litre (L) should be used as the denominator when expressing concentration. Examples of these units are mg/L and μg/L Exceptions to these principles include: *drugs for which there is current uniformity of reporting and supporting information using molar units, notably lithium (mmol/L) and methotrexate (μmol/L); *drugs that are also present as endogenous substances, where the units used routinely should continue to be used. This applies to many substances, including minerals (eg, iron; μmol/L), vitamins (eg, vitamin D; nmol/L) and hormones (eg, thyroxine; pmol/L). *drugs for which the denominator is not a 198 of fluid and there is international uniformity of reporting (eg, thiopurine metabolites; per 109 red blood cells). These recommendations relate to drugs that are used therapeutically, whether measured for therapeutic drug monitoring purposes or for assessment of overdose. Other substances, such as drugs of misuse, heavy metals or environmental toxins, were not considered by the WP and are thus not covered by this document. These recommendations should also be applied to other supporting documentation such as published guidelines, journal articles and websites. The implementation of these recommendations in New Zealand is subject to local confirmation.

Experience with a large point of care testing network

Introduction PoCT is an important enabler of evidence-based cardiac care allowing safe risk stratification and management of patients across country hospitals. Success of a large network relies on good communication, user-friendly instructions, effective IT, flexible training programs and good support systems. Methods The Integrated Cardiovascular Clinical Network Country Health SA (iCCnet CHSA) provides face to face and videoconferencing training, online education and competencies for PoCT operators. Online resources are located on the iCCnet CHSA website (www.iccnetsa.org.au) and 24/7 technical support is provided to PoCT operators. Results iCC net CHSA supports PoCT across country hospitals in South Australia. PoCT is managed by clinical network scientists complying with recommendations set by professional organisations such as the Australasian Association of Clinical Biochemists. They ensure all hospitals are involved in quality programs and have access to training when required. Because of staff resources across country, a variety of options for training PoCT operators are provided, ensuring it is accessible to all staff when convenient. Conclusions iCCnet CHSA removes the barriers to access education, training and support to allow the operation of PoCT within a quality framework in the management of cardiovascular disease. PoCT has been integral component to the improved cardiac outcomes reported by iCCnet CHSA. PoCT is an important enabler of evidence-based cardiac care allowing safe risk stratification and management of patients across country hospitals. Success of a large network relies on good communication, user-friendly instructions, effective IT, flexible training programs and good support systems. The Integrated Cardiovascular Clinical Network Country Health SA (iCCnet CHSA) provides face to face and videoconferencing training, online education and competencies for PoCT operators. Online resources are located on the iCCnet CHSA website (www.iccnetsa.org.au) and 24/7 technical support is provided to PoCT operators. iCC net CHSA supports PoCT across country hospitals in South Australia. PoCT is managed by clinical network scientists complying with recommendations set by professional organisations such as the Australasian Association of Clinical Biochemists. They ensure all hospitals are involved in quality programs and have access to training when required. Because of staff resources across country, a variety of options for training PoCT operators are provided, ensuring it is accessible to all staff when convenient. iCCnet CHSA removes the barriers to access education, training and support to allow the operation of PoCT within a quality framework in the management of cardiovascular disease. PoCT has been integral component to the improved cardiac outcomes reported by iCCnet CHSA.

Recommendations for standardized reporting of protein electrophoresis in Australia and New Zealand

Although protein electrophoresis of serum (SPEP) and urine (UPEP) specimens is a well-established laboratory technique, the reporting of results using this important method varies considerably between laboratories. The Australasian Association of Clinical Biochemists recognized a need to adopt a standardized approach to reporting SPEP and UPEP by clinical laboratories. A Working Party considered available data including published literature and clinical studies, together with expert opinion in order to establish optimal reporting practices. A position paper was produced, which was subsequently revised through a consensus process involving scientists and pathologists with expertise in the field throughout Australia and New Zealand. Recommendations for standardized reporting of protein electrophoresis have been produced. These cover analytical requirements: detection systems; serum protein and albumin quantification; fractionation into alpha-1, alpha-2, beta and gamma fractions; paraprotein quantification; urine Bence Jones protein quantification; paraprotein characterization; and laboratory performance, expertise and staffing. The recommendations also include general interpretive commenting and commenting for specimens with paraproteins and small bands together with illustrative examples of reports. Recommendations are provided for standardized reporting of protein electrophoresis in Australia and New Zealand. It is expected that such standardized reporting formats will reduce both variation between laboratories and the risk of misinterpretation of results.

Change of HbA1c reporting to the new SI units

An international consensus statement recommends that dual reporting of haemoglobin A (HbA(1c)) levels--in the current units (percentage) and Système International (SI) units (mmol/mol)--be used as an interim measure for a 2-year transition period before progressing towards the use of SI units only. This recommendation is supported by the Australasian Association of Clinical Biochemists, the Australian Diabetes Educators Association, the Australian Diabetes Society and the Royal College of Pathologists of Australasia. The SI units are a true measure of HbA(1c) and remove potential confusion between HbA(1c) values and blood glucose values.

Quality assessment, standardization

Background: Although protein electrophoresis of serum (SPEP) and urine (UPEP) specimens is a well-established laboratory technique, the reporting of results using this important method varies considerably between laboratories. The Australasian Association of Clinical Biochemists recognized a need to adopt a standardized approach to reporting SPEP and UPEP by clinical laboratories. Methods: A Working Party considered available data including published literature and clinical studies, together with expert opinion in order to establish optimal reporting practices. A position paper was produced, which was subsequently revised through a consensus process involving scientists and pathologists with expertise in the field throughout Australia and New Zealand. Results: Recommendations for standardized reporting of protein electrophoresis have been produced. These cover analytical requirements: detection systems; serum protein and albumin quantification; fractionation into alpha-1, alpha-2, beta and gamma fractions; paraprotein quantification; urine Bence Jones protein quantification; paraprotein characterization; and laboratory performance, expertise and staffing. The recommendations also include general interpretive commenting and commenting for specimens with paraproteins and small bands together with illustrative examples of reports. Conclusions: Recommendations are provided for standardized reporting of protein electrophoresis in Australia and New Zealand. It is expected that such standardized reporting formats will reduce both variation between laboratories and the risk of misinterpretation of results.

Creatinine eGFR and all that, an update

The introduction of routine reporting of eGFR is now part of the health landscape in Australia and many countries worldwide. There are well known limitations to this process and it is appropriate to keep working to address these issues. Some areas of new activity include the development of a new formula, the CKD-EPI formula; consideration of common reference intervals for serum creatinine; estimation of GFR for drug monitoring purposes and racial effects. To date there has also been little co-ordinated progress for the paediatric population with regard to creatinine measurement, reference intervals and GFR estimation. The joint working party of the Royal College of Pathologists of Australasia, the Australasian Association of Clinical Biochemists (AACB) and Kidney Health Australia plans to address these issues during 2010.

Serum vitamin A and E analysis: comparison of methods between laboratories enrolled in an external quality assurance programme

To survey laboratories enrolled in the Royal College of Pathologists of Australasia (RCPA) Chemical Pathology Quality Assurance Programme (QAP) for vitamin A and E testing to determine differences between methods of analysis. A detailed questionnaire covering the major aspects of serum vitamin A and E analysis was sent to all participating laboratories in 2007. Thirteen out of the 22 laboratories completed the questionnaire. Methods between laboratories showed a great deal of commonality. All respondents performed a liquid extraction step, which included the addition of an internal standard, followed by high-performance liquid chromatography (C18 columns with predominantly methanol-based mobile phases) with spectrophotometric detection. Major inter-laboratory differences were whether the sample was protected from light, the extraction solvents and ratios used, the drying down temperature used post-liquid extraction and choice of calibrator. The questionnaire highlighted discrete methodological differences between laboratories. These findings provide direction to enable the Vitamins Working Party of the Australasian Association of Clinical Biochemists to further investigate the dispersion in results between participants of the RCPA QAP vitamin programme.

Royal College of Pathologists of Australasia (RCPA) and Australasian Association of Clinical Biochemists (AACB) Position Statement on Impaired Fasting Glucose: Royal College of Pathologists of Australasia (RCPA) and Australasian Association of Clinica Biochemists (AACB)

Impaired fasting glucose (IFG) is defined as a fasting venous plasma glucose from 6.1 to 6.9 mmol/L inclusive. Impaired fasting glucose (IFG) is defined as a fasting venous plasma glucose from 6.1 to 6.9 mmol/L inclusive.

Desirable performance standards for HbA1c analysis – precision, accuracy and standardisation Consensus statement of the Australasian Association of Clinical Biochemists (AACB), the Australian Diabetes Society (ADS), the Royal College of Pathologists of Australasia (RCPA), Endocrine Society of Australia (ESA), and the Australian Diabetes Educators Association (ADEA)

HbA(1c) (glycohaemoglobin) is universally used in the ongoing monitoring of all patients with diabetes. There are many % HbA(1c) target control rating recommendations by national, regional and international expert bodies for diabetes patients and these are variable around the world. General patient target control ratings are currently most often recommended as either <6.5% or <7.0% HbA(1c), with <6.0% HbA(1c) stated for individual patients where clinically possible. This necessitates very precise HbA(1c) assays and the same patient values, irrespective of HbA(1c) method or area of the world. HbA(1c) targets recommended by major expert groups and published HbA(1c) assay precision (coefficient of variation, %CV) levels have been detailed. These have been compared with published biological variation levels and with calculated HbA(1c) error ranges at various HbA(1c) levels and %CV levels. In addition, these have been compared with the analytical precision necessary to differentiate between the upper limit of the normal range for HbA(1c) and targets recommended by expert groups for diabetes control. Intralaboratory analytical CVs of <2% are necessary and are achievable on automated HPLC analysers, and are supported on grounds of both clinical need and biological variation, as well as the need to differentiate the national, regional and international target recommendations from the upper limit of the normal range (<6.0% HbA(1c) level). Routine methods with tight long-term imprecision with CVs of <2% are recommended. International HbA(1c) targets essentially require that all HbA(1c) methods be precise, and have minimal standardisation bias and minimal methodological interferences in individual patients.

Sweat testing for cystic fibrosis: How good is your laboratory?

Sweat testing for cystic fibrosis: How good is your laboratory?

A discussion of cases in the 2001 RCPA-AQAP Chemical Pathology Case Report Comments Program

We present a descriptive analysis of the 10 case reports distributed in the Royal College of Pathologists of Australasia (RCPA) and the Australasian Association of Clinical Biochemists (AACB) Chemical Pathology Patient Report Comments Program to assess the quality of interpretative commenting in clinical biochemistry in 2001. Participants were asked to comment on a given set of biochemistry results attached with brief clinical details. All responses received were translated into key phrases and graphically presented on a histogram. An expert panel was asked to evaluate the appropriateness of the key phrases and to propose a suggested composite comment. While the majority of comments received were felt to be acceptable by the expert panel, some comments were felt to be inappropriate or misleading. As comments on laboratory reports may affect clinical management of patients, it is important that these comments reflect accepted practice and current guidelines. The Patient Report Comments Program may play an important role in continuing education and possibly in quality assurance of interpretative commenting.