Sample collection and analysis

Most blood and urine samples were collected at Sonic Healthcare Australia Pathology collection clinics or via a home visit. For more information, see the National Health Measures Survey methodology, 2022–24.

Qualified phlebotomists collected fasting and non-fasting blood samples from persons aged 12 years and over into four collection tubes:

• 1 x 8.5ml SST gel tube for serum analysis
• 1 x 8.5ml SST gel tube for validation tests
• 1 x 4ml EDTA (Ethylene Diamine Tetra-acetic Acid) tube for whole blood analysis
• 1 x 4ml Fluoride oxalate tube for blood plasma analysis.

The order of priority for collecting blood samples was the 8.5ml SST tubes, the 4ml EDTA tube, followed by the 4 ml Fluoride oxalate tube. While participants were encouraged to fast, fasting was optional. Sonic Healthcare Australia Pathology collectors recorded the fasting status, date, and time of each collection.

A spot urine sample was obtained from participants aged 5 years and over.

The ABS established a mechanism with Sonic Healthcare Australia Pathology ensuring that participants and/or their nominated health professional were notified by Sonic Healthcare Australia Pathology of critical or clinically significant test results.

All samples were analysed at a central Sonic Healthcare Australia Pathology laboratory at Douglass Hanly Moir Pathology (DHM) in Sydney, Australia on machines accredited by the National Association of Testing Authorities, with the exception of the iodine test which was conducted by Sullivan Nicolaides Pathology in Queensland. DHM conducted Internal Quality Control (IQC) analysis for all the instruments used to conduct analysis on the blood and urine samples.

Periodic analysis of External Quality Assurance (EQA) samples provided by the Royal College of Pathologists of Australasia (RCPA) was conducted at DHM, with results independently assessed against set targets. The ABS monitored the analysis and delivery of results through specific quality measures. The results from the IQC and EQA reports indicate that the accuracy and precision of instruments used to analyse samples fell within expected limits against set targets.

Quality measures provided by Sonic Healthcare Australia Pathology measured performance criteria such as turnaround time (TAT). The TAT was used to assess any adverse impacts to the blood and urine samples due to time delays from collection to analysis.

Quality measure targets included:

• TAT from collection to analysis of less than 72 hours
• TAT from first analysis to final report of less than 96 hours for blood samples and less than 120 hours for urine samples (to accommodate for iodine analyses)
• final and complete results provided to the ABS within 7 days
• less than 1% of results received to the ABS with missing information or results
• less than 1% of errors from total collection to be reissued
• less than 1% of collected samples with insufficient volumes or missing tubes
• all quality assurance reports (100%) results delivered to the ABS within the required range/standard.

All analyses were carried out according to standard operating procedures set by Sonic Healthcare Australia Pathology. All results were routinely checked by the dedicated quality control laboratory technicians and clinically significant results were notified to the laboratory pathologist. Method coefficient of variations were obtained by an appropriate IQC programme for each machine based on the measurement of biomarker concentrations around the clinical laboratory cut-offs.

Analytical control of the imprecision (variability) of results was monitored and maintained using a multi-layered quality assurance system comprising of:

• IQC processes
• participation in an EQA Program
• the periodic review of analytical variability for each test.

The ABS is satisfied with the quality assurance system used by Sonic Healthcare Australia Pathology to ensure the reliability of results.

IQC processes were conducted by the DHM laboratory to monitor the performance of the methods and machines used to analyse the blood and urine samples and identify any analytical errors.

An EQA system assesses the overall performance of the laboratory and conducts method comparisons between laboratory test results. Whilst conducting this assessment, the EQA authority can identify problems with certain methods.

DHM subscribes to the Quality Assurance Program (QAP) that is run by the RCPA (RCPA n.d.). During the testing period, DHM received blind samples of varying concentration from RCPA at regular frequencies throughout the calendar year. These samples were analysed with the results sent back to RCPA and compared against other laboratories across Australia and New Zealand.

RCPA distributes reports to all participating laboratories annually reporting mean values for test methods, inter-laboratory measurements of precision and details of laboratory bias. DHM provided their RCPA QAP reports to the ABS to ensure confidence in the analytical methods and machines used to analyse samples.

The vitamin D Standardization Program (VDSP) was established by the US National Institute of Health (NIH) Office of Dietary Supplements, in collaboration with the Centers for Disease Control and Prevention and the National Institute for Standards and Technology in 2010. The aim of the VDSP is to internationally standardise the vitamin D analytical method and test the international differences and similarities in serum vitamin D (25-hydroxyvitamin D [25(OH)D]) distributions (NIH 2024, n.d.). Sonic Healthcare Australia Pathology used the VDSP recommended method of analysis for vitamin D.

National Institute of Health Office of Dietary Supplements (NIH) (2024), Vitamin D, NIH website, accessed 20/02/2025.

National Institute of Health Office of Dietary Supplements (NIH) (n.d.), Office of Dietary Supplements Vitamin D Initiative 2004-2018, NIH, accessed 20/02/2025.

Royal College of Pathologists of Australasia (RCPA) (n.d.), RCPA Quality Assurance Programs, RCPA Quality Assurance Programs website, accessed 20/02/2025.