What are assay laboratory quality assurance materials in Australia?
Assay laboratory quality assurance materials in Australia are named preparations used so that instrument behaviour and method bias can be separated from the properties of the research sample. Each class answers a different question, so a method file should name them separately. System suitability asks whether resolution, mass accuracy, peak shape, or detector response meets a pre-agreed limit before sample results are accepted. A pooled or bracketed quality-control sample, placed at planned points in the sequence, asks whether that state held while the batch was acquired. A blank, prepared in the same diluent and container train, asks which signals come from solvent, vial, septum, or carry-over. A reference material or reference strain carries a characterised identity and, where supplied, an assigned value with an uncertainty.
Mass-spectrometry guidance treats system suitability and quality-control samples as different tools. Quality-control samples show whether the instrument state held across the batch, and whether individual features are repeatable enough to retain in the data set (PMID:29805336). A survey of liquid chromatography-mass spectrometry practitioners found uneven practice. Some groups routinely prepare pooled quality-control samples, process blanks, and internal standards, while others use a narrower set and record little rationale (PMID:33044703). An Australian research laboratory should write the minimum set into the method, including how each material is prepared, where it sits in the sequence, and which result causes the batch to be rejected or repeated.
On a peptide lot the classes keep the same meaning. The system-suitability run supports a claim that the system could separate the main component from closely eluting related substances. The blank supports a claim that a reported impurity was not introduced by the container or the diluent. Where a sequence-matched reference material exists, retention time and intact mass can be compared inside a stated window. A purity percentage does not identify which materials were used. The record that matters is whether resolution, mass accuracy, blank contribution, and retention behaviour met limits written before the sequence was started. A laboratory that files those limits beside the chromatogram can explain a failed batch without reconstructing the decision after the fact.
How should a laboratory qualify a reference strain or certified reference material?
Qualification is a documented decision that a named material is fit for one stated analytical use. It is not a restatement of the producer's catalogue line. Two published cases show the minimum depth a laboratory should expect, and the limits it should write down.
The 2024 World Health Organization reference strains of Neisseria gonorrhoeae were prepared for global quality assurance of laboratory investigations and supersede earlier WHO strains. Published characterisation includes phenotype, genetic markers, and a reference genome, so the panel is defined by data rather than by a short name (PMID:38889110). A receiving laboratory should record the panel generation, the strain identifiers in use, and which characterised attributes the method actually relies on. A superseded strain and a current strain should not share a control chart unless a bridge study states how the two generations compare. No procedure for obtaining, culturing, or propagating an organism is given here; the requirement is to file the generation and the characterisation scope.
Certified reference materials add a numerical layer. IAEA-465 is a certified reference material for radionuclides in Baltic Sea sediment, and its value to a receiving laboratory is the certificate pattern: defined matrix, named measurands, certified values, uncertainties, and traceability (PMID:39079350). A figure written only on a secondary label is not a certified value. Without a stated uncertainty, restrict the material to qualitative identity checks and do not use it to estimate bias. A sediment certificate does not cover a peptide solution, and a peptide reference standard does not cover an unrelated sequence. State the allowed use in the method: system suitability, identity comparison, or bias assessment.
The qualification note should list producer, code, lot, matrix, value and uncertainty if present, the certificate's storage statement, and the decision. File that note before the material is used on a research lot.
Where should system-suitability and pooled quality-control samples sit in the sequence?
Practical sequence design for assay laboratory quality assurance materials follows from the job of each preparation, not from habit. In untargeted mass-spectrometry guidance, the batch is treated as a time series. Early runs bring the column and source to a stable state and are not used as reportable data. System suitability is then judged against pre-set limits. Pooled quality-control samples, ideally prepared from the same matrix family as the study samples, are distributed through the batch so that drift is visible in the middle and at the end, not only at the opening (PMID:29805336). A blank after a high-level sample is more informative for carry-over than a blank run only at the start.
Repeatability is read from the quality-control replicates, not from a single chromatogram. Features or peaks that move beyond the laboratory's pre-set relative dispersion in those replicates are flagged as analytically unreliable, even if they look large in one sample. The 2018 guidance discusses this use of quality-control dispersion as a data-quality filter; it does not license a laboratory to invent a cutoff after seeing the data. Set the limit in the method before the sequence is acquired, and apply it to every batch of that method. Internal standards, where the chemistry allows them, track volume and ionisation changes. They do not replace the pooled quality-control sample, because an internal standard can be stable while the analyte of interest adsorbs to the vial or co-elutes with a contaminant.
Practitioner surveys show that this sequence is often simplified under time pressure (PMID:33044703). Simplification should be a documented deviation, not an unwritten shortcut. For peptide related-substance work, a minimum defensible sequence is conditioning runs, system suitability, a blank, the reference or retention marker if one is in use, the sample, a second blank or carry-over check, and a closing system-suitability or quality-control placement. If the closing check fails the pre-set limit, samples bracketed by the last passing check and the failure are not released.
When do material-based controls and a patient-based signal disagree?
Conventional internal quality-control materials are manufactured preparations at assigned levels. They can still miss a shift. The material may not commute with routine samples, so a bias that appears in samples does not appear in the control. Or the shift may be smaller than the rule applied to a single control level, yet visible when many results are viewed together. Patient-based real-time quality control was described to address that gap. It applies moving statistics to the stream of sample results and raises an alarm when the stream departs from the recent baseline (PMID:32486872). Block size, truncation of extreme values, and control limits have to be set against the analytical variation of that assay, or the alarm rate becomes either noise or a missed shift. Published implementation work treats the patient-based signal as a complement to internal quality-control materials, not as a reason to drop them.
A research peptide laboratory usually holds a short series of lot results rather than a long consecutive result stream, so a moving-statistic alarm designed for high-volume testing cannot be copied across without a stated sample size. The transferable design rule is narrower: do not rely on one quality-assurance material at one level. Pair it with an independent observation, such as a second level, a blank, an orthogonal mass measurement, or a stable monitor peptide carried in the sequence. If those observations disagree, the lot is not averaged into a pass.
Commutability is the other reason materials and samples diverge. Work on faecal immunochemical tests for haemoglobin shows that numerical results are method-dependent, and that a quality-assurance material which does not behave like the samples will make a laboratory look biased when the mismatch sits in the material-method pair (PMID:33571484). The same logic applies when a peptide laboratory adopts a reference standard dissolved in a different diluent, or a different counter-ion, from the lots under test. The standard may still be valid for identity. It is a weak bias control until the matrix difference is assessed and written into the method. A value copied onto a worksheet without the matrix and the uncertainty is not a control limit.
How is analytical validity shown, and what belongs in an Australian lot file?
Analytical validity is not a purity percentage. It is a demonstrated property of a method: using characterised reference materials, the method detects a defined difference, and it does not report that difference when the reference material lacks it. An inter-laboratory evaluation of circulating tumour DNA sequencing assays used reference samples that carried known variants at known relative amounts, and compared laboratories on whether those variants were found or missed, including false-positive calls (PMID:33846644). The paper is cited only as an analytical-design example of how known composition in a reference sample is used to score true detection and false calls. Identity and related-substance methods for peptides should likewise be challenged with materials that contain the expected mass or sequence and, where possible, a known deletion, truncation, or mass-shift analogue. A single statement that the main peak was present, without the reference-material level and without a record of false calls, is an incomplete validity claim.
A published quality-control guideline separates release into attributes, each with a method and an acceptance statement: identity, contaminant status, genomic integrity, and the documentation that ties them to the lot (PMID:30205750). Only the documentation logic is carried across to research peptide records. For a peptide lot the parallel list is analytical: intact mass or sequence evidence, chromatographic purity with the integration rules stated, related substances above the reporting threshold, and any counter-ion or residual-solvent result the specification includes. Attributes not tested should be marked as not tested. A blank cell is later misread as a pass. Recording the integration rules beside the purity figure lets a later reviewer see whether a shoulder was excluded, and whether that exclusion was allowed by the method before the chromatogram was inspected.
An Australian laboratory accepting a peptide lot, or the quality-assurance material used to test it, should be able to join four identifiers without a phone call: the vial label, the certificate lot, the sequence sample name, and the qualification note for each quality-assurance material in that sequence. Shipping or stock location does not replace those identifiers. Ask which reference or system-suitability material was run, whether its certificate scope covers the method, and what happens when the closing check fails. A laboratory that can answer from the lot file is in a stronger position than one that can quote only a purity figure.
Frequently asked questions
Are assay laboratory quality assurance materials the same as a certificate of analysis?
No. A certificate of analysis reports results for a specific lot against a specification. Quality-assurance materials are the preparations used to show that the method generating those results was under control. A complete lot file cites both: the certificate for the research material, and the identity and lot numbers of the system-suitability, blank, and reference materials run with it. A purity figure without that cross-reference does not show which analytical state produced the figure.
Does a high chromatographic purity percentage replace system suitability?
No. Area-percent purity describes the peak composition of that run. System suitability describes whether the method could have separated the main component from a named related substance on that day. A run can report a high area percent and still fail a resolution or mass-accuracy limit. Guidance for mass-spectrometry assays treats the suitability check and the quality-control sample as separate decisions (PMID:29805336). Read both lines on the batch record before comparing lots.
What should a certified reference material certificate contain?
At minimum, the matrix, the measurands, the certified or assigned values, the uncertainties, and a traceability statement. IAEA-465 illustrates that structure for a sediment matrix (PMID:39079350). If uncertainty is absent, limit the material to qualitative identity checks and do not use it to estimate bias. Record the lot identifier and confirm that the laboratory samples fall inside the certificate scope. A peptide solution is not inside the scope of a sediment material, and the reverse is also true.
Can patient-based real-time quality control replace internal quality-control materials?
No. Patient-based real-time quality control uses the stream of sample results to detect shift or bias. Implementation studies treat it as a complement to conventional internal quality-control materials, not a replacement (PMID:32486872). It needs a sufficient result stream, a tuned block size, and limits set against analytical variation. A research peptide laboratory with few lots each week usually lacks that stream. The transferable practice is to keep an independent check beside any single-level control material.
How should superseded reference panels be handled in an assay laboratory?
Record the generation in use. The 2024 WHO Neisseria gonorrhoeae reference strains were characterised phenotypically, genetically, and by reference genome, and they supersede earlier WHO strains (PMID:38889110). Do not plot a superseded strain and a current strain on one control chart unless a bridge study documents the comparison. A change of panel can otherwise be misread as assay drift. This is a documentation rule. It is not guidance on obtaining or culturing any organism.
How should blanks and carry-over checks be read in a peptide related-substance sequence?
A blank prepared in the same diluent and container train shows which signals come from solvent, vial, or septum rather than from the research lot. A blank placed after a high-level sample is more informative for carry-over than a blank run only at the start, because residual analyte on the injector or column appears in the following injection. If a reported impurity is also present in the matched blank at a comparable area, the impurity should not be assigned to the lot until the container train is investigated and the sequence is repeated. System suitability does not answer that question, because a suitability mix can meet resolution limits while a contaminated diluent still contributes peaks. The batch record should store the blank chromatogram beside the sample chromatogram, with the same integration rules, so a later reviewer can see whether a reported related substance was already present in the blank.
References
- PMID:29805336 — Guidelines and considerations for the use of system suitability and quality control samples in mass spectrometry assays applied in untargeted clinical metabolomic studies — Metabolomics — 2018
- PMID:33044703 — Dissemination and analysis of the quality assurance (QA) and quality control (QC) practices of LC-MS based untargeted metabolomics practitioners — Metabolomics — 2020
- PMID:38889110 — The novel 2024 WHO Neisseria gonorrhoeae reference strains for global quality assurance of laboratory investigations and superseded WHO N. gonorrhoeae reference strains-phenotypic, genetic and reference genome characterization — J Antimicrob Chemother — 2024
- PMID:39079350 — A new certified reference material IAEA-465 for radionuclides in Baltic Sea sediment — J Environ Radioact — 2024
- PMID:32486872 — Implementation of patient-based real-time quality control — Crit Rev Clin Lab Sci — 2020
- PMID:33571484 — Faecal immunochemical tests for haemoglobin: Analytical challenges and potential solutions — Clin Chim Acta — 2021
- PMID:33846644 — Evaluating the analytical validity of circulating tumor DNA sequencing assays for precision oncology — Nat Biotechnol — 2021
- PMID:30205750 — Quality control guidelines for clinical-grade human induced pluripotent stem cell lines — Regen Med — 2018
Research use only
This article is provided for laboratory research and educational purposes only. Products referenced are not for human or veterinary use. ClaraScience makes no therapeutic, medical, or efficacy claims, and nothing here constitutes medical advice.
