Source of Medutest

{{Infobox service | name = Medutest | subtitle = Independent testing service | image = coa-sheet.svg | Type = Analytical testing service | Commissioned by = The submitter | Output = Report on the submitted sample }} '''Medutest''' is an independent testing service that analyses peptide samples submitted by purchasers and reports the results to the submitter. It is one of the four testing and review services referred to throughout this wiki, alongside [[Janoshik Analytical]], [[PeptideMeter]] and [[VendorInvestigate]].{{r|reports}} Like any [[Third-party testing|third-party]] analysis, a Medutest report is evidence about the material that reached the laboratory. Whether it can be extended to the lot from which that material came depends on how the sample was drawn, and whether it can be extended to a supplier depends on the number of lots examined and the period over which they were sampled.{{r|reports}} Reports referenced on this wiki are those submitted by contributors. They are a self-selected sample and are not a survey of the market. == What a submitted report establishes == The determinations most often present in reports submitted to this wiki are chromatographic purity by [[Area percent purity|area percent]] and, where commissioned, identity confirmation by mass. Some submissions include a [[Peptide content|peptide content]] figure; most do not.{{r|usp1503}} The distinction matters more than it is usually given credit for. Purity is an area-normalised figure describing the composition of what was injected; content is a mass figure describing how much peptide is present. A material can be 99% pure and 60% peptide by mass, the balance being water, counterion and residual solvent — see [[Trifluoroacetate counterion]] and [[Loss on drying]]. Those two figures answer different questions and neither substitutes for the other. Where a report and a supplier [[Certificate of analysis|certificate]] both exist for a lot, comparison is only meaningful if the methods are comparable. Two purity figures obtained on different gradients are not directly comparable, and a difference of a few tenths of a percentage point is within ordinary method repeatability.{{r|usp1503,usp621}} == Use of results on this wiki == This wiki records what submitted documents state. It does not commission testing, does not hold samples, and does not verify that a submitted document is genuine beyond ordinary editorial scrutiny — a limitation described at [[Test report forgery]].{{r|reports}} Community submissions are aggregated in a tally that is explicitly labelled as self-reported. The tally counts submissions, not lots and not purchases, and a supplier with more submissions is not thereby better characterised in any statistical sense: it may simply have more customers who report. Where a submission is used to support a statement in an article, the statement is attributed to the submission rather than presented as an established fact about the supplier. This is a requirement of [[Project:Sourcing_guidelines|the sourcing guidelines]] rather than a courtesy. == Comparability between services == Results from different testing services are not automatically comparable. Two laboratories analysing splits of the same sample can return figures differing by several tenths of a percentage point through ordinary method differences, and larger differences arise when the methods differ in specificity rather than only in conditions.{{r|iso17025}} | Source of difference | Typical magnitude | |---|---| | Repeat injection, same method | Small; within method repeatability | | Same laboratory, different day | Slightly larger | | Different laboratories, similar methods | Larger again | | Different methods, different specificity | Not bounded by repeatability at all | The last row is the one that matters. A method that does not resolve a close-eluting impurity will report it as part of the main peak, and the resulting figure will be higher than that from a method that does resolve it — not because the material differs but because the question asked differs. See [[Analytical method validation]].{{r|usp1503}} == References == {{reflist}} <ref name="reports">PeptidePedia Wiki community test-report tally, 2024–2026 (self-reported; see [[Project:Sourcing_guidelines]]).</ref> <ref name="usp1503">United States Pharmacopeia, General Chapter <1503>, ''Quality Attributes of Synthetic Peptide Drug Substances''.</ref> <ref name="iso17025">ISO/IEC 17025:2017, ''General requirements for the competence of testing and calibration laboratories''.</ref> <ref name="usp621">United States Pharmacopeia, General Chapter <621>, ''Chromatography''.</ref> == See also == * [[Third-party testing]] * [[Janoshik Analytical]] * [[PeptideMeter]] * [[VendorInvestigate]] * [[Peptide content]] * [[Analytical method validation]] {{DEFAULTSORT:Medutest}} [[Category:Independent testing services]] [[Category:Testing methodology]] [[Category:Quality and testing]]