Analytical Testing Methods
Read a test result by asking what was measured, on which sample, by which procedure and against which criterion. HPLC, mass spectrometry, assay and microbiological tests answer different questions; the method name alone is not the result.
Request lot test recordsMatch the method to the question
| Method or test | What the result can address | Limitation to keep beside it |
|---|---|---|
| RP-HPLC with area normalisation | The relative integrated detector response of peaks included in the calculation | An uncorrected area percentage is not automatically a mass fraction; response and integration affect the result. [A5] |
| Identity-focused mass spectrometry | Whether observed mass-related evidence supports the proposed identity | An intact-mass match alone does not distinguish every structure or sequence with that mass. Read the identification procedure and its selectivity. [A2] |
| Quantitative assay | The amount or concentration of a defined analyte on the stated calibration and reporting basis | A quantitative result needs a procedure suited to that measurement; an identity test alone does not supply it. [A2] |
| Water-content determination | Water measured by the stated procedure, such as Karl Fischer titration | The value is separate from chromatographic purity and from residual-solvent content. [A4] |
| Residual-solvent analysis | The named solvents covered by the method, for example a gas-chromatographic procedure | Coverage is limited to the stated analytes and method capability; it is not a claim that every possible solvent is absent. [A4] |
For chromatography, begin with HPLC explained and reading a chromatogram. For identification, see mass-spectrometry evidence and why a purity percentage does not prove identity.
Assay, water content and residual solvents explains their different denominators and units. Keep those distinctions when interpreting the 99%+ purity claim.
Keep microbiological results separate
Sterility testing examines samples for microbial growth under the test conditions. Bioburden testing estimates recoverable microorganisms under a defined procedure. Bacterial endotoxin testing addresses a different attribute; it does not count viable organisms. These are separate analytical questions with their own sampling and method-suitability considerations. [A6] [A7]
A result applies within the scope of the sample and procedure. “No growth” does not provide an endotoxin measurement, and an endotoxin result does not establish sterility. For endotoxin methods, sensitivity and inhibition or enhancement are relevant to interpretation. [A7]
The sterility, endotoxin and bioburden guide explains the distinctions. No microbiological panel, universal acceptance limit or suitability for human or veterinary use is established by this overview.
Read the procedure behind the label
A method family is a starting point. For a reported result, look for the method reference or version, the sample identification, the reporting basis and the applicable criterion. Supporting information may include a chromatogram, spectrum, reference comparison or calibration record, depending on the question.
ICH Q2(R2) treats specificity or selectivity as the ability to measure the intended attribute despite relevant interferences. Where one procedure lacks sufficient discrimination, complementary procedures may be needed. Those validation principles do not confirm the performance of a particular supplier method. [A2]
| Illustrative document entry | What is established | What remains to be requested |
|---|---|---|
| “Tested by HPLC” with no result | The document makes a method claim. | Sample and lot connection, procedure, result and reporting basis. |
| A lot-linked result with units and a method reference | An observation is reported for the identified sample. | The applicable criterion and any supporting data needed to interpret the observation. |
| A result compared with a stated criterion | The comparison can be examined within that scope. | The recorded material decision and any unresolved findings. |
These are fictional document situations, not descriptions of completed Knockout Labs tests. Missing information is an evidence gap; it is not a measured failure or a passing result.
Confirm the programme for your lot
Request the available documents through the batch-report library. Specify the product, exact lot and the attribute you need to assess. Ask which tests were performed, which are pending or not included, and whether the sample was taken from bulk material or the supplied presentation.
Use laboratory verification to examine the named laboratory and relevant scope. A laboratory credential does not supply a missing lot result. Keep the report with the applicable specification and release decision; the quality hub provides the routes between them.
References
These sources explain analytical and documentation principles. Pharmaceutical and device guidance has its own scope; citation does not establish supplier compliance, an actual testing programme or a lot result. Manufacturer documentation does not identify a Knockout Labs supplier.
- [A2] ICH Q2(R2): Validation of Analytical Procedures. FDA / ICH. March 2024. Sections 3.1–3.2: specificity, identification, assay and response.
- [A4] Quality Control of Amino Acids & Peptides: A Guide. Bachem. Undated web guide. Product content; net peptide content.
- [A5] OpenLab CDS: Data Analysis Reference Guide. Agilent. February 2019, revision C. Printed pages 137–138: Area% and calibrated quantitation.
- [A6] Pharmaceutical Microbiology Manual, ORA.007, revision 02. FDA. 25 August 2020. Chapters 2, 3 and 8: microbial enumeration, sterility and bioburden.
- [A7] Pyrogen and Endotoxins Testing: Questions and Answers, edition 2. FDA. March 2026. Introduction and question 6: test scope, sensitivity and interference.
Sources accessed 23 October 2026. Request outlines, comparison tables and illustrative document situations are original editorial synthesis.