How to Read a COA | Calibr Bio Labs

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Three results. Three different questions.

IDENTITY

What is it?

Evidence that the sample matches the expected compound.

PURITY

How pure is it?

The target component relative to other components detected by the reported method.

QUANTITY

How much is there?

A separately measured amount or content, reported with its own units and method.

Read each result on its own terms. A purity percentage does not answer all three questions.

Match the sample and lot

Compare the report’s product or sample name, lot or batch, and tested strength with the vial label and available records. A matching product name alone is not enough to connect a report to your material.

Product or sample: The compound or formulation identified in the report.
Lot or batch: The identifier connecting the submitted material to its records.
Tested strength or size: The sample described by the laboratory, which may differ from other catalog options.

A report for one sample does not automatically cover every vial, offered strength, or later batch. If a lot is missing or the identifiers do not match, ask Calibr for clarification.

Verify the original report

Identify the issuing laboratory, report or task number, analysis date, and document version. When the laboratory provides a verification portal, open the stored original using the report’s verification details and compare it with the copy you received.

Calibr’s library distinguishes supplier documents from Calibr submissions. Check who submitted the sample. A verified report confirms the laboratory’s record; it does not independently establish how representative that sample is of other material.

Reference: Janoshik’s report verification guidance ↗

Understand the purity result

Peptide purity is commonly reported using high-performance liquid chromatography (HPLC). With UV detection, the assigned target peak’s area is compared with the total integrated peak area under that method.

Look for the analytical method, chromatogram, and peak table when provided. A percentage without its method leaves important context missing.

HPLC purity is not the vial’s peptide weight.

A 99% HPLC result does not mean that 99% of the powder’s total weight is the target peptide. Water, counterions, and residual solvents require other measurements.

Reference: Bachem’s peptide quality control guide ↗

Check identity separately

Mass spectrometry (MS) is often used to compare observed molecular mass with the expected value. Read the laboratory’s identity conclusion and method, including any reported comparison or tolerance.

A matching molecular mass supports identity under the reported analysis. It should not be treated as complete sequence verification unless the report actually includes an appropriate sequencing analysis. A purity result is a separate measurement.

Reference: GenScript’s peptide QC report guide ↗

Find the amount or content

Look for a separate result labeled amount, assay, content, or quantity. Check the units and whether the result describes the submitted sample, a vial, or a measured portion.

Amount, such as mg: A mass result. Check what was measured and the laboratory’s calculation basis.
Net peptide content, %: The percentage of sample mass that is peptidic material, including peptide impurities. Moisture and counterions are non-peptidic material. This is distinct from the target peptide’s HPLC purity.
Catalog strength: The product’s stated amount. Do not assume it is a measured result unless the report establishes that connection.

If quantity is not reported, record it as unreported. Do not infer a measured amount from the purity percentage alone.

Reference: Bachem’s distinction between purity and net peptide content ↗

Know the report’s limits

Count a test as documented only when its result and method are explicitly reported. Identity, purity, quantity, microbial testing, and endotoxin testing answer different questions. A purity percentage alone does not establish sterility or endotoxin status.

Read any qualifications, missing results, sample limitations, and laboratory comments. A listed specification or acceptance limit is different from the sample’s actual result. If the report only says “passes,” ask which test and limit that conclusion refers to.

Reference: Janoshik’s separately offered analytical tests ↗

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Your COA review checklist

The sample name and lot or batch can be linked to the material you are reviewing.
The tested sample strength or size is clear; coverage of other strengths is not assumed.
The issuing laboratory, report number, and analysis date are identifiable.
The original report has been checked using the laboratory’s verification process, when available.
Purity, identity, and quantity are read as separate results, with their methods and units.
Missing tests or unclear identifiers have been raised with the supplier or laboratory.

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Sources and further reading

This guide draws on published analytical documentation. The linked organizations are independent sources and do not endorse Calibr Bio Labs.

Educational information for laboratory research documentation. This guide does not change the intended use of any product. All Calibr materials are for research use only and are not intended for human or veterinary use.