What is a certificate of analysis (COA)?

Buyers of chemicals, coatings, ingredients, plastics and metals often ask for a COA before they accept a delivery. It is the proof that what arrived is what was ordered.

Why a COA matters

A product can be sold under one name and still vary from batch to batch. A buyer who runs the material through a production line cannot afford surprises. The COA tells them, before they use it, that the batch was tested and where each result sits against the limits.

For the seller, it is also a record. If a customer questions a batch months later, the COA and the lot number let you see what was tested and what the results were.

What a COA usually contains

The layout differs by industry and company, but most certificates include:

• The product name, grade and code
• The batch or lot number, and often the manufacturing date
• The tests performed, with the method used for each
• The specification limit for each test
• The actual result for that batch
• The name or signature of whoever released it, and the issue date

Some industries add extra fields, such as an expiry or retest date. Which fields are expected is usually agreed between buyer and seller, or set by the buyer's own quality requirements.

COA versus technical data sheet

The two are often confused. A technical data sheet describes the product in general: typical properties and how to use it. A COA describes one batch: what was measured on that lot. One is the same for every customer, the other is specific to the shipment.

An example from product sales

Say a coatings manufacturer ships 10 drums of a resin to a customer. The customer's receiving team asks for the COA for lot 2310-A before releasing the drums to production. The rep finds the certificate, sends it by email, and the customer's quality team checks it against their own limits. If the customer later reports a problem, the lot number on the COA connects the complaint to the batch.

Related terms

• Technical data sheet: the general product description, not tied to a batch.
• Safety data sheet: the hazard and handling document for a product.
• Sample management: samples are often sent with a COA for the sample lot.
• Sales order: where the lot and delivery details can be recorded.

How PromptLab handles it

The testing and the certificate come from your lab or quality team. PromptLab keeps the sales side organised. Sample requests are tracked with a status and linked to the account and deal. Quotes and sales orders sit on the same account, and you can upload the COA to the account's Files tab, next to the email thread that carried it.

Frequently asked questions

What does COA stand for?

COA stands for certificate of analysis. It is a document with the test results for one batch of a product.

Who issues a certificate of analysis?

Usually the manufacturer, or the supplier that tested the batch. Some buyers also ask for a certificate from an independent laboratory.

Is a COA the same as a certificate of conformity?

No. A COA reports the measured results for one batch. A certificate of conformity is a statement that the product meets a stated specification or standard, and it usually does not list test results. Some suppliers issue both, or combine them on one document.

Is a COA needed for every shipment?

It depends on the customer and the product. Many buyers ask for one with every batch, others only on request. Agree it with the customer and write it into your terms.

Can a COA be used for several batches?

Normally not. A COA belongs to one batch or lot, so each new batch has its own certificate.