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Quality inspection in China: what an inspection agent checks

What a quality inspection agent in China does, the four inspection types and when to book each, what a man day costs, and how AQL sampling works.

Guide Buying and Sourcing Updated The ChinaBridge desk 15 min read
An inspector in a factory with a clipboard and a tape measure, opened cartons on a table, checking a product against a sample

Quality Inspection Agent in China: Cost, AQL & Pre-Shipment Inspection for Nigerian Importers

A quality inspection agent in China checks your goods at the factory before they are shipped to Nigeria.

The inspector goes to the supplier, selects products from the production lot, checks them against your approved specification or sample, tests important functions, counts cartons, photographs defects and sends you a written report.

For a Nigerian importer, the timing is the important part.

If the inspection happens before you pay the final balance and before the goods leave China, you can still ask the factory to repair, replace or remake defective products.

Once the goods have arrived in Lagos, Port Harcourt, Kano or anywhere else in Nigeria, correcting a manufacturing problem becomes much more expensive.

This guide explains:

What does a quality inspection agent in China do? #

The inspector works from the requirements you provide.

That may include:

Without a clear specification, the inspector has very little to inspect against.

You cannot simply tell an inspector:

“Check whether the quality is good.”

You need to define what good means.

What does a pre-shipment inspection check? #

The exact checklist depends on the product, but a normal inspection usually covers several areas.

Quantity #

The inspector confirms:

This is compared with your purchase order.

Workmanship #

Products are checked for visible manufacturing defects.

Defects are normally classified as:

For clothing, that may mean checking stitching, stains, loose threads and measurements.

For electronics, it may include scratches, loose components or defective assembly.

For furniture, it may include finishing, alignment and construction.

Product specification #

The inspector checks whether production matches what you ordered.

Depending on the product, this can include:

If you approved a sample, the production goods can also be compared with that sample.

Our samples from China to Nigeria guide explains why the approved sample should become part of your production reference.

Function #

Where practical, the inspector tests whether the product works.

Examples include:

The exact functional test should be agreed before the inspector visits.

Packaging #

Packaging matters because your goods still have a long journey to Nigeria.

The inspector can check:

Good products can still arrive damaged if the packaging is poor.

On-site tests #

Depending on the product, you may also request simple tests such as:

But do not confuse factory inspection with laboratory testing.

Chemical composition, electrical safety certification, battery performance analysis, material composition and other technical tests may require laboratory equipment and additional fees.

The four main types of quality inspection in China #

Different inspections happen at different stages of production.

You do not necessarily need all four.

1. Pre-production or initial production inspection #

This happens before or around the beginning of manufacturing.

The inspector can check:

This is particularly useful for:

If you ordered 5,000 shirts using 220 GSM fabric, discovering that the factory bought the wrong fabric before cutting begins is much cheaper than discovering it after 5,000 shirts have been sewn.

2. During production inspection #

A during-production inspection is often called DUPRO.

It happens while manufacturing is underway.

Depending on the inspection company and product, it can be performed when roughly 20% to 80% of production has been completed.

It is useful when:

The advantage is simple.

If a defect is discovered after 500 pieces have been made, the factory may still be able to correct the remaining 4,500.

If you wait until everything is finished, the problem is much bigger.

3. Pre-shipment inspection #

For most Nigerian importers, this is the most important inspection.

A Pre-Shipment Inspection — PSI is normally performed when production is substantially complete, commonly around 80% to 100% finished and packed.

The inspector randomly selects goods and checks them against your requirements.

A PSI normally covers:

If you are paying a deposit and balance arrangement such as:

30% deposit + 70% balance

the inspection should normally happen before releasing the final balance, provided that this was agreed with the supplier.

That gives you commercial leverage while the goods are still at the factory.

4. Container loading check #

A Container Loading Check — CLC happens when the goods are being loaded for shipment.

The inspector can verify:

It can also document how the cargo was loaded.

A loading inspection is especially useful for:

A pre-shipment inspection checks the goods.

A container loading check confirms what actually goes into the container.

They solve different problems.

Our Chinese supplier scams guide explains why buyers should maintain control of both the supplier and shipment records.

If you can afford only one inspection #

Book the pre-shipment inspection.

For most ordinary commercial orders, it gives you the best opportunity to identify:

before the goods leave China.

For a large custom production run, add a during-production inspection.

For a valuable full container, consider adding a loading check.

How does AQL inspection work? #

Most professional inspection companies do not inspect every unit in a large order.

They use statistical sampling.

One widely used system is:

ISO 2859-1 / ANSI/ASQ Z1.4

The system determines how many units should be randomly inspected based on:

A commonly used setting for ordinary consumer goods is:

General Inspection Level II

But the correct setting depends on your product and risk.

What does AQL mean? #

AQL means Acceptance Quality Limit.

It is used within the statistical sampling plan to determine how many defects can be found in the inspection sample before the lot reaches the rejection point.

It does not simply mean:

“AQL 2.5 allows 2.5% defective goods.”

That is a common misunderstanding.

The actual acceptance and rejection numbers come from the sampling tables.

Example: 5,000-piece order #

Suppose you order:

5,000 pieces

and use:

General Inspection Level II

Under the standard sampling table, the inspector would normally select a sample of around:

200 pieces

from different cartons and locations within the lot.

The inspector then records defects according to their classification.

The allowed acceptance and rejection numbers depend on the AQL selected for each defect category.

Critical, major and minor defects #

Critical defect #

A problem that can create a serious safety risk, regulatory problem or make the product dangerous.

Typical tolerance:

Very low or zero

depending on the product and agreement.

Major defect #

A defect that substantially affects:

Examples:

Minor defect #

A smaller problem that does not normally prevent use but is still below the agreed standard.

Examples might include:

The defect classification should be agreed before inspection.

What AQL should Nigerian importers use? #

There is no single correct AQL for every product.

For ordinary consumer products, you will often see inspection plans using figures such as:

But those numbers should not simply be copied into every order.

A medical product, children's product, electrical appliance and fashion accessory do not carry the same level of risk.

For higher-risk products, use stricter quality requirements.

Put the inspection standard in writing #

Do not introduce AQL after production is complete.

Agree it before manufacturing starts.

Your purchase order, contract or proforma invoice should make clear:

Then both sides know the rules before money is committed.

How much does a quality inspection in China cost? #

Most third-party inspection companies price routine inspections by the man-day.

One man-day generally means one inspector working approximately one normal working day at the factory.

For standard consumer-goods inspections in China, a realistic budget is often around:

US$250 to US$350 per man-day

depending on the provider and location.

For example, one established inspection company currently publicly lists approximately:

US$268 per man-day

in its main China coverage regions and:

US$298 per man-day

elsewhere.

Larger international firms such as:

may quote according to:

Ask for a quote using the actual factory address and product description.

When does an inspection cost more? #

The price may increase when:

Do not compare inspection companies only by the headline daily rate.

Compare what the inspection actually includes.

Is inspection worth the cost? #

Consider a Nigerian buyer importing goods worth:

US$15,000

A US$250–$350 inspection represents only a small percentage of the product value.

If it discovers that:

before shipment, the inspection can cost far less than correcting the same problem in Nigeria.

The bigger the financial consequence of a defective order, the easier the inspection cost is to justify.

Who should inspect your goods in China? #

You generally have three options.

International inspection company #

Examples include:

Advantages can include:

This may be useful when your customer, bank or organisation requires documentation from an established independent company.

Independent Chinese inspection company #

China has many local quality-control companies.

They may offer lower prices and strong local coverage.

Before using one, check:

Cheap inspection is not useful if the report is unreliable.

Your sourcing agent #

A sourcing agent can also inspect goods if the agent has competent staff and works for you, not for the supplier.

For ordinary products, this can be practical.

For technical goods, high-value orders or disputes, an independent third-party inspection company may provide stronger separation between sourcing and quality control.

Our China sourcing agent in Nigeria guide explains how sourcing agents work and how to check who they represent.

Do not let the factory inspect itself #

The factory should have its own quality-control process.

But factory QC and independent buyer inspection are different things.

The factory's staff work for the factory.

Your independent inspector works for you.

Supplier photographs and videos can be useful for production updates.

They are not the same as an independent inspection where the inspector chooses random cartons and samples.

How to book a quality inspection in China #

Step 1: Prepare your specification #

Send the inspector:

Step 2: Get the factory details #

You normally need:

Make sure you know which factory actually produced the goods.

Our Chinese supplier checking guide explains why the company's real production location matters.

Step 3: Book the correct inspection date #

For pre-shipment inspection, book when enough of the order will be finished and packed for proper random sampling.

Do not let the factory arrange the inspection before there is enough finished stock.

Step 4: Tell the supplier #

Third-party inspection should not be a surprise attack.

The supplier should know from the beginning that the order will be inspected.

Experienced export factories are used to buyer inspections.

Step 5: Read the report #

Do not look only at:

PASS

or:

FAIL

Read the photographs and findings.

Check:

You are still the buyer.

The report helps you make the commercial decision.

Step 6: Resolve failures before final payment #

If the inspection identifies unacceptable defects, discuss:

before releasing the final balance.

If your agreement says the supplier pays for reinspection after a failed inspection, enforce that term.

What if the inspection fails? #

A failed inspection does not automatically mean the entire order must be cancelled.

First identify the problem.

For example:

20 cartons have the wrong labels

may be easy to correct.

Every electrical product has the wrong voltage

is much more serious.

Possible responses include:

The response depends on the defect and your written agreement.

Inspection does not replace laboratory testing #

This distinction matters.

A normal factory inspection may tell you:

The cable is 2 metres long.

It may not be able to prove:

The copper content meets a particular chemical standard.

An inspector can see that a fabric label says:

100% cotton.

A laboratory may be needed to prove its fibre composition.

Laboratory testing may be required for:

Ask what can actually be tested on-site.

Inspection does not replace Nigerian import compliance #

A Chinese quality inspection checks whether the goods match your order.

It does not automatically prove that the product meets every Nigerian regulatory requirement.

For regulated imports, you may separately need:

depending on what you are importing.

Quality control and regulatory compliance are connected, but they are not the same thing.

Common inspection mistakes Nigerian importers make #

Inspecting after paying the balance #

This removes much of your commercial leverage.

Where your payment terms allow it, inspect before releasing the final payment.

Giving the inspector no specification #

The inspector cannot guess what you intended to buy.

Write everything down before production.

Using only supplier photographs #

Photos are useful.

Independent random sampling is better.

Inspecting only the first order #

A supplier performing well once does not mean every future shipment should automatically go unchecked.

As the supplier builds a reliable history, you can adjust inspection frequency based on risk and performance.

Using an inspector chosen by the factory without checking them #

If independence matters, appoint the inspection company yourself.

Skipping reinspection after a failed report #

If the factory says:

“We fixed everything.”

verify that the correction was actually made before paying.

Forgetting container loading #

For valuable full-container shipments, a loading check gives you a record of what was actually placed inside the container and the final seal number.

Quality inspection checklist for Nigerian importers #

Before production:

Before inspection:

After inspection:

Before shipment:

Do you need a quality inspection agent in China? #

You probably do not need a full independent inspection for every tiny sample order.

But inspection becomes increasingly sensible when:

The question is not:

“Can I save US$300 by skipping inspection?”

The better question is:

“What would it cost me if this order arrives wrong?”

A quality inspection gives you information at the point where that information is still useful.

The goods are still in China.

The supplier can still correct them.

And, if your payment terms were structured properly, you may still control part of the payment.

That is why pre-shipment inspection is one of the simplest forms of risk control available to Nigerian importers buying directly from China.

Before booking one, make sure you have an approved product specification or sample.

An inspection can only check the factory against the standard you gave it.

First published 27 Sep 2026. Last checked 27 Sep 2026 by The ChinaBridge desk. Something here out of date? Tell us in the comments and we will fix it.

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