The website is www.ngtc.gov.cn.

This is the so-called national inspection center.

There are laboratories in Beijing, Shanghai, Shenzhen and Panyu.

I haven't heard of this. A should also be a quality inspection station. Now there are many local quality inspection stations.

However, the most authoritative one is definitely the national inspection, because the national inspection participates in the formulation of the national standard and the appraisal standard is the strictest.

And be responsible for the annual market spot check.

However, according to the website you gave, they are accredited by ISO/IEC 17025 laboratory, so the certificate should be error-free.