Purity and quantity are measured on that lot by an independent American laboratory.
Reverse phase HPLC, run on the lot that ships to you.
The milligram figure is measured against the label, not copied from it.
One certificate per lot, open on the product page, marked pending while a lot is still in testing.
How pure it is, and how many milligrams are in the vial. Purity by reverse phase HPLC, quantity measured against the label. Both numbers are printed on the certificate with the laboratory, the lot number and the date. A lot still in testing is marked pending, and nothing is described as tested before the report exists.