The phrase "a certain test" is correct and usable in written English.
It can be used when referring to a specific test that is not named or when the speaker assumes the listener knows which test is being discussed.
Example: "Before we proceed, I need to ensure that you have passed a certain test required for this position."
Alternatives: "a specific test" or "a particular test".
She is so fearful of failing a certain test that she repeats a trick she tried before.
But a final answer remained elusive, a certain test of the fatalism that Mr. Bush had expressed at the beginning of what was clearly his longest day.
A billing clerk will see that a patient had a certain test, but will no longer see the test results or anything else in the patient's records.
Still, the results suggest that focusing on what patients want — a certain test, a specific drug — may mean they get less of what they actually need.
He believes this is becoming more important because physicians are being assessed on whether they gave the right medicine to a patient, or remembered to order a certain test.
Children suffering from neural disorders affecting speech and comprehension exhibit certain patterns when performing a certain test, essentially narrating a series of pictures.
Let n be a total number of test images associated with a certain tested model.
Drug metabolic stability tests are conducted to determine the rate of decrease in drug levels within a certain testing system.
We also considered it essential to fix the health gain associated with a certain test-frequency combination, as results from a pilot study showed that patients had difficulties understanding choices in which health gain was counter-intuitively.
As the input power increased, surface temperature increased, and at a certain point, test surface temperature increased rapidly and the test sample was burning out.
Fluoranthene is an important volatile PAH because it occurs at high concentrations in ambient air and because it is an experimental carcinogen in certain test systems.
