At some laboratories, such as image #1, there is one overall "test" which contain many "markers".
At other laboratories, such as image #2, there is one overall "report" which contain many "tests".
So some use "test" to describe the overall collection, and others use "test" to describe the individual things inside the collection.
Which way is the optimum use of English?
Would one say "my glucose marker was high"?
Lab #1
Lab #2
Even if you get the results of several tests on one paper, every single test is a separate test. For example, electrolyte panel can contain results for sodium, potassium, chlorine and bicarbonate tests, but you don't need to use the word "test" when describing the results.
When describing the results of actual tests in practice, you can use levels, which can be either high (or elevated) or low (or decreased). You can use levels for minerals (sodium, potassium, iron, magnesium), vitamins, blood cells (leukocytes, neutrophils, monocytes...), glucose, cholesterol, liver enzymes, etc. For example:
Immunological/allergic tests can be positive or negative.
So, there are several possibilities how to mention or not mention the "test" or "result" or "level." You can skip them all if the meaning is clear from the context.
I haven't heard or read that any doctor or health article writer would use "marker" for any test result presented to a patient. Authors usually use the term when discussing new tests in development or comparing new and old type of tests to say, which test result more reliably show the underlying pathology. For example:
