The phrase "a primary marker" is correct and usable in written English.
It can be used to refer to a significant or main indicator of something in various contexts, such as research, analysis, or description.
Example: "In the study of human behavior, a primary marker of emotional distress is often changes in sleep patterns."
Alternatives: "a key indicator" or "a main sign".
This article presents a research method for assessing stress and mental health in ongoing population-based social surveys that combines self-reports of naturally occurring daily stressors with a primary marker of stress physiology, salivary cortisol.
With Pfg377 as a primary marker recognising only female gametocytes, and α-tubulin II as a secondary marker for accurately enumerating the denominator of viable gametocytes, robust sex ratios could be derived for preparations of gametocytes at stage IV or later.
Similarly, while C8 is a primary marker of MCAD, it's also a primary marker for GA-II, M/SCHAD and MCKAT.
PD-1 has been considered as a primary marker for exhausted T cells.
As a primary marker of biological activity STAT3 phosphorylation was measured in 29 patients from the Australian trial.
In the Yali tribe, number of pigs is a primary marker of wealth (and hence good nutrition).
The court typically takes up only those questions that have produced contradictory rulings in the lower courts; a "conflict in the circuits" is the primary marker of a case the justices deem worthy of their attention.
The a priori primary markers of interest in this study (anti-HIV and anti-HSV activity) were evaluated with no adjustment of the p-value for multiple testing.
Unlike target selection for therapeutic development, a radiotracer target needs only to demonstrate altered expression, occupancy levels, or function in the disease state, making it a secondary, as opposed to primary, marker for the disease.
A decreased peak VO2 along with a reduced AT has been the primary marker of reduced exercise capacity in patients with cardiovascular limitations to exercise [21].
Low avidity IgG was used to supplement findings by these three markers in some of the cases, but it was not used as a primary diagnostic marker in the present study, because its specificity has not yet been established.
