Table 2.

Biomarker Categories, Definitions, and Clinical Applications: Clinical Validation

Biomarker Category	Biomarker Definition	Study Definitions	Clinical Applications
Risk prediction	Cancer is not present, based on current standards; biomarker assesses the probability of cancer developing and being diagnosed over time	Target condition: The diagnosis of lung cancer after a defined period of time	Risk mitigation
		Target population: Individuals without symptoms, signs, or current imaging evidence of the presence of lung cancer	Screening
		Reference standard: Biopsy-confirmed lung cancer after a defined period of time
Cancer detection	Cancer is present but has not been detected. The patient may or may not have symptoms; biomarker identifies the potential presence of cancer	Target condition: Undetected lung cancer	Screening
		Target population: Individuals with or without symptoms or signs of the presence of lung cancer	Symptom evaluation
		Reference standard: Biopsy-confirmed lung cancer
Diagnosis	A nodule, mass, or other imaging finding is known to be present, but its etiology has not been determined; biomarker helps to determine the probability that the finding is malignant	Target condition: Indeterminate lung nodule, mass, or other imaging finding	Evaluation of a lung nodule, mass, or other imaging finding
		Target population: Individuals with imaging showing an indeterminate lung nodule, mass, or other imaging finding
		Reference standard: Biopsy confirmation or surveillance imaging without growth for a period of time, in keeping with current guidelines