This study is intended to determine the positive predictive value (PPV) and negative predictive value (NPV) of the multiprotein classifier based on the observed study prevalence of Non-Small Cell Lung Cancer (NSCLC) in the study participants.

Patients must present with previously non-diagnosed lung nodules as found on CT. There is no change to the typical standard of care that any of the investigating physicians and/or centers provide the patients enrolled in this study. The data from this study will not be used to diagnose cancer nor be used to influence treatment decisions for the study participants.

Inclusion Criteria:

• Age ≥ 40 years
• Smoking history: Never, Former, Current
• Subject undergoing diagnostic evaluation for a lung nodule
• Subject undergoing evaluation for a lung nodule by a pulmonologist, and/or by a thoracic surgeon
• Baseline CT scan identifying lung nodule performed within 60 days of subject enrollment
• Nodule(s) identified by CT scan previously not followed
• Subject willing to provide informed consent for the collection of blood specimens

Exclusion Criteria:

• Nodule work-up at the time of enrollment eligibility indicates any prior attempted or completed diagnostic biopsy procedure, such as transthoracic needle aspiration, bronchoscopic biopsy or surgery
• A prior CT scan is available that previously identifies the same lung nodule under consideration for study inclusion on the most current CT scan; AND the prior CT scan was performed more than 60 days before the current CT scan, irrespective of the candidate nodule's radiographic characterization such as size, density or appearance
• Current diagnosis of any cancer
• Prior diagnosis of any cancer within 2 years of lung nodule detection, except for non-melanoma skin cancer
• Administration of blood products, e.g. packed red blood cells, fresh frozen plasma, or platelets, within 30 days of subject enrollment
• History of human immunodeficiency virus (HIV) or Hepatitis C

Subject undergoing evaluation for a lung nodule by a pulmonologist in a pulmonary or chest clinic, and/or by a thoracic surgeon at the time of enrollment