The war against cancer has yielded important advances in the early diagnosis and treatment of certain cancer types, but the poor detection rate and 5-year survival rate for lung cancer has changed little over the past 40 years. Early detection through emerging lung cancer screening programs promise the most reliable means of improving mortality. Sputum cytology has been tried without success because sputum contains few malignant cells that are difficult for cytologists to detect. However, research has shown that sputum contains diagnostic malignant cells and could serve as a means of lung cancer detection if those cells could be detected and correctly characterized. Recently, the National Lung Screening Trial reported that screening using 3 consecutive low-dose x-ray computed tomography scans provides a 20% reduction in lung cancer mortality compared with chest x-ray. However, this reduction in mortality comes with an unacceptable false-positive rate that increases patient risks and the overall cost of lung cancer screening. The LuCED test for detection of early lung cancer is reviewed in the current article. LuCED is based on patient sputum that is enriched for bronchial epithelial cells. The enriched sample is then processed on the Cell-CT, which images cells in 3 dimensions with submicron resolution. Algorithms are applied to the 3-dimensional cell images to extract morphometric features that drive a classifier to identify cells that have abnormal characteristics. The final status of these candidate abnormal cells is established by the pathologist's manual review. LuCED promotes accurate cell classification that could enable the cost-effective detection of lung cancer.