OBJECTIVE: To evaluate the diagnostic performance of lipoprotein A (LP(a)) and high-sensitivity C-reactive protein (hs-CRP) combined assay for coronary heart disease (CHD) and their association with the severity of coronary lesions. METHODS: This retrospective study included 106 patients who underwent coronary angiography (CAG) due to thoracic distress at Xi'an International Medical Center Hospital from June 2020 to October 2021. The patients were categorized into two groups: the CHD group (n=67) and the non-CHD group (n=39). Subgroup analysis was performed within the CHD group based on the Gensini score. Serum levels of LP(a) and hs-CRP were compared between the groups and subgroups, and their correlations with the Gensini score were analyzed. The diagnostic performance of LP(a), hs-CRP, and their combined assay for detecting CHD was evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: Serum levels of LP(a) and hs-CRP were significantly higher in the CHD group than those in the non-CHD group (P<
0.001). Within the CHD subgroups, both LP(a) and hs-CRP levels were significantly elevated in the moderate and high Gensini score groups compared to the low Gensini score group (P<
0.001). There was a positive correlation between LP(a) and hs-CRP levels with the Gensini score (r=0.288, P=0.003
r=0.276, P=0.004). The area under the ROC curve (AUC) for the combination of LP(a) and hs-CRP (0.924, 95% CI: 0.865-0.983) was significantly greater than that for LP(a) (0.858, 95% CI: 0.783-0.933) or hs-CRP (0.854, 95% CI: 0.772-0.936) alone (P<
0.05). CONCLUSION: Elevated serum levels of LP(a) and hs-CRP are associated with CHD and correlate with the severity of coronary lesions. The LP(a) and hs-CRP combined assay improves the diagnostic performance for CHD, suggesting potential clinical value.