Cer(d18:1/24:1) and Cer(d18:1/24:0) are specific ceramide species, a class of sphingolipids found in cell membranes and circulating lipoproteins. Chemically they share the sphingoid base (d18:1) but differ in the fatty acid at carbon 24: one has a double bond (24:1) and the other is saturated (24:0). The ratio compares the relative abundance of these two molecular species. Historically, ceramides emerged from basic lipid biology and later from clinical studies linking certain ceramide species and ratios to cardiometabolic patterns. Biologically, ceramides influence membrane structure, cell stress responses, programmed cell turnover, and signaling pathways that touch inflammation and lipid trafficking. Differences in specific ceramide levels can reflect shifts in fatty acid metabolism, liver lipid processing, and lipoprotein composition.

Higher values of this ratio generally indicate a relative increase in the monounsaturated 24:1 species versus the saturated 24:0 species. Studies associate higher ceramide ratios with metabolic stress patterns—such as altered fatty acid desaturation, insulin resistance markers, and inflammatory signaling—but these are associations rather than diagnostic statements. Low values indicate the opposite balance and may reflect different fatty acid handling or lower circulating ceramide activity. Interpretation depends on the whole Cardio Zoomer profile: lipoprotein particle counts, ApoB, triglycerides, glucose/insulin markers, and inflammation biomarkers all help clarify whether a ceramide ratio shift signals a meaningful metabolic pattern or isolated variation.

Cardio Zoomer includes this ceramide ratio to assess lipid quality and metabolic pathway activity not captured by cholesterol levels alone. It helps identify patterns of fatty acid metabolism, lipoprotein behavior, and inflammation that can shape cardiovascular risk signals. Combined with other markers, the ratio refines individualized assessments and supports targeted clinical interpretation.