Constitutional indocyanine green excretion defect (CIED) is a rare disorder in which plasma indocyanine green clears markedly slowly (ICG-R15 > 50%), although routine liver function tests are normal. The article describes the first documented case of CIED in a 60-year-old Chinese woman without underlying liver disease. This case expands the geographic and epidemiological spectrum of the disorder. Whole-exome sequencing did not reveal deletions or pathogenic variants in the SLCO1B1 (OATP1B1), SLCO1B3 (OATP1B3), SLC10A1 (NTCP), and ABCC2 (MRP2) genes. The findings rule out conventional mechanisms associated with deficiency of these transporters. Clinical and molecular characterization suggests a new pathogenesis independent of known transporters. The results highlight the need for further research and integration of multiple data when interpreting ICG tests.