Abstract Disclosure: X. Xu: None. X. Hu: None. G. Ma: None. T. Wang: None. J. Wang: None. G. Chen: None. L. Zhao: None. J. Chen: None. Globally, diabetes is among the leading causes of premature morbidity and mortality. Early intervention is crucial to achieve optimal outcomes and minimize the burden of diabetes. Animal models are indispensable tools to investigate etiology and explore novel strategies for diabetes treatment and prevention. Zucker strain and its derivatives, Zucker Fatty (ZF) and Zucker Diabetic Fatty (ZDF) rats, are one of the most used rodent models to study diabetes and diabetes-associated metabolic disorders. Homozygous Zucker rats with leptin receptor gene mutation (Lepr, fa-/-) spontaneously develop obesity, hypercholesterolemia, and hyperlipidemia. The wildtype (fa+/+) and heterozygous (fa+/-) littermates phenotypically are indistinguishable. Furthermore, early stages of diabetes are asymptomatic, and the obese phenotype is not appreciable in homogenous (fa-/-) Zucker rats until week 4 of age. Therefore, a rapid, cost-effective, and reliable genotyping method is essential to differentiate homozygous (fa-/-) rats from either wildtype (fa+/+) or heterozygotes (fa+/-) in early interventional studies. We reported a tetra-primer Amplification-Refractory Mutation System (ARMS)—PCR approach to detect leptin receptor fa mutation using genome DNA collected from ear and tail tissues of Zucker rats. Three different types of amplicon patterns are easily identified by agarose gel electrophoresis. Wildtype (fa+/+) genotype displays a 401 bp and a 201 bp amplicon band; heterozygous (fa+/-) consists of a 401 bp, a 263 bp, and a 201 bp amplicon band on the gel; homozygous (fa-/-) comes up with two bands of 401 bp and 263 bp. The genotypes identified by our tetra-primer ARMS—PCR method are further confirmed by sequence analysis. This method requires neither DNA purification nor restriction enzyme digestion, which is suitable for research exploring gene-environment interaction, as well as implementing appropriate intervention approaches in the research areas of diabetes and metabolic diseases. Presentation: Friday, June 16, 2023