RPR is the Rapid Plasma Reactin Cyclic Card Test, which uses cardiolipin as an antigen to check for anticardiolipin antibodies, or reactin, in the serum, a non-specific reaction that can be measured quantitatively and can be used to observe the efficacy of treatment and determine whether there is recurrence and reinfection. RPR can also be positive in lupus erythematosus, leprosy, acute infections, autoimmune diseases, infectious hepatitis, malaria and rheumatoid arthritis, but generally does not exceed 1:8, and attention should be paid to differential diagnosis. The main detection methods include qualitative test and semi-quantitative test. The qualitative test means that after special treatment, the quantitative serum is placed in a well-lit place and the results are observed by the naked eye. The semi-quantitative test is to dilute multiple copies of the serum with saline and observe them in the same way. The titer of the serum with the highest dilution in which the agglutination reaction occurs is used as the basis for the test. It is recommended to fast 12 hours before the RPR test and to avoid excessive alcohol consumption or foods with a high protein content the day before the test to avoid transient changes in blood composition that may affect the test results. If the test result is positive, the test should be actively retested.