Many horses with bacterial infection of a synovial structure do not survive or regain their full athletic performance. One essential prognostic factor is time from contamination until correct treatment is initiated. Proper treatment requires a microbiological diagnosis and this process takes 2 -3 days. However, with mass spectrophotometry, MALDI TOF, rapid detection of bacteria, “fingerprinting”, is enabled. This project investigates the performance of MALDI TOF rapid microbiological diagnosis under hospital conditions. Synovia from 125 horses with suspected synovial sepsis is analyzed in parallel by conventional phenotyping and by MALDI-TOF after 2, 4, 8 and 24 hours. This will allow 1) evaluation of the performance of MALDI-TOF in synovial sepsis. Further deliverances will be 2) the first description of occurrence and susceptibility pattern of microbes involved in synovial sepsis in Swedish horses and 3) estimates of Swedish survival rates under state-of-the-art hospital conditions.