The testing will take place at the school on Thursday and it's only being offered to a fraction of the student population.
Contra Costa Health Services will be offering blood tests to only students who may have shared a classroom or was in a club with the student with tuberculosis. About 200 students will be tested.
The county found out about the sick child last month. It then took six days to confirm that the illness was TB. The district says that child is no longer infectious. In fact, the child was back in school on Monday, but the district says the child could have been infectious in January.
TB is an airborne bacterial infection of the lungs and it usually takes at least three months for an infection to develop into a disease. Symptoms of TB disease include coughing lasting more than three weeks, fever, night sweats and unintended weight loss.
The blood tests taking place on Thursday will be the first at a Contra Costa County school since 2009. That's when a student at Antioch High was diagnosed with tuberculosis.