PSA

PSA, PsA, Psa, or psa may refer to:

== Biology and medicine == Posterior spinal artery Primary systemic amyloidosis, a disease caused by the accumulation of abnormal proteins Prostate-specific antigen, an enzyme used as a blood tracer for prostate cancer Psoriatic arthritis, an inflammatory disease Pseudomonas aeruginosa, a species of bacterium Pseudomonas syringae pv. actinidiae, a pathovar of a bacterium that attacks kiwifruit