There are still many unknowns regarding the potential application of Procalcitonin (PCT) as an adjunct to aid the diagnosis of Prosthetic Joint Infection. A systematic review searching scientific articles was performed with keywords "Procalcitonin", "Total Hip Replacement", and "Total Knee Replacement" (n=123). After review of the abstract and full text for relevance, ten articles were included (n=10). Serum PCT levels for chronic Total Hip Replacement (THR) and Total Knee Replacement (TKR) have a range of mean values from 1.5 ng/ml to 14.2 ng/ml. Specificity ranges from 0.27 to 0.98, while sensitivity is from 0.33 to 0.9. On primary THR/TKR with confirmation of non-infected status, serum PCT peaks between 1-3 days post-operatively, with peak levels varying from 0.12 - 0.79 ng/ml. Based on this review, serum PCT is not a good adjunct in diagnosing Prosthetic Joint Infection (PJI). Synovial fluid PCT fluid may add better clinical support but requires further studies. There were several limitations with this review: the studies are small and heterogeneous, there was a variable definition of PJI, and there was a wide range of mean values, sensitivity and specificity.