title: Serum Procalcitonin is a sensitive and specific marker in the diagnosis of septic arthritis and acute osteomyelitis.
abstract: BACKGROUND
  Early diagnosis of Acute Osteomyelitis (OM) and Septic Arthritis (SA) is of vital importance to avoid devastating complications. There is no single laboratory marker which is sensitive and specific in diagnosing these infections accurately. Total Count, ESR and CRP are not specific as they can also be elevated in non pyogenic causes of inflammation. Pus Culture and sensitivity is not a true gold standard due to its varied positivity rates (40 - 70%). Serum Procalcitonin (PCT), at 0.5 ng/ml is found to be an accurate marker for pyogenic infections. The objectives of this study were to show that PCT is an accurate marker in differentiating Acute Osteomyelitis and Septic Arthritis from viral and non infective inflammatory bone and joint conditions.
  
  
  METHODS
  Patients of all age groups (n = 82) with suspected Acute Osteomyelitis and Septic Arthritis were prospectively included in this study. All patients were subjected to TC, CRP, PCT, IgM Dengue, IgM Chikungunya, pus and blood culture and sensitivity. At the end of the study, patients were classified into 3 groups: Group 1 = Confirmed Pyogenic (n = 27); Group 2 = Presumed Pyogenic (n = 21); Group 3 = Non - infective inflammatory (n = 34).
  
  
  RESULTS
  Group 1 has higher mean PCT levels than Group 2 and 3 (p < 0.05). PCT, at 0.4 ng/ml, was 85.2% sensitive and 87.3% specific in diagnosing Septic Arthritis and Acute Osteomyelitis. In comparison, PCT at conventional cut - off of 0.5 ng/ml is 66.7% sensitive and 91% specific.
  
  
  CONCLUSIONS
  Serum Procalcitonin, at a cut - off of 0.4 ng/ml, is a sensitive and specific marker in the diagnosis of Septic Arthritis and Acute Osteomyelitis.
authors.affiliation: Department of Orthopedics, JIPMER, Puducherry, India. drkarthik_ortho_jipmer@yahoo.in
authors.forename: Karthikeyan
authors.initials: K
authors.lastname: Maharajan
authors.forename: Dilip Kumar
authors.initials: DK
authors.lastname: Patro
authors.forename: Jagdish
authors.initials: J
authors.lastname: Menon
authors.forename: Ananthanarayanan Palghat
authors.initials: AP
authors.lastname: Hariharan
authors.forename: Sabhash Chandra
authors.initials: SC
authors.lastname: Parija
authors.forename: Murali
authors.initials: M
authors.lastname: Poduval
authors.forename: Sreenivas
authors.initials: S
authors.lastname: Thimmaiah
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001170:Arthritis, Infectious / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000378:metabolism; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D010019:Osteomyelitis / Q000175:diagnosis*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood*; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide