title: Optimal cutoff value of serum adenosine deaminase activity for diagnosing acute scrub typhus.
abstract: The objective of this study was to determine the optimal cutoff value of serum adenosine deaminase (ADA) activity for diagnosing scrub typhus in acute febrile patients, especially in the autumn. A total of 715 febrile patients were included; 286 of them were diagnosed with acute scrub typhus. The mean serum ADA activities in patients with and without scrub typhus were 42.8 ± 13.4 IU/L and 17.2 ± 11.5 IU/L, respectively. The optimal cutoff value for serum ADA activity was determined to be 25.0 IU/L with a sensitivity of 92.3%, specificity of 86.6%, and area under the curve of 89.4% using a receiver-operating characteristic curve analysis. The possibility of scrub typhus must be considered when acute febrile patients present with high ADA activity (>25 IU/L), especially in the autumn. Determining the optimal serum ADA activity cutoff value may help clinicians diagnose acute scrub typhus prior to serological confirmation.
authors.affiliation: Department of Internal Medicine, Wonkwang University College of Medicine, Iksan, Korea. john7026@wku.ac.kr
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Lee
authors.forename: Hyo Yeop
authors.initials: HY
authors.lastname: Song
authors.forename: Jeong-Mi
authors.initials: JM
authors.lastname: Lee
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Cho
mesh_terms: D000243:Adenosine Deaminase / Q000097:blood*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012189:Retrospective Studies; D012612:Scrub Typhus / Q000175:diagnosis*; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; C548482:ADA protein, human; D000243:Adenosine Deaminase