title: Laboratory diagnosis of SARS.
abstract: The virologic test results of 415 patients with severe acute respiratory syndrome (SARS) were examined. The peak detection rate for SARS-associated coronavirus occurred at week 2 after illness onset for respiratory specimens, at weeks 2 to 3 for stool or rectal swab specimens, and at week 4 for urine specimens. The latest stool sample that was positive by reverse transcription-polymerase chain reaction (RT-PCR) was collected on day 75 while the patient was receiving intensive care. Tracheal aspirate and stool samples had a higher diagnostic yield (RT-PCR average positive rate for first 2 weeks: 66.7% and 56.5%, respectively). Pooled throat and nasal swabs, rectal swab, nasal swab, throat swab, and nasopharyngeal aspirate specimens provided a moderate yield (29.7%-40.0%), whereas throat washing and urine specimens showed a lower yield (17.3% and 4.5%). The collection procedures for stool and pooled nasal and throat swab specimens were the least likely to transmit infection, and the combination gave the highest yield for coronavirus detection by RT-PCR. Positive virologic test results in patient groups were associated with mechanical ventilation or death (p < 0.001), suggesting a correlation between viral load and disease severity.
authors.affiliation: Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong Special Administrative Region, China. paulkschan@cuhk.edu.hk
authors.forename: Paul K S
authors.initials: PK
authors.lastname: Chan
authors.forename: Wing-Kin
authors.initials: WK
authors.lastname: To
authors.forename: King-Cheung
authors.initials: KC
authors.lastname: Ng
authors.forename: Rebecca K Y
authors.initials: RK
authors.lastname: Lam
authors.forename: Tak-Keung
authors.initials: TK
authors.lastname: Ng
authors.forename: Rickjason C W
authors.initials: RC
authors.lastname: Chan
authors.forename: Alan
authors.initials: A
authors.lastname: Wu
authors.forename: Wai-Cho
authors.initials: WC
authors.lastname: Yu
authors.forename: Nelson
authors.initials: N
authors.lastname: Lee
authors.forename: David S C
authors.initials: DS
authors.lastname: Hui
authors.forename: Sik-To
authors.initials: ST
authors.lastname: Lai
authors.forename: Ellis K L
authors.initials: EK
authors.lastname: Hon
authors.forename: Chi-Kong
authors.initials: CK
authors.lastname: Li
authors.forename: Joseph J Y
authors.initials: JJ
authors.lastname: Sung
authors.forename: John S
authors.initials: JS
authors.lastname: Tam
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D019411:Clinical Laboratory Techniques; D021821:Communicable Diseases, Emerging / Q000175:diagnosis* / Q000453:epidemiology / Q000821:virology; D004196:Disease Outbreaks; D005243:Feces / Q000821:virology; D005260:Female; D006723:Hong Kong; D006801:Humans; D008297:Male; D008875:Middle Aged; D012367:RNA, Viral / Q000032:analysis / Q000302:isolation & purification; D012137:Respiratory System / Q000821:virology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D045473:Severe acute respiratory syndrome-related coronavirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D045169:Severe Acute Respiratory Syndrome / Q000175:diagnosis* / Q000453:epidemiology / Q000821:virology; D013997:Time Factors; D014556:Urine / Q000821:virology; D017201:Virus Shedding
chemical_list: D012367:RNA, Viral