- Email: [email protected]
Direct immunofluorescence assay compared to cell culture for the diagnosis of mucocutaneous herpes simplex virus infections in children
Journal of Clinical Virology 49 (2010) 58–60
Contents lists available at ScienceDirect
Journal of Clinical Virology journal homepage: www.elsevier.com/locate/jcv
Short communication
Direct immunofluorescence assay compared to cell culture for the diagnosis of mucocutaneous herpes simplex virus infections in children A. Chantal Caviness a,∗ , Lindsay L. Oelze a , Ulas E. Saz a , Jewel M. Greer c , Gail J. Demmler-Harrison a,b,c a
Section of Pediatric Emergency Medicine, Baylor College of Medicine, 1102 Bates Avenue, Suite 1850, Houston, TX 77030, United States Section of Pediatric Infectious Disease, Baylor College of Medicine, Houston, TX, United States c Diagnostic Virology Laboratory, Texas Children’s Hospital, Houston, TX, United States b
a r t i c l e
i n f o
Article history: Received 21 April 2010 Received in revised form 11 June 2010 Accepted 15 June 2010 Keywords: Herpes simplex virus Children Sensitivity and specificity
a b s t r a c t Background: Direct immunofluorescence assay (DFA) is commonly used for the rapid identification of herpes simplex virus (HSV) infection in mucocutaneous lesions, yet little is known about its diagnostic accuracy. Objective: To determine the diagnostic yield and accuracy of HSV DFA for the diagnosis of mucocutaneous HSV infection in pediatric patients. Study design: Retrospective cross-sectional study of all patients who underwent HSV DFA testing by the Texas Children’s Hospital Diagnostic Virology between January 1, 1995 and December 31, 2005. HSV DFA sensitivity, specificity, positive likelihood ratio (LRs), and negative LRs were estimated using viral culture as the reference standard. Results: 659 specimens were submitted for HSV DFA with concurrent viral cultures. Viral cultures were positive for HSV type 1 in 158 (24%) and HSV type 2 in 2 (0.3%). There were 433 different patients with a median age of 8.6 years. Types of lesions were as follows: 50% ulcerative, 26% vesicular, 8% erythema or purpura, 5% pustular, and 11% missing. Of the 659 specimens submitted for HSV DFA, 160 (24%) were inconclusive due to inadequate cells. Of the 499 adequate specimens, overall HSV DFA test accuracy was: sensitivity 61%, specificity 99%, LR positive 40, and LR negative 0.39. Conclusions: A quarter of specimens submitted for HSV DFA testing are not adequate for DFA testing. When HSV DFA can be performed, it is specific, but not sensitive, for the identification of mucocutaneous HSV infection in children. © 2010 Elsevier B.V. All rights reserved.
1. Background Herpes simplex viruses (HSV) are common and treatable causes of skin and mucous membrane infections in children and HSV diagnosis is important for patient management. HSV often grows within 1–2 days from skin lesions, while rapid tests, such as direct immunofluorescence assay (DFA), can yield results in as little as 60–90 min. Although HSV DFA testing is widely used, its diagnostic accuracy for the detection of HSV in pediatric patients has not been specifically evaluated. Since the HSV DFA test requires infected cells obtained by swabbing or scraping the base of a lesion, and because children tend to physically resist painful procedures (and move) more than adults, it may be more difficult to
∗ Corresponding author at: Section of Infectious Disease, Baylor College of Medicine, Department of Pediatrics, Texas Children’s Hospital, 1102 Bates Avenue, Suite 1850, Houston, TX 77030, United States. Tel.: +1 832 824 6461; fax: +1 832 825 5424. E-mail address: [email protected] (A.C. Caviness). 1386-6532/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.jcv.2010.06.006
obtain enough cells for DFA testing from pediatric than adult patients. 2. Objectives To determine the diagnostic yield and accuracy of HSV DFA for the diagnosis of mucocutaneous HSV infection in pediatric patients. 3. Study design 3.1. Study population A retrospective cross-sectional study of all specimens submitted for HSV DFA testing and viral culture by the Texas Children’s Hospital Diagnostic Virology Laboratory (TCH DVL) between January 1, 1995 and December 31, 2005 was performed. All TCH inpatients and outpatients of any age for whom samples were submitted for HSV DFA testing and viral culture were included. The study was approved by the Baylor College of Medicine Institutional Review Board.
A.C. Caviness et al. / Journal of Clinical Virology 49 (2010) 58–60
59
3.2. Data collection
4. Results
HSV DFA and viral culture results were obtained from a TCH DVL database while demographic and clinical information were extracted from patient medical records by 2 study investigators (U.E.S. and L.F.).
There were 659 HSV DFAs and viral cultures performed on the same specimens and recorded in the TCH DVL database between January 1, 1995 and December 31, 2005 for 433 different patients. Of the 659 viral cultures, 158 (24.0%) were positive for HSV type 1, 2 (0.3%) for HSV type 2, 9 (1.3%) were positive for non-HSV viruses, and 490 (74.4%) were negative. Medical records were available for 428 (99%) patients: median age 8.6 years (range 2 days to 24 years); 55% male; 39% Hispanic, 35% Caucasian, 15% African-American, and 5% Asian. There were 43 patients on prophylactic antiviral medications with activity against HSV types 1 and 2 at the time of HSV testing: 40% acyclovir, 14% ganciclovir, 12% valacyclovir, 9% foscarnet, 7% famciclovir, 2% cidofovir, and 16% missing. Of those on prophylaxis, 33 had cancer for which 9 were undergoing chemotherapy, 17 were neutropenic, and 38 had undergone bone marrow transplant, 19 within the previous 90 days. Sixty percent of lesions were in the mouth, 21% on the lips, and 19% were on the skin. There were 4 genital lesions. Of the 659 HSV DFAs, 160 (24%) samples were inconclusive due to inadequate cells. The frequency of inconclusive HSV DFA specimens was similar over the study period and across patient and lesion characteristics. Only 15 (9%) inconclusive HSV DFAs were repeated: 9 repeat DFA negative (1 positive HSV type 1 culture) and 6 repeat DFA inconclusive (2 positive HSV type 1 and 4 negative cultures). Excluding the inconclusive specimens, there were 499 specimens from 366 patients. Although there were multiple specimens from 83 patients, only 4 patients underwent multiple tests of the same lesion. In 1 patient who underwent 4 tests over 22 days, the first 2 tests were concordantly positive and the second 2 tests were discordant, with both DFA results being falsely negative. Lesions from the other 3 patients were each tested twice; the first and second tests were all concordant. Because so few lesions underwent multiple testing, each specimen was treated independently for the assessment of HSV DFA accuracy. HSV DFA test sensitivity was low and did not differ significantly by any clinical feature (Table 1). Of the vesicular lesions, the HSV DFA sensitivity was highest in skin lesions (85%). DFA sensitivity was stable over the study years without evidence for improvement over time.
3.3. HSV DFA and cell culture methods HSV viral culture and DFA and typing tests were performed on skin vesicle aspirates or swabs of skin or mucous membrane lesions. Specimens for viral culture were obtained from the patient and transported on ice promptly to the DVL, where they were processed upon receipt in the laboratory. Two cell lines, HFF and A549, were inoculated, incubated at 37 ◦ C on roller drums, and examined daily under light microscopy for the evidence of viral cytopathic effect. Specimens submitted for HSV DFA and typing were obtained from swabs or scrapings of the base of skin or mucous membrane lesions and rolled and rubbed onto glass microscope slides, air dried, fixed in acetone and reacted with a commercially available reagent kit containing HSV type 1 and 2 monoclonal antibodies labeled with fluorescein isothiocyante (MicroTrak HSV1/HSV2, Trinity Biotech, Jamestown, NY 14702) according to the manufacturer’s instructions. Each slide was assessed for adequacy of fixed cells and if an inadequate number of cells were present, the slides were categorized as “Inconclusive” and did not undergo further DFA testing. If the cell number was adequate, cells exhibiting apple-green cytoplasmic staining under fluorescence microscopy were considered positive, while negative cells counterstained red (Evans Blue counterstain). Positive and negative controls were included with each run. 3.4. Analysis Data analysis was performed using IBM SPSS Statistics 18 (SPSS Inc, Chicago, IL). The frequency of specimens inadequate for HSV DFA testing was determined and excluding them and using HSV isolation in viral culture as the reference standard, HSV DFA sensitivity, specificity, likelihood ratio (LR) positive, and LR negative were estimated, along with 95% confidence intervals (CIs) for all subjects and subgroups.
Table 1 Accuracy of HSV DFA compared to HSV culture by patient age, antiviral pre-treatment, chemotherapy, neutropenia, and lesion description in 499 adequate specimens undergoing both HSV DFA and HSV culture. N
HSV positive by DFA N (%)
HSV positive by culture N (%)
% sensitivity (95% CI)
% specificity (95% CI)
Positive likelihood ratio (95% CI)
Negative likelihood ratio (95% CI)
All subjects
499
74 (14.8%)
111 (22.2%)
61.3 (51.5, 70.4)
98.5 (96.7, 99.4)
40 (19, 87)
0.39 (0.36, 0.45)
Age 0–4 years 5–8 years 9+ years
134 91 274
23 (17.2%) 8 (8.8%) 43 (15.7%)
30 (22.4%) 13 (14.3%) 68 (24.8%)
66.7 (47.2, 82.7) 53.9 (25.1, 80.8) 60.3 (47.7, 72.0)
97.1 (91.8, 99.4) 98.7 (93.1, 100.0) 99.0 (96.5, 99.9)
23 (9, 68) 42 (8, 255) 62 (18, 230)
0.34 (0.27, 0.48) 0.47 (0.40, 0.68) 0.40 (0.38, 0.47)
Antiviral pre-treatment No 459 Yes 35
70 (15.3%) 4 (11.4%)
105 (22.9%) 6 (17.1%)
61.0 (50.9, 70.3) 66.7 (22.3, 95.7)
98.3 (96.3, 99.4) 100.0 (88.1, 100.0)
36 (17, 79) Infinity
0.40 (0.36, 0.46) 0.33 (0.33, 0.66)
Chemotherapy No Yes
263 225
44 (16.7%) 30 (13.3%)
60 (22.8%) 49 (21.8%)
65.0 (51.6, 76.9) 59.2 (44.2, 73.0)
97.5 (94.3, 99.2) 99.4 (96.9, 100.0)
26 (12, 62) 104 (20, 600)
0.36 (0.31, 0.45) 0.41 (0.39, 0.49)
Neutropenia No Yes
417 65
62 (14.9%) 12 (18.5%)
91 (21.8%) 17 (26.2%)
62.6 (51.9, 72.6) 64.7 (38.3, 85.8)
98.5 (96.5, 99.5) 97.9 (88.9, 99.9)
41 (18, 96) 31 (6, 182)
0.38 (0.35, 0.44) 0.36 (0.31, 0.55)
Lesion description Ulcerative 255 Vesicular 126 Pustular 20 Other 42
23 (9.0%) 44 (34.9%) 3 (15.0%) 2 (4.8%)
33 (12.9%) 61 (48.4%) 9 (45.0%) 2 (4.8%)
60.6 (42.1, 77.1) 68.9 (55.7, 80.1) 22.2 (2.8, 60.0) 100.0 (15.8, 100.0)
98.7 (96.1, 99.7) 96.9 (89.3, 99.6) 90.9 (58.7, 99.8) 100.0 (91.2, 100.0)
45 (16, 135) 22 (7, 82) 2 (0, 18) Infinity
0.40 (0.34, 0.52) 0.32 (0.29, 0.41) 0.96 (0.70, 1.18) 0.00 (0.00, 0.59)
60
A.C. Caviness et al. / Journal of Clinical Virology 49 (2010) 58–60
Post-evaluation pharmacologic management was documented in the medical records for 529 tested lesions and antiviral treatment was prescribed for 444 (84%) of these. In these 444 lesions, HSV DFA results were inconclusive in 58 (13%), negative in 317 (71%), and positive in 69 (16%). Of the 85 untreated lesions, HSV DFA results were inconclusive in 22 (26%) and negative in 63 (74%).
viral culture in pediatric patients. Clinicians should consider ordering HSV DFA tests only in cases where the results would change treatment decisions. Conflict of interest There are no conflicts of interest to report.
5. Discussion References This study demonstrates that the diagnostic yield and sensitivity of HSV DFA were low relative to viral culture in identifying pediatric HSV infection. Furthermore, patients were typically treated independent of the DFA results for their lesions. Comparing our study findings to other published results, there is evidence that the diagnostic yield and sensitivity of HSV DFA are similar in pediatric and adults patients. The frequency of inadequate specimens (24%) was similar in our pediatric patients compared to that reported in the literature where age was not specified (16–33%).1,2 The sensitivity of HSV DFA testing compared with viral culture was only 1 point lower (61%) in our patient population compared with studies conducted on specimens collected from patients where age was not specified (62–95%).1–9 The study is limited primarily by the use of a secondary data source collected during the course of routine clinical care. Since test performance was at the discretion of the treating physicians, there was opportunity for bias by intention. In addition, the retrospective nature of data collection meant that we were dependent on data recorded in medical records. Finally, since HSV prevalence and HSV DFA LRs may vary, it is important that the clinician understand the disease prevalence and test performance in their center. In conclusion, although HSV DFA has a high specificity for HSV infection, it has a low diagnostic yield and is not as sensitive as HSV
1. Scicchitano LM, Shetterly B, Bourbeau PP. Evaluation of light diagnostics SimulFluor HSV/VZV immunofluorescence assay. Diagn Microbiol Infect Dis 1999;35(November (3)):205–8. 2. Reina J, Saurina J, Fernandez-Baca V, Munar M, Blanco I. Evaluation of a direct immunofluorescence cytospin assay for the detection of herpes simplex virus in clinical samples. Eur J Clin Microbiol Infect Dis 1997;16(November (11)):851–4. 3. Chan EL, Brandt K, Horsman GB. Comparison of Chemicon SimulFluor direct fluorescent antibody staining with cell culture and shell vial direct immunoperoxidase staining for detection of herpes simplex virus and with cytospin direct immunofluorescence staining for detection of varicella-zoster virus. Clin Diagn Lab Immunol 2001;8(September (5)):909–12. 4. Meqdam MM, Todd D, Al-Abosi M. Detection of herpes simplex and varicella zoster viruses in clinical specimens using direct immunofluorescence and cell culture assays. Microbios 2001;105(411):111–8. 5. Schmidt NJ, Gallo D, Devlin V, Woodie JD, Emmons RW. Direct immunofluorescence staining for detection of herpes simplex and varicella-zoster virus antigens in vesicular lesions and certain tissue specimens. J Clin Microbiol 1980;12(November (5)):651–5. 6. Fung JC, Shanley J, Tilton RC. Comparison of the detection of herpes simplex virus in direct clinical specimens with herpes simplex virus-specific DNA probes and monoclonal antibodies. J Clin Microbiol 1985;22(November (5)):748–53. 7. Volpi A, Lakeman AD, Pereira L, Stagno S. Monoclonal antibodies for rapid diagnosis and typing of genital herpes infections during pregnancy. Am J Obstet Gynecol 1983;146(August (7)):813–5. 8. Landry ML, Ferguson D, Wlochowski J. Detection of herpes simplex virus in clinical specimens by cytospin-enhanced direct immunofluorescence. J Clin Microbiol 1997;35(January (1)):302–4. 9. Goldstein LC, Corey L, McDougall JK, Tolentino E, Nowinski RC. Monoclonal antibodies to herpes simplex viruses: use in antigenic typing and rapid diagnosis. J Infect Dis 1983;147(May (5)):829–37.
Contents lists available at ScienceDirect
Journal of Clinical Virology journal homepage: www.elsevier.com/locate/jcv
Short communication
Direct immunofluorescence assay compared to cell culture for the diagnosis of mucocutaneous herpes simplex virus infections in children A. Chantal Caviness a,∗ , Lindsay L. Oelze a , Ulas E. Saz a , Jewel M. Greer c , Gail J. Demmler-Harrison a,b,c a
Section of Pediatric Emergency Medicine, Baylor College of Medicine, 1102 Bates Avenue, Suite 1850, Houston, TX 77030, United States Section of Pediatric Infectious Disease, Baylor College of Medicine, Houston, TX, United States c Diagnostic Virology Laboratory, Texas Children’s Hospital, Houston, TX, United States b
a r t i c l e
i n f o
Article history: Received 21 April 2010 Received in revised form 11 June 2010 Accepted 15 June 2010 Keywords: Herpes simplex virus Children Sensitivity and specificity
a b s t r a c t Background: Direct immunofluorescence assay (DFA) is commonly used for the rapid identification of herpes simplex virus (HSV) infection in mucocutaneous lesions, yet little is known about its diagnostic accuracy. Objective: To determine the diagnostic yield and accuracy of HSV DFA for the diagnosis of mucocutaneous HSV infection in pediatric patients. Study design: Retrospective cross-sectional study of all patients who underwent HSV DFA testing by the Texas Children’s Hospital Diagnostic Virology between January 1, 1995 and December 31, 2005. HSV DFA sensitivity, specificity, positive likelihood ratio (LRs), and negative LRs were estimated using viral culture as the reference standard. Results: 659 specimens were submitted for HSV DFA with concurrent viral cultures. Viral cultures were positive for HSV type 1 in 158 (24%) and HSV type 2 in 2 (0.3%). There were 433 different patients with a median age of 8.6 years. Types of lesions were as follows: 50% ulcerative, 26% vesicular, 8% erythema or purpura, 5% pustular, and 11% missing. Of the 659 specimens submitted for HSV DFA, 160 (24%) were inconclusive due to inadequate cells. Of the 499 adequate specimens, overall HSV DFA test accuracy was: sensitivity 61%, specificity 99%, LR positive 40, and LR negative 0.39. Conclusions: A quarter of specimens submitted for HSV DFA testing are not adequate for DFA testing. When HSV DFA can be performed, it is specific, but not sensitive, for the identification of mucocutaneous HSV infection in children. © 2010 Elsevier B.V. All rights reserved.
1. Background Herpes simplex viruses (HSV) are common and treatable causes of skin and mucous membrane infections in children and HSV diagnosis is important for patient management. HSV often grows within 1–2 days from skin lesions, while rapid tests, such as direct immunofluorescence assay (DFA), can yield results in as little as 60–90 min. Although HSV DFA testing is widely used, its diagnostic accuracy for the detection of HSV in pediatric patients has not been specifically evaluated. Since the HSV DFA test requires infected cells obtained by swabbing or scraping the base of a lesion, and because children tend to physically resist painful procedures (and move) more than adults, it may be more difficult to
∗ Corresponding author at: Section of Infectious Disease, Baylor College of Medicine, Department of Pediatrics, Texas Children’s Hospital, 1102 Bates Avenue, Suite 1850, Houston, TX 77030, United States. Tel.: +1 832 824 6461; fax: +1 832 825 5424. E-mail address: [email protected] (A.C. Caviness). 1386-6532/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.jcv.2010.06.006
obtain enough cells for DFA testing from pediatric than adult patients. 2. Objectives To determine the diagnostic yield and accuracy of HSV DFA for the diagnosis of mucocutaneous HSV infection in pediatric patients. 3. Study design 3.1. Study population A retrospective cross-sectional study of all specimens submitted for HSV DFA testing and viral culture by the Texas Children’s Hospital Diagnostic Virology Laboratory (TCH DVL) between January 1, 1995 and December 31, 2005 was performed. All TCH inpatients and outpatients of any age for whom samples were submitted for HSV DFA testing and viral culture were included. The study was approved by the Baylor College of Medicine Institutional Review Board.
A.C. Caviness et al. / Journal of Clinical Virology 49 (2010) 58–60
59
3.2. Data collection
4. Results
HSV DFA and viral culture results were obtained from a TCH DVL database while demographic and clinical information were extracted from patient medical records by 2 study investigators (U.E.S. and L.F.).
There were 659 HSV DFAs and viral cultures performed on the same specimens and recorded in the TCH DVL database between January 1, 1995 and December 31, 2005 for 433 different patients. Of the 659 viral cultures, 158 (24.0%) were positive for HSV type 1, 2 (0.3%) for HSV type 2, 9 (1.3%) were positive for non-HSV viruses, and 490 (74.4%) were negative. Medical records were available for 428 (99%) patients: median age 8.6 years (range 2 days to 24 years); 55% male; 39% Hispanic, 35% Caucasian, 15% African-American, and 5% Asian. There were 43 patients on prophylactic antiviral medications with activity against HSV types 1 and 2 at the time of HSV testing: 40% acyclovir, 14% ganciclovir, 12% valacyclovir, 9% foscarnet, 7% famciclovir, 2% cidofovir, and 16% missing. Of those on prophylaxis, 33 had cancer for which 9 were undergoing chemotherapy, 17 were neutropenic, and 38 had undergone bone marrow transplant, 19 within the previous 90 days. Sixty percent of lesions were in the mouth, 21% on the lips, and 19% were on the skin. There were 4 genital lesions. Of the 659 HSV DFAs, 160 (24%) samples were inconclusive due to inadequate cells. The frequency of inconclusive HSV DFA specimens was similar over the study period and across patient and lesion characteristics. Only 15 (9%) inconclusive HSV DFAs were repeated: 9 repeat DFA negative (1 positive HSV type 1 culture) and 6 repeat DFA inconclusive (2 positive HSV type 1 and 4 negative cultures). Excluding the inconclusive specimens, there were 499 specimens from 366 patients. Although there were multiple specimens from 83 patients, only 4 patients underwent multiple tests of the same lesion. In 1 patient who underwent 4 tests over 22 days, the first 2 tests were concordantly positive and the second 2 tests were discordant, with both DFA results being falsely negative. Lesions from the other 3 patients were each tested twice; the first and second tests were all concordant. Because so few lesions underwent multiple testing, each specimen was treated independently for the assessment of HSV DFA accuracy. HSV DFA test sensitivity was low and did not differ significantly by any clinical feature (Table 1). Of the vesicular lesions, the HSV DFA sensitivity was highest in skin lesions (85%). DFA sensitivity was stable over the study years without evidence for improvement over time.
3.3. HSV DFA and cell culture methods HSV viral culture and DFA and typing tests were performed on skin vesicle aspirates or swabs of skin or mucous membrane lesions. Specimens for viral culture were obtained from the patient and transported on ice promptly to the DVL, where they were processed upon receipt in the laboratory. Two cell lines, HFF and A549, were inoculated, incubated at 37 ◦ C on roller drums, and examined daily under light microscopy for the evidence of viral cytopathic effect. Specimens submitted for HSV DFA and typing were obtained from swabs or scrapings of the base of skin or mucous membrane lesions and rolled and rubbed onto glass microscope slides, air dried, fixed in acetone and reacted with a commercially available reagent kit containing HSV type 1 and 2 monoclonal antibodies labeled with fluorescein isothiocyante (MicroTrak HSV1/HSV2, Trinity Biotech, Jamestown, NY 14702) according to the manufacturer’s instructions. Each slide was assessed for adequacy of fixed cells and if an inadequate number of cells were present, the slides were categorized as “Inconclusive” and did not undergo further DFA testing. If the cell number was adequate, cells exhibiting apple-green cytoplasmic staining under fluorescence microscopy were considered positive, while negative cells counterstained red (Evans Blue counterstain). Positive and negative controls were included with each run. 3.4. Analysis Data analysis was performed using IBM SPSS Statistics 18 (SPSS Inc, Chicago, IL). The frequency of specimens inadequate for HSV DFA testing was determined and excluding them and using HSV isolation in viral culture as the reference standard, HSV DFA sensitivity, specificity, likelihood ratio (LR) positive, and LR negative were estimated, along with 95% confidence intervals (CIs) for all subjects and subgroups.
Table 1 Accuracy of HSV DFA compared to HSV culture by patient age, antiviral pre-treatment, chemotherapy, neutropenia, and lesion description in 499 adequate specimens undergoing both HSV DFA and HSV culture. N
HSV positive by DFA N (%)
HSV positive by culture N (%)
% sensitivity (95% CI)
% specificity (95% CI)
Positive likelihood ratio (95% CI)
Negative likelihood ratio (95% CI)
All subjects
499
74 (14.8%)
111 (22.2%)
61.3 (51.5, 70.4)
98.5 (96.7, 99.4)
40 (19, 87)
0.39 (0.36, 0.45)
Age 0–4 years 5–8 years 9+ years
134 91 274
23 (17.2%) 8 (8.8%) 43 (15.7%)
30 (22.4%) 13 (14.3%) 68 (24.8%)
66.7 (47.2, 82.7) 53.9 (25.1, 80.8) 60.3 (47.7, 72.0)
97.1 (91.8, 99.4) 98.7 (93.1, 100.0) 99.0 (96.5, 99.9)
23 (9, 68) 42 (8, 255) 62 (18, 230)
0.34 (0.27, 0.48) 0.47 (0.40, 0.68) 0.40 (0.38, 0.47)
Antiviral pre-treatment No 459 Yes 35
70 (15.3%) 4 (11.4%)
105 (22.9%) 6 (17.1%)
61.0 (50.9, 70.3) 66.7 (22.3, 95.7)
98.3 (96.3, 99.4) 100.0 (88.1, 100.0)
36 (17, 79) Infinity
0.40 (0.36, 0.46) 0.33 (0.33, 0.66)
Chemotherapy No Yes
263 225
44 (16.7%) 30 (13.3%)
60 (22.8%) 49 (21.8%)
65.0 (51.6, 76.9) 59.2 (44.2, 73.0)
97.5 (94.3, 99.2) 99.4 (96.9, 100.0)
26 (12, 62) 104 (20, 600)
0.36 (0.31, 0.45) 0.41 (0.39, 0.49)
Neutropenia No Yes
417 65
62 (14.9%) 12 (18.5%)
91 (21.8%) 17 (26.2%)
62.6 (51.9, 72.6) 64.7 (38.3, 85.8)
98.5 (96.5, 99.5) 97.9 (88.9, 99.9)
41 (18, 96) 31 (6, 182)
0.38 (0.35, 0.44) 0.36 (0.31, 0.55)
Lesion description Ulcerative 255 Vesicular 126 Pustular 20 Other 42
23 (9.0%) 44 (34.9%) 3 (15.0%) 2 (4.8%)
33 (12.9%) 61 (48.4%) 9 (45.0%) 2 (4.8%)
60.6 (42.1, 77.1) 68.9 (55.7, 80.1) 22.2 (2.8, 60.0) 100.0 (15.8, 100.0)
98.7 (96.1, 99.7) 96.9 (89.3, 99.6) 90.9 (58.7, 99.8) 100.0 (91.2, 100.0)
45 (16, 135) 22 (7, 82) 2 (0, 18) Infinity
0.40 (0.34, 0.52) 0.32 (0.29, 0.41) 0.96 (0.70, 1.18) 0.00 (0.00, 0.59)
60
A.C. Caviness et al. / Journal of Clinical Virology 49 (2010) 58–60
Post-evaluation pharmacologic management was documented in the medical records for 529 tested lesions and antiviral treatment was prescribed for 444 (84%) of these. In these 444 lesions, HSV DFA results were inconclusive in 58 (13%), negative in 317 (71%), and positive in 69 (16%). Of the 85 untreated lesions, HSV DFA results were inconclusive in 22 (26%) and negative in 63 (74%).
viral culture in pediatric patients. Clinicians should consider ordering HSV DFA tests only in cases where the results would change treatment decisions. Conflict of interest There are no conflicts of interest to report.
5. Discussion References This study demonstrates that the diagnostic yield and sensitivity of HSV DFA were low relative to viral culture in identifying pediatric HSV infection. Furthermore, patients were typically treated independent of the DFA results for their lesions. Comparing our study findings to other published results, there is evidence that the diagnostic yield and sensitivity of HSV DFA are similar in pediatric and adults patients. The frequency of inadequate specimens (24%) was similar in our pediatric patients compared to that reported in the literature where age was not specified (16–33%).1,2 The sensitivity of HSV DFA testing compared with viral culture was only 1 point lower (61%) in our patient population compared with studies conducted on specimens collected from patients where age was not specified (62–95%).1–9 The study is limited primarily by the use of a secondary data source collected during the course of routine clinical care. Since test performance was at the discretion of the treating physicians, there was opportunity for bias by intention. In addition, the retrospective nature of data collection meant that we were dependent on data recorded in medical records. Finally, since HSV prevalence and HSV DFA LRs may vary, it is important that the clinician understand the disease prevalence and test performance in their center. In conclusion, although HSV DFA has a high specificity for HSV infection, it has a low diagnostic yield and is not as sensitive as HSV
1. Scicchitano LM, Shetterly B, Bourbeau PP. Evaluation of light diagnostics SimulFluor HSV/VZV immunofluorescence assay. Diagn Microbiol Infect Dis 1999;35(November (3)):205–8. 2. Reina J, Saurina J, Fernandez-Baca V, Munar M, Blanco I. Evaluation of a direct immunofluorescence cytospin assay for the detection of herpes simplex virus in clinical samples. Eur J Clin Microbiol Infect Dis 1997;16(November (11)):851–4. 3. Chan EL, Brandt K, Horsman GB. Comparison of Chemicon SimulFluor direct fluorescent antibody staining with cell culture and shell vial direct immunoperoxidase staining for detection of herpes simplex virus and with cytospin direct immunofluorescence staining for detection of varicella-zoster virus. Clin Diagn Lab Immunol 2001;8(September (5)):909–12. 4. Meqdam MM, Todd D, Al-Abosi M. Detection of herpes simplex and varicella zoster viruses in clinical specimens using direct immunofluorescence and cell culture assays. Microbios 2001;105(411):111–8. 5. Schmidt NJ, Gallo D, Devlin V, Woodie JD, Emmons RW. Direct immunofluorescence staining for detection of herpes simplex and varicella-zoster virus antigens in vesicular lesions and certain tissue specimens. J Clin Microbiol 1980;12(November (5)):651–5. 6. Fung JC, Shanley J, Tilton RC. Comparison of the detection of herpes simplex virus in direct clinical specimens with herpes simplex virus-specific DNA probes and monoclonal antibodies. J Clin Microbiol 1985;22(November (5)):748–53. 7. Volpi A, Lakeman AD, Pereira L, Stagno S. Monoclonal antibodies for rapid diagnosis and typing of genital herpes infections during pregnancy. Am J Obstet Gynecol 1983;146(August (7)):813–5. 8. Landry ML, Ferguson D, Wlochowski J. Detection of herpes simplex virus in clinical specimens by cytospin-enhanced direct immunofluorescence. J Clin Microbiol 1997;35(January (1)):302–4. 9. Goldstein LC, Corey L, McDougall JK, Tolentino E, Nowinski RC. Monoclonal antibodies to herpes simplex viruses: use in antigenic typing and rapid diagnosis. J Infect Dis 1983;147(May (5)):829–37.