Evaluation of the shell vial technique for detection of ocular adenovirus. Community Ophthalmologists of Pittsburgh, Pennsylvania.
OBJECTIVE
The shell vial technique is a cell culture method that uses centrifugation and immunofluorescence to decrease the time required for a positive test. The authors evaluated the shell vial technique as a diagnostic test to detect adenovirus in conjunctival specimens of patients with adenoviral conjunctivitis.


METHODS
Retrospective and prospective case series.


METHODS
Forty-six patients with adenoviral culture-positive ocular infection.


METHODS
The minimum time of incubation (days) that was required for testing clinical isolates with the shell vial was determined with adenovirus serotypes 5 and 8. In a masked retrospective study, 25 true-positive (frozen clinical samples) and 25 true-negative specimens were tested for the presence of adenovirus using the shell vial technique. The 25 true-negative samples included herpes simplex virus, Chlamydia trachomatis, Haemophilus influenzae, Streptococcus pneumoniae, and Staphylococcus aureus. In a prospective study, 21 patients who later tested positive in cell culture for adenovirus were concurrently tested with shell vial.


METHODS
The time of incubation was determined in days, and the sensitivity, specificity, positive and negative predictive values, and the efficacy of the shell vial test were determined.


RESULTS
The minimal time of incubation for testing ocular samples by shell vial was 3 days. In the retrospective study, the sensitivity, specificity, positive predictive value, negative predictive value, and efficacy were 92%, 100%, 100%, 93%, and 96%, respectively. Comparably (P = 0.99), in the prospective study the sensitivity, specificity, positive predictive value, negative predictive value, and efficacy were 95%, 100%, 100%, 96%, and 97%, respectively. The shell vial (93%, 43 of 46) was equivalent (P = 0.42) to cell culture (100%, 46 of 46) for detecting adenovirus, but a positive result was obtained in significantly less time (3 days versus 9.41 +/- 6.23 days) (P = 0.00001).


CONCLUSIONS
The shell vial technique was found to be a definitive method for identifying adenovirus from ocular specimens. A clear benefit for the ophthalmologist is that the test can provide a faster positive result (3 days) compared with conventional cell culture, which can take 1 to 3 weeks for adenovirus isolation.
Department of Ophthalmology, University of Pittsburgh and Medical Center, Pennsylvania, USA. Rege@vision.eei.upmc.edu
R P
RP
Kowalski
L M
LM
Karenchak
E G
EG
Romanowski
Y J
YJ
Gordon
D000258:Adenovirus Infections, Human / Q000175:diagnosis* / Q000821:virology; D000260:Adenoviruses, Human / Q000302:isolation & purification*; D003228:Conjunctiva / Q000821:virology*; D003236:Conjunctivitis, Viral / Q000175:diagnosis* / Q000821:virology; D003941:Diagnostic Techniques, Ophthalmological; D004847:Epithelial Cells / Q000473:pathology / Q000821:virology; D015828:Eye Infections, Viral / Q000175:diagnosis* / Q000821:virology; D005189:False Positive Reactions; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008856:Microscopy, Fluorescence; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014776:Virus Cultivation