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A 1-year evaluation of Syva MicroTrak Chlamydia enzyme immunoassay with selective confirmation by direct fluorescent-antibody assay in a high-volume laboratory.

https://arctichealth.org/en/permalink/ahliterature217461
Source
J Clin Microbiol. 1994 Sep;32(9):2208-11
Publication Type
Article
Date
Sep-1994
Author
E L Chan
K. Brandt
G B Horsman
Author Affiliation
Laboratory and Disease Control Services, Saskatchewan Health, Regina, Canada.
Source
J Clin Microbiol. 1994 Sep;32(9):2208-11
Date
Sep-1994
Language
English
Publication Type
Article
Keywords
Algorithms
Chlamydia Infections - diagnosis - epidemiology - microbiology
Chlamydia trachomatis - immunology - isolation & purification
Cost Control
Densitometry
Diagnostic Tests, Routine - economics
Evaluation Studies as Topic
Female
Fluorescent Antibody Technique - economics
Humans
Immunoenzyme Techniques - economics
Male
Predictive value of tests
Prevalence
Reagent kits, diagnostic
Saskatchewan - epidemiology
Seasons
Sensitivity and specificity
Urethritis - diagnosis - epidemiology - microbiology
Uterine Cervicitis - diagnosis - epidemiology - microbiology
Abstract
TThe Syva MicroTrak Chlamydia enzyme immunoassay (EIA; Syva Company, San Jose, Calif.) with cytospin and direct fluorescent-antibody assay (DFA) confirmation was evaluated on 43,630 urogenital specimens over a 1-year period in the Provincial Laboratory in Regina, Saskatchewan, Canada. This was a two-phase study intended to define a testing algorithm for Chlamydia trachomatis that would be both highly accurate and cost-effective in our high-volume (> 3,000 tests per month) laboratory. The prevalence of C. trachomatis infection in our population is moderate (8 to 9%). In phase 1, we tested 6,022 male and female urogenital specimens by EIA. All specimens with optical densities above the cutoff value and those within 30% below the cutoff value were retested by DFA. This was 648 specimens (10.8% of the total). A total of 100% (211 of 211) of the specimens with optical densities equal to or greater than 1.00 absorbance unit (AU) above the cutoff value, 98.2% (175 of 178) of the specimens with optical densities of between 0.500 and 0.999 AU above the cutoff value, and 83% (167 of 201) of the specimens with optical densities within 0.499 AU above the cutoff value were confirmed to be positive. A total of 12% (7 of 58) of the specimens with optical densities within 30% below the cutoff value were positive by DFA. In phase 2, we tested 37,608 specimens (32,495 from females; 5,113 from males) by EIA. Only those specimens with optical densities of between 0.499 AU above and 30% below the cutoff value required confirmation on the basis of data from phase 1 of the study. This was 4.5% of all specimens tested. This decrease in the proportion of specimens requiring confirmation provides a significant cost savings to the laboratory. The testing algorithm gives us a 1-day turnaround time to the final confirmed test results. The MicroTrak EIA performed very well in both phases of the study, with a sensitivity, specificity, positive predictive value, and negative predictive value of 96.1, 99.1, 90.3, and 99.7%, respectively, in phase 2. We suggest that for laboratories that use EIA for Chlamydia testing, a study such as this one will identify an appropriate optical density range for confirmatory testing for samples from that particular population.
Notes
Cites: Epidemiol Rev. 1983;5:96-1236357824
Cites: J Clin Microbiol. 1993 Jun;31(6):1646-78315010
Cites: Diagn Microbiol Infect Dis. 1992 Nov-Dec;15(8):663-81478048
Cites: J Clin Microbiol. 1990 Nov;28(11):2473-62254422
PubMed ID
7814548 View in PubMed
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An economic evaluation of screening for Chlamydia trachomatis in adolescent males.

https://arctichealth.org/en/permalink/ahliterature75124
Source
JAMA. 1993 Nov 3;270(17):2057-64
Publication Type
Article
Date
Nov-3-1993
Author
M. Genç
L. Ruusuvaara
P A Mårdh
Author Affiliation
Uppsala University Centre for STD Research, Sweden.
Source
JAMA. 1993 Nov 3;270(17):2057-64
Date
Nov-3-1993
Language
English
Publication Type
Article
Keywords
Adolescent
Azithromycin - therapeutic use
Carboxylic Ester Hydrolases - urine
Chlamydia Infections - diagnosis - drug therapy - prevention & control - urine
Chlamydia trachomatis
Cost-Benefit Analysis
Decision Support Techniques
Doxycycline - therapeutic use
Humans
Immunoenzyme Techniques - economics
Male
Mass Screening - economics - methods
Research Support, Non-U.S. Gov't
Sweden
Abstract
OBJECTIVE--To assess the cost-effectiveness of identifying asymptomatic carriers of Chlamydia trachomatis among adolescent males. DESIGN--Cost-effectiveness analysis based on cohort analytic studies previously reported and average salaries and costs of medical care in Sweden. SETTING--Adolescent males attending a primary care center for routine health checks. PARTICIPANTS--Estimates of costs and benefits are based on a cohort of 1000 adolescent males and their female contacts. INTERVENTION--Screening with enzyme immunoassay (EIA), either on leukocyte esterase (LE)--positive urine samples (LE-EIA screening) or on all urine samples (EIA screening), was compared with no screening (no treatment or contact tracing). The effects of confirming positive EIA results with a blocking assay and alternative antibiotic regimens on the outcome of the screening strategies were also evaluated. RESULTS--Compared with no screening, the LE-EIA and EIA screening strategies reduced the overall costs when the prevalence of chlamydial infection in males exceeded 2% and 10%, respectively. Enzyme immunoassay screening achieved an overall cure rate that was 12.2% to 12.6% (95% confidence interval) better, but reduced the incremental savings by at least $2144 per cured male, in comparison with LE-EIA screening. Confirmation of positive EIA results reduced the overall cost of the LE-EIA screening strategy when the prevalence of C trachomatis among males was less than 8%. Compared with a 7-day course of doxycycline, a single oral dose of azithromycin administered under supervision in the clinic improved the cure rates of both EIA and LE-EIA screening strategies by 15.1% to 16.3% and 11.2% to 12.0%, respectively, while reducing the corresponding overall costs by 5% and 9%, respectively, regardless of the prevalence of chlamydial infection in males. CONCLUSION--The use of LE-EIA screening combined with treatment of positive cases with azithromycin was the most cost-effective intervention strategy focusing on asymptomatic male carriers of C trachomatis. Positive EIA results should be confirmed when screening low-risk populations.
Notes
Comment In: JAMA. 1993 Nov 3;270(17):2097-88411579
PubMed ID
8411572 View in PubMed
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The impact of switching to polymerase chain reaction for the diagnosis of Chlamydia trachomatis infections in women.

https://arctichealth.org/en/permalink/ahliterature185062
Source
Can J Public Health. 2003 May-Jun;94(3):229-32
Publication Type
Article
Author
Kevin R Forward
Author Affiliation
Department of Pathology, Dalhousie University, Halifax, Nova Scotia. kevin.forward@cdha.nshealth.ca
Source
Can J Public Health. 2003 May-Jun;94(3):229-32
Language
English
Publication Type
Article
Keywords
Chlamydia Infections - diagnosis
Chlamydia trachomatis - isolation & purification
Female
Humans
Immunoenzyme Techniques - economics
Nova Scotia
Polymerase Chain Reaction - economics
Abstract
We noted a marked increase in Chlamydia trachomatis (CT) infections in the Capital Health Region of NS coincident with substitution of a PCR for an enzyme immunoassay (EIA). We reviewed our experience to determine the cost of switching and the impact on the number of new infections diagnosed.
Information on the number of EIA and PCR tests performed on women was retrieved from an abstracted laboratory information database. We examined records of testing performed between April 1998 and December 2001. Prior to June 2001, all genital swabs were tested using the MicroTrak, II Chlamydia EIA and confirmed by direct fluorescence examination. After July 2001, genital swabs were tested using the COBAS AMPLICOR C. trachomatis test.
During the study period, 62,288 EIA tests were performed on specimens submitted; 2,061 (3.33%) were positive. In the six months when testing was performed by the PCR method, 9,559 PCR tests were performed, 463 (4.84%) were positive; 46% increase. In the three years before PCR testing was implemented, an average of 1,626 specimens were submitted monthly. An average of 54 tests were positive (3.3%). The cost for each positive detected by PCR was 208 dollars Cdn and 226 dollars by EIA.
The switch to PCR for the diagnosis of CT produced a marked increase in the number of chlamydia infections diagnosed. The recent increase in the number of reported CT cases in Canada may be due in large part to more sensitive tests. Surprisingly, the cost of each positive test by PCR was 18 dollars Cdn less than that of the EIA.
PubMed ID
12790500 View in PubMed
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Nonutility of routine testing of stool for ova and parasites in a tertiary care Canadian centre.

https://arctichealth.org/en/permalink/ahliterature124870
Source
Can J Microbiol. 2012 May;58(5):653-9
Publication Type
Article
Date
May-2012
Author
Mahmoud Mosli
Jamie Gregor
Nilesh Chande
Robert Lannigan
Author Affiliation
London Health Sciences Centre, Department of Medicine, London, ON N6A 5W9, Canada. ma7mos@yahoo.com
Source
Can J Microbiol. 2012 May;58(5):653-9
Date
May-2012
Language
English
Publication Type
Article
Keywords
Ambulatory Care
Animals
Cryptosporidium - isolation & purification
Diarrhea - diagnosis - parasitology
Entamoeba - isolation & purification
Feces - parasitology
Giardia lamblia - isolation & purification
Humans
Immunoenzyme Techniques - economics
Microscopy
Ontario
Parasite Egg Count
Parasitic Diseases - diagnosis
Predictive value of tests
Sensitivity and specificity
Abstract
In many clinical situations, stool examinations for ova and parasites (O&P) are routine in the work-up of patients with acute or chronic diarrhea. Frequently, these tests are found to be negative for pathogens. The purpose of this study was to examine the diagnostic yield of routine stool testing for O&P in a Canadian tertiary care centre and to estimate the potential clinical benefit of a positive result.
All stool samples sent to the central microbiology laboratory at London Health Sciences Centre were reviewed over a 5-year period ending January 2010. Initial screening was done by direct antigen testing using an enzyme immunoassay (EIA) technique followed by direct microscopy for negative results where there was a high index of suspicion and for positive results to rule out any concurrent parasites not included in the EIA kit. Pathogens identified were categorized and their potential susceptibility to metronidazole was estimated. No clinical data were available, as this was purely a utilization study.
A total of 5812 stool tests were ordered. Of these, 5681 (97.7%) were completed. The most common reasons for an incomplete test were sample leakage (n = 38) and use of the incorrect collection kit (n = 32). Direct microscopy identified white blood cells in 17% of patients with positive testing. The most common pathogen was Giardia lamblia , which was detected in 45/83 (54%) of positive specimens. Entamoeba histolytica/Entamoeba dispar was identified in 16/83 (19%) and Cryptosporidium spp. in 10/83 (12%) of positive specimens. Microorganisms not thought to be pathogenic were identified in 7/83 (8%). Direct laboratory costs independent of labor were estimated at $1836 per clinically significant organism identified. Of the 77 specimens positive for pathogenic organisms, 62 (81%) were likely to be sensitive to treatment with metronidazole.
In a tertiary care centre, the diagnostic yield of routine testing of stool for O&P during the evaluation of patients with acute or chronic diarrhea is low. Most clinically significant positive results should be responsive to metronidazole, but empirical treatment is not encouraged. Strategies to identify patients with a higher likelihood of harboring pathogenic parasites and consideration of empiric metronidazole therapy for patients at highest risk merit further research.
PubMed ID
22540249 View in PubMed
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Validity and cost-effectiveness of the Gonozyme test in the diagnosis of gonorrhea.

https://arctichealth.org/en/permalink/ahliterature237524
Source
CMAJ. 1986 Jan 15;134(2):121-4, 146
Publication Type
Article
Date
Jan-15-1986
Author
E. Thomas
S D Scott
I. Grefkees
G. Hession
R. Pollock
T. Martin
W. Albritton
Source
CMAJ. 1986 Jan 15;134(2):121-4, 146
Date
Jan-15-1986
Language
English
Publication Type
Article
Keywords
Canada
Cost-Benefit Analysis
Costs and Cost Analysis
Female
Gonorrhea - diagnosis - epidemiology
Humans
Immunoenzyme Techniques - economics - standards
Male
Neisseria gonorrhoeae - isolation & purification
Specimen Handling
Abstract
Although bacterial culture is considered to provide the most definitive diagnosis of gonorrhea, it has limitations when specimens must be transported long distances. A study was carried out to evaluate the validity and cost-effectiveness of an alternative method of diagnosing gonorrhea, the Gonozyme test, a commercially available enzyme immunoassay. Urogenital specimens from 100 men and 100 women with symptoms suggestive of or a history of exposure to gonorrhea were tested for the presence of Neisseria gonorrhoeae by means of bacterial culture and for gonococcal antigen with the Gonozyme test. The specimens from the men were also examined by means of microscopy of Gram-stained smears. The sensitivity and specificity of the Gonozyme test with reference to culture results were 95.6% and 97.4% respectively in the men and 84.2% and 98.7% in the women. The predictive value of a positive result was 91.6% in the men and 94.1% in the women, and the predictive value of a negative result 98.6% in the men and 96.3% in the women. The cost-effectiveness of the Gonozyme test was higher than that of bacterial culture in this population, which had a high prevalence rate of gonorrhea (23% in the men and 19% in the women). The Gonozyme test would be an adequate alternative to culture for the diagnosis of gonorrhea and contact tracing in areas far from diagnostic laboratories.
Notes
Cites: J Infect Dis. 1982 Aug;146(2):275-96809844
Cites: Sex Transm Dis. 1982 Apr-Jun;9(2):63-96808674
Cites: J Clin Microbiol. 1984 Mar;19(3):347-506425355
Cites: Am J Clin Pathol. 1984 Oct;82(4):461-56433697
Cites: Br J Vener Dis. 1980 Dec;56(6):390-36778588
Cites: JAMA. 1976 Jan 5;235(1):49-51946002
Cites: J Med Microbiol. 1984 Oct;18(2):271-66436492
Cites: Sex Transm Dis. 1980 Oct-Dec;7(4):183-76779390
Cites: J Clin Microbiol. 1984 Jan;19(1):57-96418763
PubMed ID
3080213 View in PubMed
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