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PubMed1981

Representativeness of a muscle biopsy specimen for the whole muscle.

To investigate whether the muscle fibre area and the proportion of fibre types in a biopsy specimen are representative of the muscle, seven specimens from the anterior tibial muscle were compared with seven necropsy specimens including the whole cross-sectioned anterior tibial muscle. The fibre area of the transverse section differed greatly between biopsy and necropsy specimens, and also between different regions of the necropsy specimens, probably owing to different degrees of muscle fibre contraction. Relative measures, the coefficient of variance for the mean fibre area and the differences in size between type I and type II fibres, proved to be reliable. The proportion of fibre types varied greatly between adjacent fascicles and in different regions of the necropsy specimens. The mean proportion of type II fibres can vary from 7-30% in two biopsies from the same muscle. Great caution is therefore recommended when the proportion of fibre types in a biopsy specimen is assumed to be valid for the proportion of fibre types in the whole muscle: specimens must be taken from several sites.

Adolescent↗
PubMedDate not supplied

Changes in proportion of canine urinary calculi composed of calcium oxalate or struvite in specimens analyzed from 1981 through 2001.

The objective of this report was to characterize 20-year changes in proportion of calcium oxalate (CaOx) calculi and struvite calculi in dogs, and associations with breed, age, and sex. In this retrospective study, results of analysis of urinary calculi from dogs were reviewed for specimens received between July 1, 1981, and December 31, 2001. Breed, sex, age, year of submission of the specimen, and mineral type(s) were analyzed statistically. CaOx or Struvite or both were contained in 18,966 of 20,884 (91%) specimens. For both sexes, a 20-year statistically significant increase was observed in the proportion of calculus specimens that contained CaOx. The increase in this proportion was greater in females (1% to 31%) than in males (18% to 82%). From 1998 to 2001, when proportions may have plateaued, the odds of specimens containing CaOx were markedly higher in 18 breeds, markedly lower in 5 breeds, and not significantly different in 13 breeds compared with crossbreds. For both sexes, a 20-year statistically significant decrease was observed in the proportion of calculus specimens that contained struvite. This decrease in proportion was greater for males (79-16%) than for females (97-68%). From 1998 to 2001, when proportions plateaued, the odds of calculi containing struvite were markedly lower in 20 breeds, markedly higher in 1 breed, and not significantly different in 15 breeds when compared with crossbreds. Breed, age, and sex were associated statistically with CaOx or struvite urolithiasis. In conclusion, there appears to have been a long-term increase in the proportion of specimens of canine urinary calculi that contain CaOx as well as a long-term decrease in the proportion of specimens of calculi that contain struvite for both male and female dogs. The rate of change appeared to begin leveling off in the period 1998 to 2001. The recent proportion of dogs with either CaOx- or struvite-associated urolithiasis may depend on breed, age, and sex, and on interactions among these 3 factors.

Age Factors↗
PubMed2003

Effect of specimen size and aspect ratio on the tensile properties of porcine aortic valve tissues.

The measurement of mechanical properties of biological tissues is subject to artifacts such as natural variability and inconsistency in specimen preparation. As a result, data cannot be easily compared across laboratories. To test the effects of variable specimen dimensions, we systematically modified the size and aspect ratio (AR) of porcine aortic valve tissues and measured their stiffness and extensibility. We found that: (i) as the AR of circumferential specimens increased from 1:1 to 5:1, their stiffness increased by 36% (p < 0.001) and their extensibility decreased by 21% (p < 0.001); (ii) as the AR of radial specimens increased from 0.8:1 to 4:1, their stiffness increased by 36% (p < 0.001) and their extensibility decreased by 34% (p < 0.001); (iii) as the size of circumferential specimens was reduced from 128 to 32 mm2 at fixed AR (2:1), their stiffness decreased by 6 (p = 0.05), and their extensibility increased by 17% (p < 0.001); and (iv) as the size of radial specimens was reduced from 72 to 32 mm2 at fixed AR (2:1), their stiffness decreased by 7% (p = 0.03) and their extensibility increased by 16% (p = 0.005). Thus, as specimens of constant length became narrower, they became stiffer and less extensible, and as specimens of fixed aspect ratio became smaller, they became less stiff and more extensible. Statistical models of these trends were predictive and can thus be used to integrate materials test data across different laboratories.

Animals↗
PubMed1999

[Detection of Clostridium difficile toxin A from stool specimens by an enzyme immunoassay kit].

Toxin detection from stool specimens is prerequisite for Clostridium difficile-associated diarrhea and colitis. However, in Japan only one toxin detection kit is commercially available, which requires computerized VIDAS fluorescence reader. In this study we evaluated ImmunoCard Toxin A, which is an enzyme immunoassay with a format of individual cassette and needs no special equipment to perform, by comparing with the VIDAS CDA kit. Of 61 stool specimens 12 were positive and 39 were negative by both assays, 7 were VIDAS positive-ImmunoCard negative, 2 were VIDAS invalid-ImmunoCard negative, and 1 was invalid by both assays. Stool specimens which gave inconsistent results between two assays were subjected to cell culture assay to detect toxin B and culture for C. difficile followed by testing of toxin producibility of isolates. Of 7 VIDAS positive-ImmunoCard negative specimens 5 were negative for cell culture assay and toxigenic C. difficile culture and 2 were positive for cell culture assay. By omitting 3 VIDAS invalid specimens and counting 5 specimens, which were cell culture negative but VIDAS positive, as negative and 2, which were cell culture positive and VIDAS positive, as positive, 12 of the 14 VIDAS positive specimens were ImmunoCard positive (sensitivity, 85.7%) and all 44 VIDAS negative were ImmunoCard negative (specificity, 100%). These results indicate that although in comparison with VIDAS CDA, ImmunoCard Toxin A is slightly less sensitive, ImmunoCard is a rapid, simple, and reliable C. difficile toxin A detection kit, which has the advantage of requiring no special equipment to perform and no centrifuge step, as small as 25 muL of a specimen, and as short as approximately 15 min of time to complete the whole testing.

Bacterial Toxins↗
PubMed2006

Vulvovaginal-swab or first-catch urine specimen to detect Chlamydia trachomatis in women in a community setting?

Screening for chlamydia in women is widely recommended. We evaluated the performance of two nucleic acid amplification tests for detecting Chlamydia trachomatis in self-collected vulvovaginal-swab and first-catch urine specimens from women in a community setting and a strategy for optimizing the sensitivity of an amplified enzyme immunoassay on vulvovaginal-swab specimens. We tested 2,745 paired vulvovaginal-swab and urine specimens by PCR (Roche Cobas) or strand displacement amplification (SDA; Becton Dickinson). There were 146 women infected with chlamydia. The assays detected 97.3% (95% confidence interval [CI], 93.1 to 99.2%) of infected patients with vulvovaginal-swab specimens and 91.8% (86.1 to 95.7%) with urine specimens. We tested 2,749 vulvovaginal-swab specimens with both a nucleic acid amplification test and a polymer conjugate-enhanced enzyme immunoassay with negative-gray-zone testing. The relative sensitivities obtained after retesting specimens in the negative gray zone were 74.3% (95% CI, 62.8 to 83.8%) with PCR and 58.3% (95% CI, 46.1 to 69.8%) with SDA. In community settings, both vulvovaginal-swab and first-catch urine specimens from women are suitable substrates for nucleic acid amplification tests, but enzyme immunoassays, even after negative-gray-zone testing, should not be used in screening programs.

Adolescent↗
PubMed1979

Fluorescent antibody test kit for rapid detection and identification of members of the Bacteroides fragilis and Bacteroides melaninogenicus groups in clinical specimens.

The Fluoretec fluorescent antibody test kit (Pfizer Inc., New York, N.Y.), developed for the rapid detection of members of the Bacteroides fragilis and B. melaninogenicus groups, was evaluated by testing 58 stock cultures and 76 clinical specimens. The test reagents detected 100% of 40 B. fragilis and B. thetaiotaomicron stock culture strains, although only 22% of 18 B. vulgatus, B. distasonis, and B. ovatus strains showed positive fluorescence. The 76 clinical specimens were evaluated by examining fluorescent antibody-stained smears of 49 specimens of purulent material and smears of 27 blood cultures which were positive for gram-negative bacilli by Gram stain or subculture. The fluoretec reagent detected members of the B. fragilis group in 28 (97%) of the 29 specimens of purulent material and all (100%) of the 16 blood cultures in which these anaerobes were demonstrated by culture. Overall, the Fluoretec reagent detected members of B. fragilis group in 44 (98%) of the 45 clinical specimens which were shown by culture to contain these anaerobes. Two of the 76 clinical specimens gave positive fluorescence for members of the B. fragilis group but failed to yield these organisms by culture. Members of the B. melaninogenicus group were detected by culture in 15 specimens and in each case their presence was demonstrated by the Fluoretec reagent. No members of the B. melaninogenicus group were isolated from five clinical specimens that gave positive fluorescence with the B. melaninogenicus reagent.

Anaerobiosis↗
PubMed1987

Fluorescence detection of Cryptosporidium oocysts in human fecal specimens by using monoclonal antibodies.

With the discovery that the coccidian parasite Cryptosporidium sp. can cause severe symptoms in humans, implementation of many diagnostic techniques rapidly followed. The infection is self-limiting in patients with normal immune systems but chronic in the immunosuppressed patient. With the eventual development and use of therapeutic agents, it will become very important to find Cryptosporidium sp., even in low numbers, in fecal specimens. Production of a highly specific and sensitive antibody by use of cloning techniques has provided another diagnostic tool. Formalinized positive human fecal specimens (n = 99) and negative specimens (n = 198), of which 115 contained yeastlike fungi and other organisms, were tested in blind trials by use of a monoclonal antibody. Sensitivity was 100% with 3- to 4+ fluorescence on all cryptosporidial oocysts, both in light and heavy infections. The organisms were round and easily visible (4 to 6 micron), showing apple-green to yellow fluorescence against a dark background free of nonspecific fluorescence. Specificity was also 100% with all 99 positive Cryptosporidium sp. specimens exhibiting fluorescence and all 198 negative specimens showing no fluorescence. All positive and negative specimens were previously confirmed by the hot modified acid-fast technique. However, seven specimens previously considered negative by this acid-fast method were positive by the monoclonal antibody technique. These specimens were confirmed as positive, after extensive examination of additional smears prepared by the modified hot acid-fast method revealed rare organisms, emphasizing the increased sensitivity of the monoclonal antibody technique. Since acid-fast stains do not always consistently stain all oocysts, the increased sensitivity of the monoclonal reagent provides an excellent screening method.

Antibodies, Monoclonal↗
PubMed1988

Cost containment of formalin-preserved stool specimens for ova and parasites from outpatients.

Three individual formalinized stool specimens from each of 123 patients were pooled and examined for ova and parasites. Results obtained from the pooled specimens were compared with those obtained with the three individual specimens used to make the pooled specimens. Of 123 sets examined, 92 were negative and 31 were positive for ova and parasites. The pooled specimens were positive and all individual specimens were negative eight times, whereas the pooled specimens were negative and the individual specimens were positive twice. The data indicated that the pooled system is a useful and economical method of screening for ova and parasites.

Animals↗
PubMed1989

Evaluation of the Abbott TESTPACK RSV enzyme immunoassay for detection of respiratory syncytial virus in nasopharyngeal swab specimens.

The Abbott TESTPACK RSV assay (Abbott Laboratories, North Chicago, Ill.), a rapid (20-min) enzyme immunoassay, was compared with culture and direct immunofluorescence (DFA) of nasopharyngeal cells for the detection of respiratory syncytial virus (RSV) in nasopharyngeal swab specimens. Nasopharyngeal swab specimens, collected from 234 infants, were placed in viral transport medium. Portions of specimen in transport medium were used for each test. Of 234 specimens, 70 (30%) were culture positive, 103 (44%) were DFA positive, 107 (46%) were culture or DFA positive, and 112 (48%) were TESTPACK RSV positive. Of 19 specimens positive by TESTPACK RSV but negative by culture or DFA, 15 were positive by the blocking assay. A total of 122 specimens were culture, DFA, or blocking assay positive; TESTPACK RSV detected 108 specimens (sensitivity, 89%). The specificity, positive predictive value, and negative predictive value of TESTPACK RSV as compared with those of culture, DFA, and the blocking assay were 96, 96, and 89%, respectively. By comparison, the sensitivity, specificity, positive predictive value, and negative predictive value of combined culture and DFA were 88, 100, 100, and 88%, respectively. TESTPACK RSV is a rapid and reliable enzyme immunoassay for the direct detection of RSV antigen in nasopharyngeal swab specimens.

Fluorescent Antibody Technique↗
PubMed1990

Detection of verotoxin in stool specimens.

A total of 132 fecal specimens containing verotoxin (VT) were subjected to counter-current immunoelectrophoresis (CIE). Of these, 113 (85.6%) were found to be positive by CIE. Another 71 stool specimens containing E. coli serogroup O157 but with flagellar antigens other than H7 were tested for verotoxin by CIE. These stool specimens were negative for VT on Vero cell monolayers. Of these 71 stool specimens, 6 (8.5%) gave positive tests for verotoxin by CIE. Forty stool specimen filtrates which were negative for VT (negative controls) were also subjected to CIE. One of these stool specimen filtrates gave a line of precipitation by CIE. The specificity of the CIE test was 93.7%, and the sensitivity was 85.6%. False-positive results may have been due to an antibody component against the somatic antigen (O157) in the antitoxin used; this is a limitation of the CIE test. In a related evaluation, 302 stool specimen filtrates containing VT were retested with Vero cell suspension cultures in microdilution plates. Of these, 281 stool specimen filtrates showed cytotoxic effects within 24 h, while the remaining 21 filtrates showed the effects within 48 h. The use of Vero cell suspension culture is as reliable as the use of Vero cell monolayers and provides detection of verotoxin 24 to 48 h sooner.

Animals↗
PubMed1990

Comparison of four methods for rapid detection of Pneumocystis carinii in respiratory specimens.

Four stains for the detection of Pneumocystis carinii in respiratory specimens were compared for sensitivity, specificity, preparation time, and ease of interpretation. One hundred specimens were collected. Of these, 50 were induced sputum specimens and 50 were bronchoalveolar lavage fluid. All specimens were stained with Diff-Quik (DQ) (a modified Giemsa stain), a quick silver stain, and direct and indirect immunofluorescence stains. A positive specimen was defined as any smear positive by two or more of the methods. Fifty-eight percent of specimens were positive. Seventy-four percent of the sputum specimens and 42% of the bronchoalveolar lavages were positive. The sensitivities for detection of P. carinii in sputum were 92% with silver stain, 97% with direct immunofluorescence assay (DFA), 97% with indirect immunofluorescence assay (IFA), and 92% with DQ. The sensitivities for detection in bronchoalveolar lavage were 86% with silver stain, 90% with DFA, 86% with IFA, and 81% with DQ. Preparation times varied from 90 min for the silver stain and IFA to 3 min for DQ. Costs of the tests varied from $1.50 per slide for DQ to $10.00 per slide for the silver stain and DFA. Reading times varied from 10 to 30 min for the silver stain and DQ to less than 5 min for the immunofluorescence assays. We conclude that all of these tests are viable options for the clinical laboratory, and the choice will be influenced by factors such as clinical volume, ability to batch specimens, and expertise of technological support. A reasonable option may be to use the quick and inexpensive DQ as a screening test and to confirm negative smears with a more sensitive assay.

Bacteriological Techniques↗
PubMed1996

Multiplex PCR-based assay for detection of Bordetella pertussis in nasopharyngeal swab specimens.

A multiplex PCR-based assay was developed for the detection of Bordetella pertussis in nasopharyngeal swab specimens. The assay simultaneously amplified two separate DNA targets (153 and 203 bp) within a B. pertussis repetitive element and a 438-bp target within the beta-actin gene of human DNA (PCR amplification control). PCR products were detected by a sensitive and specific liquid hybridization gel retardation assay. A total of 496 paired nasopharyngeal swab specimens were tested by both the PCR-based assay and culture. Although 30 (6%) of the specimens inhibited the amplification of the beta-actin target, in all 29 specimens studied, the inhibition disappeared on repeat testing or was easily overcome with a 1:8 dilution or less of specimen digest. Of the 495 specimen pairs yielding a final evaluable result by the PCR-based assay, 19.0% were positive by the PCR-based assay, whereas 13.9% were positive by culture (P < 0.0001). After resolving the PCR-positive, culture-negative results by testing an additional aliquot from these specimens by the multiplex PCR-based assay, the PCR-based assay had a sensitivity and specificity of 98.9 and 99.7%, respectively, compared with values of 73.4 and 100%, respectively, for culture. In comparison with patients with culture-confirmed pertussis, those with PCR-positive, culture-negative results were older and more likely to have had prolonged cough, immunization with pertussis vaccine, or treatment with erythromycin. This multiplex PCR-based assay is substantially more sensitive than culture and identifies specimens that contain inhibitors of PCR.

Actins↗
PubMed1996

Comparison of the Roche AMPLICOR MYCOBACTERIUM assay and Digene SHARP Signal System with in-house PCR and culture for detection of Mycobacterium tuberculosis in respiratory specimens.

Two commercial primer kits and detection systems, the Roche AMPLICOR MYCOBACTERIUM test and the Digene primer-probe kit with the SHARP Signal System, were compared to in-house PCR as well as standard culture techniques. For the 27 culture-positive specimens, the Roche AMPLICOR MYCOBACTERIUM test detected 20 specimens, the Digene system detected 19, and in-house PCR detected 21. Of the 86 culture-negative specimens, 13 were positive by the Roche AMPLICOR MYCOBACTERIUM test, 16 were positive by the Digene system, and 21 were positive by in-house PCR. When clinical situations were evaluated, 11 of 13 culture-negative Roche AMPLICOR MYCOBACTERIUM test-positive specimens, 10 of 16 culture-negative Digene system-positive specimens, and 13 of 21 culture-negative-in-house PCR-positive specimens were diagnosed as true-positive specimens. The sensitivities of Roche AMPLICOR MYCOBACTERIUM test, the Digene system, and in-house PCR were 73.81, 69.05, and 80.95%, and the specificities were 97.18, 91.55 and 88.73%, respectively. The positive predictive values were 93.94, 82.86, and 80.95%, and the negative predictive values were 86.25, 83.33, and 88.73%, respectively. For the commercial kits, the Roche AMPLICOR MYCOBACTERIUM test seems to be more sensitive and specific than the Digene system. However, the Roche AMPLICOR MYCOBACTERIUM test cannot be used on nonrespiratory specimens.

Bacteriological Techniques↗
PubMed1997

Differentiation of Helicobacter pylori strains directly from gastric biopsy specimens by PCR-based restriction fragment length polymorphism analysis without culture.

Recent studies have shown the usefulness of PCR-based restriction fragment length polymorphism (RFLP) analysis for differentiating Helicobacter pylori strains isolated by culture. For this study, a PCR-based RFLP assay was developed for directly typing H. pylori strains from gastric biopsy specimens. Nineteen gastric biopsy specimens obtained from patients undergoing endoscopy for gastrointestinal complaints were cultured for isolation of H. pylori. Genomic DNA preparations from these gastric biopsy specimens and the corresponding H. pylori isolates were tested by our PCR-based RFLP assay. The 1,179-bp H. pylori DNA fragments amplified by the PCR assay were digested with the restriction enzymes HhaI, MboI, and AluI and analyzed by agarose gel electrophoresis. HhaI, MboI, and AluI digestion produced 11, 10, and 6 distinguishable digestion patterns, respectively, from the 19 H. pylori isolates tested and generated 13, 11, and 6 different patterns, respectively, from the 19 gastric biopsy specimens. The patterns from 13 of the 19 gastric biopsy specimens matched those of the H. pylori isolates from the corresponding patients. The patterns from the remaining six biopsy specimens appeared to represent infection by two strains of H. pylori; the pattern of one strain was identical to that of the isolate from the corresponding patient. By combining all the restriction enzyme digestion patterns obtained by using HhaI, MboI, and AluI, we observed 19 distinct RFLP patterns from the 19 specimens. The results suggest that the PCR-based RFLP analysis method may be useful as a primary technique to identify and distinguish H. pylori strains directly from gastric biopsy specimens without culture of the organisms.

Bacterial Typing Techniques↗
PubMed1997

Evaluation of the semiautomated Abbott LCx Mycobacterium tuberculosis assay for direct detection of Mycobacterium tuberculosis in respiratory specimens.

Five hundred twenty processed respiratory specimens from 326 patients received for the diagnosis of tuberculosis or other mycobacterial infections were tested by means of the LCx Mycobacterium tuberculosis Assay from Abbott Laboratories, which uses ligase chain reaction technology for the direct detection of M. tuberculosis complex in respiratory specimens. The results of the LCx M. tuberculosis Assay were compared with the results of culture and staining techniques. After a combination of culture results and the patient's clinical data, a total of 195 specimens were collected from 110 patients who were positively diagnosed as having pulmonary tuberculosis. Twenty-three of these 195 specimens which corresponded to 10 patients with a history of pulmonary tuberculosis (TB) and anti-TB treatment ranging from 1 to 6 months were culture negative. The other 172 specimens were culture positive for M. tuberculosis. With an overall positivity rate of 37.5% (195 of 520 specimens), the sensitivity, specificity, and positive and negative predictive values were 90.8, 100, 100, and 94.7%, respectively, for the LCx M. tuberculosis Assay; 88.2, 100, 100, and 93.4%, respectively, for culture; and 82.6, 92, 72.9, and 97.6%, respectively, for acid-fast staining. For 161 specimens (82.6%) from patients smear positive for the disease and 34 specimens (17.4%) from patients smear negative for the disease, the sensitivity values for the LCx M. tuberculosis Assay were 98.8 and 53%, respectively. There were no statistically significant differences in the sensitivities and specificities between the LCx M. tuberculosis Assay and culture (P > 0.05). Conclusively, the LCx M. tuberculosis Assay has proved to have an acceptable sensitivity and a high specificity in detecting M. tuberculosis and has the potential of reducing the diagnosis time to an 8-h working day.

Bacterial Typing Techniques↗
PubMed1998

Comparative evaluation of the new gen-probe Mycobacterium tuberculosis amplified direct test and the semiautomated abbott LCx Mycobacterium tuberculosis assay for direct detection of Mycobacterium tuberculosis complex in respiratory and extrapulmonary specimens.

Two commercial assays that detect Mycobacterium tuberculosis complex (MTB) in clinical specimens by rRNA target amplification (AMTDII) and ligase chain reaction (LCx) were evaluated. The tests were applied to 457 respiratory (n = 273) and extrapulmonary (n = 184) specimens collected from 357 patients. The results were compared with those of acid-fast staining and culture. The combination of culture and clinical diagnosis was considered to be the "gold standard." Seventy specimens were from patients with pulmonary tuberculosis and 28 specimens were from patients with extrapulmonary tuberculosis. After resolution of discrepant results, the overall sensitivities, specificities, and positive and negative predictive values for respiratory specimens were 92.8, 99.4, 98.5, and 97%, respectively, for AMTDII and 75.7, 98.8, 96.4, and 90.5%, respectively, for LCx. With extrapulmonary specimens, the overall sensitivities, specificities, and positive and negative predictive values were 78.6, 99.3, 95.6, and 96.2%, respectively, for AMTDII and 53.6, 99.3, 93.7, and 92.1%, respectively, for LCx. The level of agreement between AMTDII and LCx assay results was 78.2%. We conclude that although both nucleic acid amplification methods are rapid and specific for the detection of MTB in clinical specimens, AMTDII is significantly more sensitive than LCx with both respiratory (P = 0.005) and extrapulmonary (P = 0.048) specimens.

Bronchi↗
PubMed1999

Comparison of the PACE 2 assay, two amplification assays, and Clearview EIA for detection of Chlamydia trachomatis in female endocervical and urine specimens.

Screening for sexually transmitted diseases (STDs) in a greater proportion of sexually active patients has become an accepted protocol by most health care providers. The purpose of this study was to compare the current test methods for detection of Chlamydia trachomatis used at the University of South Alabama, the PACE 2 assay (Gen-Probe) and the Clearview EIA (Wampole Laboratories), with two amplification technologies, the AMP CT (Gen-Probe) and LCx (Abbott) assays. In addition, a number of demographic parameters were ascertained by asking questions at the time of examination as well as for health care provider concerns and preferences. One urine and four endocervical swab specimens were collected in random order from 787 female patients attending one of four obstetrics-gynecology clinics. Eighty-seven percent of patients had no STD-related symptoms. Patients were considered positive for C. trachomatis if three or more assays (swab and/or urine) were positive. Abbott and Gen-Probe confirmed discrepant results by alternate amplified assays. A total of 66 true-positive specimens were detected by use of the combination of endocervical swabs and urine specimens. After discrepant analysis, sensitivities for endocervical swab specimens for the EIA and the PACE 2, LCx, and AMP CT assays were 50, 81, 97, and 100%, respectively. Sensitivities for the LCx and AMP CT assays with urine specimens were 98 and 81%, respectively. The prevalence of C. trachomatis was 8.4%, as determined by amplification technology. Overall, the amplification technologies were the most sensitive methods with either swab (AMP CT assay) or urine (LCx assay) specimens. The PACE 2 assay offered the advantage of a simpler and less expensive assay with acceptable sensitivity. The clearview CT EIA, while yielding a rapid in-office result, had unacceptably low sensitivity. The wide variation in performance with amplification assays with urine specimens as reported in both this study and the literature obviates the need to clarify optimal parameters for this specimen type.

Alabama↗
PubMed2000

Increased sensitivity of the BACTEC 460 mycobacterial radiometric broth culture system does not decrease the number of respiratory specimens required for a definitive diagnosis of pulmonary tuberculosis.

The BACTEC 460 radiometric mycobacterial broth culture system has consistently demonstrated faster and increased recovery of Mycobacterium tuberculosis from respiratory specimens of patients with pulmonary tuberculosis than conventional culture methods. We thus questioned whether three sputa were still necessary to definitively diagnose pulmonary tuberculosis if the BACTEC radiometric culture system were in use. We performed a retrospective analysis of 430 sequential respiratory specimens submitted from 143 patients and from which M. tuberculosis had been recovered by in vitro culture and simultaneously assessed the diagnostic yield of acid-fast smear in this same cohort. M. tuberculosis was recovered from the first specimen for 117 (82%) of the 143 patients, from the second for 14 patients (10%; cumulative rate, 92%), and from the third for 12 patients (8%; cumulative rate, 100%). With the exception of those for bronchial brushings, recovery rates of M. tuberculosis were comparable for all respiratory specimen types (expectorated sputum, induced sputum, tracheal aspirates, bronchoalveolar lavage fluids). Only 46 (32%) of these 143 patients had acid-fast bacilli detected in smears; acid-fast bacilli were detected in the first submitted specimen for 44 patients (96%) and in the second for the remaining 2 patients (4%; cumulative rate, 100%). Culture- or smear-positive rates for sequential specimens obtained from AIDS patients were comparable to those for non-AIDS patients. Overall, the diagnostic culture yield of sequentially submitted specimens was not different from previously published studies in which the BACTEC radiometric culture system had not been used. Despite the documented enhanced ability of the BACTEC 460 radiometric mycobacterial culture system to recover M. tuberculosis more often and faster than conventional methods, three sequential respiratory specimens (regardless of type) were still necessary to definitively diagnose pulmonary tuberculosis.

Acquired Immunodeficiency Syndrome↗