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D G Ferris

Publications and source records attributed to D G Ferris.

14 recordsLinked to original sources
PubMed1992

Elementary school students' performance with two ELISA test systems.

OBJECTIVE: To examine analytic performance by previously untrained and inexperienced subjects using enzyme-linked immunosorbent assay (ELISA) tests developed for decentralized laboratories. Performance variability between tests assigned to the "simple" and "moderately complex" Health Care Financing Administration laboratory levels was evaluated. DESIGN: A nonrandomized trial of the Surecell Strep-A chorionic gonadotropin ELISA tests. Each subject processed nine unknown specimens (three negative, three weakly positive, and three strongly positive) for each ELISA test. Subjects were blinded to expected test results. SETTING: An elementary school. SUBJECTS: A convenience sample of 52 students enrolled in the sixth and seventh grades. This age group was chosen because of their ability to generally comprehend instructions and remain attentive to the testing task. INTERVENTIONS: Subjects were either self-trained by reading package insert directions or trained by a manufacturer's sales representative. MAIN OUTCOME MEASURES: Performance was measured as the percentage of correct test results for the unknown specimens. The sensitivity and specificity for each test by operator group were calculated. RESULTS: Subjects demonstrated an overall sensitivity of 97.1% and specificity of 94.7% for human chorionic gonadotropin unknown specimens and a 95.9% sensitivity and 96.8% specificity for group A streptococcus unknown specimens. No significant differences between the self-trained group and the representative-trained group were observed for either group A streptococcus or human chorionic gonadotropin tests. Performance was so high with the first specimen that improvement over time (ie, a "learning curve") could not be demonstrated. CONCLUSION: These ELISA test systems are able to achieve high levels of performance by subjects with no formal laboratory background, no previous method specific experience, and limited self-training.

Adolescent↗
PubMed1992

Colposcopy.

Explore the source record for details and available documents.

Clinical Competence↗
PubMed1992

The optimal technique for obtaining a Papanicolaou smear with the Cervex-Brush.

BACKGROUND: The Cervex-Brush (Rovers, The Netherlands; Unimar, Wilton, Conn) is a cervical cytologic sampling device used to simultaneously collect endocervical and ectocervical cells. The optimal method for using this device to collect cervical epithelial cells for a Papanicolaou smear has not been described in the medical literature. METHODS: Using the Cervex-Brush, Papanicolaou smears were collected from 516 women in a prospective randomized study to evaluate five different clockwise rotation techniques: 180 degrees rotation of the brush, 360 degrees, 720 degrees, 1080 degrees, and 1800 degrees. The Bethesda System of classifying Papanicolaou smears was used to report cytologic results. Endocervical cell presence as an indicator of smear adequacy was quantitated from 0 to 4+. RESULTS: As the number of rotations was increased, the number of endocervical cells collected also increased (P less than .05). Abnormal epithelial cells were found in 22.3% of the smears obtained by rotating the brush 1080 degrees and 1800 degrees. This was compared with abnormal cells found in 8.2%, 4.5%, and 11.5% of the smears collected by rotating the brush 180 degrees, 360 degrees, and 720 degrees, respectively (P less than .001). Two smears that identified high-grade squamous intraepithelial lesions were collected using the 1800 degrees rotation. Unsatisfactory smears were obtained in 39 (7.5%) of the 516 smears. The percentage of slides containing hemorrhagic artifact was greatest (16.4%) in the 1800 degrees rotation group, but the likelihood of the Papanicolaou smear being considered unsatisfactory was not increased (P less than .05). CONCLUSIONS: Using a clockwise 1800 degrees rotation of the Cervex-Brush to obtain a Papanicolaou smear maximized the collection of endocervical cells, detected the greatest percentage of abnormal cells, and did not statistically exceed the acceptable limit for hemorrhagic artifact.

Adolescent↗
PubMed1992

A comparison of three rapid chlamydial tests in pregnant and nonpregnant women.

BACKGROUND: The purpose of this investigation was to evaluate the performance characteristics of three rapid immunoassay tests to detect Chlamydia trachomatis cervicitis. METHODS: Endocervical samples from 506 women were evaluated using the three rapid immunoassay tests and the results were compared with those obtained by an endocervical chlamydial culture. RESULTS: The prevalence of C trachomatis cervicitis was 9.3%. Overall sensitivity and specificity of the Abbott TestPack Chlamydia test were 66.0% and 99.8%, respectively, of the Kodak Surecell Chlamydia test were 85.1% and 99.3%, respectively, and of the Unipath Clearview Chlamydia test were 85.1% and 98.5%, respectively. Pregnancy did not affect test specificity, but did influence sensitivity. The tests ranged from 5% to 22% less sensitive in nonpregnant women. CONCLUSIONS: The results of the investigation establish that the Clearview and Surecell chlamydial immunoassay tests performed well, particularly for pregnant women.

Adult↗
PubMed1992

Cryosurgical equipment: a critical review.

BACKGROUND: Cryosurgery is frequently used by family physicians to treat benign and premalignant epithelial disease. A professional medical team consisting of a practicing cryotherapist and a mechanical engineer independently critically evaluated the design, function, and performance of selected cryosurgical equipment. METHODS: Qualitative observations and quantitative measurements were performed on seven nitrous oxide cryosurgical units and one liquid nitrogen unit, representing seven manufacturers and distributors. Specific isotherm generation distributions, lateral spread of freeze and refreeze measurements, defrost intervals, recovery zone sizes, relative ease of use, and component characteristics were comparatively assessed. RESULTS: The in vitro mean lateral spread of freeze distance at 180 seconds varied between 5.8 mm for the Frigitronics CryoPlus and 4.6 mm for the Leisegang LM-900. The mean -20 degrees C isotherm generation time, measured by a thermocouple 3 mm lateral to the cryoprobe tip margin, ranged from 229 seconds for the Wallach WA-1000B to 361 seconds for the Spembly PCG 9R. Defrost times varied between 2 seconds for the Wallach WA-1000B and 320 seconds for the Brymill Mini-Cryogun. Refreeze time was quickest (36 seconds) using the GyneTech GT-1S. The mean in vitro recovery zones varied between 1.6 mm and 2.1 mm. CONCLUSIONS: This evaluation documented both differences and similarities among various cryosurgical units in terms of design, function, and performance. The Wallach, Frigitronics, and GyneTech nitrous oxide cryosurgical units demonstrated the best overall performance.

Cryosurgery↗
PubMed1991

Noninvasive detection of Chlamydia trachomatis urethritis in men by a rapid enzyme immunoassay test.

BACKGROUND: The purpose of this investigation was to evaluate the ability of a rapid enzyme immunoassay test to noninvasively detect Chlamydia trachomatis urethritis in men from a urine specimen. METHODS: Urethral samples and urine from 207 patients were evaluated. Urethral and urine sediment Gram stains, leukocyte esterase dipstick tests, and enzyme immunoassay analyses of centrifuged and uncentrifuged urine were compared with urethral C trachomatis culture. RESULTS: The prevalence of infection in this population was 10.3%. Sensitivity and specificity of the enzyme immunoassay on the centrifuged urine specimen were 70% and 96%, respectively. The positive and negative predictive values were 67% and 97%, respectively. The uncentrifuged urine enzyme immunoassay sensitivity was 35.7% and specificity was 98.9%. Leukocyte esterase test sensitivity compared with that of the Neisseria gonorrhoeae and/or C trachomatis cultures was 83.3%, and specificity was 52%. CONCLUSIONS: The rapid enzyme immunoassay clinically complemented the screening urine sediment Gram stain and the leukocyte esterase test. The judicious use of a noninvasive C trachomatis rapid enzyme immunoassay test to identify organism-specific urethritis may improve patient management of sexually transmitted disease.

Adult↗
PubMed1991

Colpophotography systems: a review.

Colpophotography and video colposcopy systems are useful for pathology documentation purposes, patient education, and colposcopy training. A wide variety of colposcopic visual media components are available to enhance routine colposcopy. Colpophotographic systems supplied by eight colposcope manufacturers were critically evaluated by a colposcopist and a medical photographer. Components were independently and objectively analyzed. Photographic examination considered color, illumination uniformity, and coverage of illumination at all possible colposcopic magnifications. Photographs were developed by a standardized technique. The investigation results clearly demonstrated variability between different colpophotographic systems. Quality colpophotography is dependent on certain colposcope features and potential modifications. Colpophotography and video colposcopy systems complement the standard colposcopic procedure.

Colposcopes↗
PubMed1991

Colposcopes: a critical review.

A multidimensional professional team consisting of a practicing colposcopist, a mechanical engineer, and a medical photographer independently critically evaluated the features of selected colposcopes. Qualitative observations and quantitative measurements were performed on 13 colposcopes representing eight manufacturers and distributors. Optical characteristics, ocular system operation, mobility and stability, relative ease of use, component characteristics, space for instrumentation, and visual illumination, uniformity, and color were comparatively assessed. The specific colposcope information provided may benefit practicing physicians or novice colposcopists who are contemplating purchasing a colposcope. The presented framework of critical feature evaluation may also facilitate the informed selection of other colposcopes not included in this selective, critical, comprehensive review.

Colposcopes↗
PubMed1990

A comparison of rapid enzyme immunoassay tests for the detection of Chlamydia trachomatis cervical infections.

Two rapid enzyme immunoassay test kits were compared with culture for the detection of Chlamydia trachomatis endocervical infections. Endocervical samples for C trachomatis culture and the two enzyme immunoassay tests were evaluated from 502 county health department and Planned Parenthood patients. The prevalence of infection in this population was 12%. Sensitivity and specificity of the Abbott TestPack Chlamydia were 51.7% and 99.5%, respectively, and of the Kodak Surecell Chlamydia were 76.7% and 98.6%, respectively. The positive and negative predictive values for TestPack were 93.9% and 93.8%, and for Surecell were 88.5% and 96.9%, respectively. Additionally, an in vitro investigation was used to evaluate whether typical office staff (physicians, nurses, medical technicians, receptionists, and radiology technicians) were able to perform competently the tests in each kit. Office personnel tested 12 dilutions of a C trachomatis stock sample or negative control sample as unknowns for each kit in the in vitro investigation. There were no differences among office staff in performance when compared for each test kit. Selective use of these enzyme immunoassay tests for high-risk patients in a family practice population that has a high prevalence of patients with C trachomatis infection may be helpful when rapid test results are required and cultures are not feasible. After appropriate training, most physician office personnel were equally able to perform the enzyme immunoassay tests evaluated.

Adult↗
PubMed1990

Test of cure for genital Chlamydia trachomatis infection in women.

Convenient, reliable tests of cure for genital chlamydial infections have not been evaluated. Cervical appearance, endocervical Gram stain, enzyme immunoassay, and culture for Chlamydia trachomatis were evaluated during a pretreatment visit and at two subsequent randomized test-of-cure visits for 64 nongravid women with endocervical C trachomatis of 3544 patients screened. There were no useful correlations between C trachomatis resolution and cervical appearance. Endocervical Gram stain was determined to be unreliable for test-of-cure use. Both C trachomatis culture and enzyme-linked immunosorbent assay (ELISA) were shown to be effective for test-of-cure evaluation. The ELISA test became reliably negative 10 days after initiation of treatment and 1 to 5 days after the clearance of viable organisms detected by culture (P = .03). Convenience and cost considerations favor antigen detection methods. This study suggests that antigen detection methods can be used for situations in which test of cure is indicated, such as therapy noncompliance, circumstances supporting reinfection, pregnancy, complicated infections, requests for psychological reassurance, and evidence of persistent cervicitis.

Chlamydia Infections↗
PubMedDate not supplied

Colposcopy practice and training in family practice residency programs.

BACKGROUND: The potential growth of colposcopy as a family medicine procedural skill is directly related to the training currently offered to family practice residents. To define whether these skills are being adequately offered to physicians who want to perform this procedure for their patients, a study was designed to investigate the current status of colposcopy practice and training in family practice residency programs. METHODS: A 16-item survey sent to 356 family practice residency directors in the United States included items concerning colposcopy practice, training, educational programs and strategies, colposcopy coordinator educational background, and colposcopic resource materials and equipment. RESULTS: Surveys were returned from 204 (57 percent) family practice residencies. Colposcopy was performed at 45 percent of the residencies that responded. Ninety-six percent of the respondents who did not perform colposcopy believed colposcopy is a procedure that should be performed by family physicians. Clinical teaching and supervision was the most common method of resident training (74 percent). Colposcopy training coordinators were usually family physicians (72 percent), primarily trained by gynecologists. Assistance with implementing a colposcopy training program was requested by 85 percent of those programs presently not performing colposcopy. CONCLUSIONS: This study indicates that there are opportunities for further development of colposcopy practice and training in family practice residencies.

Attitude of Health Personnel↗