Comparison of direct inoculation and Copan transport systems for isolation of Neisseria gonorrhoeae from endocervical specimens.
(25/2075)
Two commercial swab transport systems, Copan Amies gel agar with and without charcoal (Copan Diagnostics, Corona, Calif.), were compared to direct inoculation onto modified Thayer-Martin medium for detection of Neisseria gonorrhoeae in 1,490 endocervical specimens obtained from women attending a sexually transmitted disease clinic. Copan swabs were held in the transport system for 24 h at room temperature prior to inoculation onto modified Thayer-Martin medium. All cultures were incubated at 35 degrees C in 5% CO(2), and bacteria were identified on the basis of Gram stain, oxidase, and biochemical reactions. Copan Amies gel agar transport system without charcoal detected 77 of 81 (95%) direct inoculation culture-positive specimens, and Copan Amies gel agar transport system with charcoal detected 53 of 56 (95%) directly inoculated culture-positive specimens. Copan Amies gel agar without charcoal inoculated after 6 h supported growth of 56 (98%) positive cultures out of only 55 directly inoculated culture-positive specimens. This study demonstrates that Copan swabs represent a reasonable alternative, providing convenience, low cost, and ease of use while still maintaining a satisfactory recovery rate of N. gonorrhoeae from clinical specimens, if specimens can be inoculated onto selective media within a relatively short time period not involving overnight shipment. (+info)
Ability of the digene hybrid capture II test to identify Chlamydia trachomatis and Neisseria gonorrhoeae in cervical specimens.
(26/2075)
The Digene Hybrid Capture II (HCII CT/GC) test is a combination test designed to detect Chlamydia trachomatis and Neisseria gonorrhoeae in a single specimen. It is a nucleic acid hybridization test which uses signal amplification to increase sensitivity. We compared its performance to that of culture on cervical specimens from 1,370 women. Direct fluorescent-antibody assay was used to resolve discrepant results for C. trachomatis. Samples were collected with a proprietary cervical brush or with endocervical swabs. The HCII CT/GC test proved to be sensitive and specific in detecting these organisms. Compared to N. gonorrhoeae culture, it had a sensitivity of 93% (87/94) and a specificity of 98.5% (1,244/1,263). Compared to C. trachomatis culture, the sensitivity was 97.7% (129/132) and specificity was 98.2% (1,216/1,238). Testing of some specimens with discrepant results by PCR suggested that the test would actually prove to be even more specific if it were compared to a nucleic acid amplification test (NAAT). The sensitivity of C. trachomatis culture was somewhat less, at 88.6% (117/132). The endocervical brush appeared to be better than Dacron swabs for collecting specimens. The HCII CT/GC test offers an attractive format that allows simultaneous detection of C. trachomatis and N. gonorrhoeae with a single specimen. An initial positive result is followed by repeat tests with probes to identify chlamydiae or gonococci. This test is more sensitive than C. trachomatis culture and is at least as sensitive as culture for gonococci. It deserves further evaluation and comparison with NAATs and may well offer an attractive alternative for diagnosis and screening of these infections. (+info)
The characteristics of false negative cervical smears--implications for the UK cervical cancer screening programme.
(27/2075)
OBJECTIVE: To accurately determine whether there are any features of an abnormal cervical smear that predispose to the production of a false negative report, in order to gain insight into why false negative reports are issued, and to establish whether there are steps that can be taken to reduce them. DESIGN: A quantitative retrospective analysis using the AxioHOME microscope of the number, size, and spatial distribution of abnormal cells in a set of 50 slides comprising a mixture of false negative and true positive cervical smears. SETTING: Five different cytology laboratories in the United Kingdom. RESULTS: False negative smears were found to be quantitatively different from true positive smears. They contained significantly fewer abnormal cells (median number of abnormal cells for false negatives = 173, median number of abnormal cells for true positives = 1712; p < 0.004), and these were more likely to be unevenly distributed on the slide. It was possible to predict with a high degree of accuracy whether a smear was a false negative by analysing number and distribution alone (kappa = 0.57). CONCLUSIONS: False negatives are quantitatively different from true positive cervical smears. This has important implications for quality assurance in the UK cervical screening programme. More consideration needs to be given to the effectiveness of existing quality assurance measures, which need to be tailored to the preferential detection of this type of abnormal cervical smear. (+info)
Type-specific persistence of human papillomavirus DNA before the development of invasive cervical cancer.
(28/2075)
BACKGROUND: Infection with the human papillomavirus (HPV) has been established as a cause of cervical cancer, but the association between a positive test for HPV DNA and the risk of the subsequent development of invasive cervical cancer is unknown. METHODS: In a study of women who participated in a population-based screening program for cancer of the cervix in Sweden from 1969 to 1995, we compared the proportion of normal cervical smears (Pap smears) that were positive for HPV DNA among 118 women in whom invasive cervical cancer developed an average of 5.6 years later (range, 0.5 month to 26.2 years) with the proportion of HPV DNA-positive smears from 118 women who remained healthy during a similar length of follow-up (controls). The control women were matched for age to the women with cancer, and they had had two normal Pap smears obtained at time points that were similar to the times of the baseline smear and the diagnosis of cancer confirmed by biopsy in the women with cancer. RESULTS: At baseline, 35 of the women with cancer (30 percent) and 3 of the control women (3 percent) were positive for HPV DNA (odds ratio, 16.4; 95 percent confidence interval, 4.4 to 75.1). At the time of diagnosis, 80 of the 104 women with cancer for whom tissue samples were available (77 percent) and 4 of the 104 matched control women (4 percent) were positive for HPV DNA. The HPV DNA type was the same in the base-line smear and the biopsy specimen in all of the women with cancer in whom HPV DNA was detected at base line. None of the control women had the same type of HPV in both smears. CONCLUSIONS: A single positive finding of HPV DNA in a Pap smear confers an increased risk of future invasive cervical cancer that is positive for the same type of virus as identified earlier. (+info)
Serum carotenoids and vitamins and risk of cervical dysplasia from a case-control study in Japan.
(29/2075)
The relationships between risk of cervical dysplasia and dietary and serum carotenoids and vitamins were investigated in a case-control study. Cases were 156 women who attended Papanicolaou test screening in nine institutes affiliated with Japan Study Group of Human Papillomavirus (HPV) and Cervical Cancer and had cervical dysplasia newly histologically confirmed. Age-matched controls were selected from women with normal cervical cytology attending the same clinic. Blood sample and cervical exfoliated cells were obtained for measuring serum retinol, alpha-carotene, beta-carotene, zeaxanthin/lutein, cryptoxanthin, lycopene and alpha-tocopherol and for HPV detection. Higher serum level of alpha-carotene was significantly associated with decreased risk of cervical dysplasia after controlling for HPV infection and smoking status (odds ratio (OR) = 0.16, 95% confidence interval (CI) 0.04-0.62 for the highest as compared with the lowest tertile). Decreased risk for the highest tertile of serum lycopene (OR = 0.28) was marginally significant. Decreased risks observed for the highest tertiles of beta-carotene (OR = 0.65) and zeaxanthin/lutein (OR = 0.53), were not statistically significant. (+info)
Reliable high risk HPV DNA testing by polymerase chain reaction: an intermethod and intramethod comparison.
(30/2075)
BACKGROUND: The development of a reproducible, sensitive, and standardised human papillomavirus (HPV) polymerase chain reaction (PCR) test is required to implement HPV testing in cervical cancer screening programmes and for triaging women with mild to moderate dysplasia. AIMS: To determine the intermethod agreement between different GP5+/6+ and MY09/11 PCR based protocols for the detection and typing of high risk (HR) HPV DNA in cervical smears and to assess the intramethod reproducibility of the GP5+/6+ PCR enzyme immunoassay (EIA) for HR-HPV detection. METHODS: For the intermethod comparison, crude aliquots of 20 well characterised cervical smears comprising five HPV negative samples, and six and nine samples containing single and multiple HPV infections, respectively, were coded and sent from reference laboratory (A) to three other laboratories. One of these (laboratory B) used the GP5+/6+ PCR-EIA and was provided with standard protocols. Another laboratory (C) used GP5+/6+ PCR combined with sequence analysis and type specific PCR, whereas two laboratories (D and E) used MY09/11 PCR followed by restriction fragment length polymorphism (RFLP) analysis for the detection and typing of HR-HPV. The intramethod agreement of GP5+/6+ PCR-EIA was analysed in a subsequent study with four other laboratories (F to I) on crude aliquots of 50 well characterised cervical smears, consisting of 32 HR-HPV positive and 18 HPV negative samples. Standardised protocols, primers, and probes were also provided by the reference laboratory for HR-HPV detection. RESULTS: In the intermethod comparison, pairwise agreement of the different laboratories with reference laboratory A for the detection of HR-HPV varied between 75% and 100% (kappa values: 0.5 to 1). Typing data revealed a broader range in pairwise agreement rates between 32% and 100%. The highest agreement was found between laboratories A and B using standardised protocols and validated reagents. In the intramethod evaluation, pairwise comparison of the laboratories F to I with reference laboratory A revealed excellent agreement rates from 92% to 100% (kappa values: 0.88 to 1.0) with an overall sensitivity of 97.5% (195/200) and specificity of 99.5% (199/200). CONCLUSIONS: The detection of HR-HPV as a group is highly reproducible with GP5+/6+ PCR-EIA provided that standardised protocols and validated reagents are used. (+info)
A social science perspective on screening for Chlamydia trachomatis.
(31/2075)
A recent report from the chief medical officer's expert advisory group on Chlamydia trachomatis has recommended the setting up of two pilot projects to assess the feasibility of introducing a national chlamydia screening programme. In addition to screening all symptomatic individuals and all attenders at genitourinary medicine clinics, the report recommends opportunistic screening of sexually active young women and women at high risk of infection, who are attending either general practice or family planning clinics. The success of any new screening programme depends on a wide variety of factors, not least the acceptability of such screening to its target population. In recent years, social scientists have made significant contributions to the understanding of the psychological factors which facilitate or inhibit uptake of screening services. The aim of this report is to discuss briefly the contribution social scientists could make to the chlamydia screening programme in the United Kingdom. In particular, the possible effects of screening for a stigmatized condition such as a sexually transmitted infection are explored. (+info)
Cervical cytology: are national guidelines adequate for women attending genitourinary medicine clinics?
(32/2075)
OBJECTIVES: To study whether all women attending a genitourinary medicine (GUM) clinic warrant a cervical smear as part of a routine screen for infection, or whether this "at risk" population is adequately covered by the national screening programme. METHODS: A cervical smear and a screen for sexually transmitted infections (STI) were taken from 900 women attending a GUM clinic between May 1996 and April 1997. RESULTS: Of 812 smears available for analysis, 613 (75.5%) were normal, 176 (21.7%) were mildly abnormal, and 23 (2.8%) were moderately or severely abnormal. In the absence of an STI there was a 14% (37/273) risk of having an abnormal cervical smear. In the presence of cervicitis the risk was 26% (22/84) and with genital warts the risk was 34% (75/215). CONCLUSION: The national screening programme guidelines for cervical cytology should be followed in the GUM clinic. There is no benefit in performing extra smears outside the programme nor in adopting a policy of universal screening. (+info)