Nucleic Acid Amplification Tests Testing Research Articles

The effect on Neisseria gonorrhoeae screening rates in an integrated clinic following the introduction of dual nucleic acid amplification tests

Sirs: We read with interest the findings of Killick et al. 1 and agree that Neisseria gonorrhoeae (GC) nucleic acid amplification testing (NAAT) can provide a valuable addition to culture for identifying GC in low prevalence settings. Following the introduction of GC NAAT into our integrated family planning (FP) and genitourinary (GU) medicine service, we evaluated whether the use of NAAT increased the rates of GC screening and of GC detection. 2 Prior to the introduction of GC NAAT, prevalence of diagnosed GC within the clinic as assessed by culture alone was 0.87%. We sought to investigate concordance between NAAT and culture when both were carried out, within this low prevalence population. Dual-testing for GC and chlamydia (CT) using Aptima Combo 2 (AC2; Gen-Probe Inc., San Diego, CA, USA) was per- formed using self-taken vaginal swabs for asymptomatic women and urine for asymptomatic men. Those patients with clinical symptoms or signs, or contacts of GC underwent GC culture in addition to NAAT. When using AC2, all positive GC results were confirmed according to the manufacturer's instructions using the single analyte NAAT targeting a different RNA sequence: Aptima GC (Gen-Probe). All patients attending the clinic and undergoing GC screen- ing during a four-month period prior to, and following GC NAAT introduction were identified using laboratory databases; data were collected retrospectively. Follow-up attendances within an episode were excluded from analysis. Individuals diagnosed with GC were identified and case-notes were reviewed. We found that in the four months prior to the introduction of NAAT, 2307 symptomatic and asymptomatic patients were screened using GC culture alone, of which 20 (0.87%) were positive. Following the introduction of GC NAAT during a similar four-month period, a significant increase in screening was observed, with 3444 symptomatic and asymptomatic patients being screened with AC2. Of these, 43 (1.25%) were confirmed positive for GC. GC culture was also performed in 217 of the symptomatic individuals; of these 18 (8.3%) were culture posi- tive for GC. GC culture and NAAT showed concordance of positivity in 20/43 (46.5%) of cases. Eleven patients were NAAT positive, culture negative; 10/11 of these individuals had symptoms, signs or were high risk for GC. One of 11 cul- tured Neisseria meningitidis although subsequent GC NAAT testing using a different platform was also positive at the Sexually Transmitted Bacteria Reference Laboratory in Colindale, making it unlikely this was a false-positive. Twelve patients who were AC2 positive had no culture performed. Similarly to the findings by Killick et al., all patients with posi- tive GC cultures were also GC NAAT positive. In conclusion, following the introduction of GC NAAT we observed increased rates of screening and a doubling in the number of GC diagnoses during a similar time period. While it is possible there was an actual rise in the local GC incidence, the increase in diagnoses might also be attributable to a more sensitive test, acceptability of self-screening and a less time- consuming approach for the clinicians. The use of GC NAAT identified more infections than if culture alone had been used. Despite concern over the positive predictive value of GC NAAT in low prevalence settings, of those patients with posi- tive NAAT/negative cultures all had documented risk factors or symptoms of GC. We believe both these studies provide reassuring evidence for the use of GC NAAT in this setting, provided a confirmatory strategy is in place.

Towards better and safer blood transfusion

Although blood transfusion can be lifesaving, it involves risks such as transfusion-transmitted infections (TTIs). In late 2003 in Korea, 4 units of human immunodeficiency virus (HIV)-infected blood were transfused to recipients during the window period. At that time, it was also disclosed that many unqualified blood products had been supplied to hospitals [1]. These serious incidents prompted enactment of the National Blood Safety Improvement Projects by the government in 2004. In this issue of Blood Research, Kim et al. report a performance review of the 5-year project (2004-2009) to improve safety of blood supply provided by the Korea Red Cross (KRC) and other blood centers [2]. The project consists of 5 major categories: blood donor recruitment, blood testing and manufacturing, blood supply and use, enhancement of blood service expertise, and government responsibility for the national blood program. Our government has provided enormous financial support to implement this project. As a result, the number of blood collection centers has increased up to 127 nationwide, and blood-testing centers have been consolidated and upgraded. Furthermore, the Blood Information Sharing System (BISS) has been successfully established for networking between KRC and hospital blood centers; this system facilitates blood ordering and inquiry of donor eligibility. Nucleic acid amplification test (NAT) for HIV and hepatitis C virus (HCV) was started in 2005 and that for hepatitis B virus (HBV) was started in 2012. Between February 2005 and July 2006, 80 of 3,481,972 donors were found to be positive for HIV-1, as determined by NAT testing. Among the 80 donors, 4 were in antibody-negative window periods [3]. However, after implementation of NAT testing, no TTIs have been reported in Korea. Korea has made remarkable efforts to provide a safe blood supply for transfusion. Although Kim et al. have only briefly mentioned the major activities of the medical staff and physicians in hospitals as well as the role of the Korean Society of Blood Transfusion, continuous improvement in blood transfusion should be anticipated through cooperation among blood transfusion societies, blood centers, hospitals, and governments. Indeed, serious accidents have often prompted significant improvements in the field of transfusion medicine. However, I hope that there will be no more serious accidents in all the steps from blood donation to transfusion and that there is further progress towards better and safer blood transfusion.

Acute HIV-1 Infection in the Southeastern United States: A Cohort Study

In 1998 a collaboration between Duke University and the University of North Carolina, Chapel Hill (UNC) was founded to enhance identification of persons with acute HIV-1 infection (AHI). The Duke-UNC AHI Research Consortium Cohort consists of patients ≥18 years old with a positive nucleic acid amplification test (NAAT) and either a negative enzyme immunoassay (EIA) test or a positive EIA with a negative/indeterminate Western blot. Patients were referred to the cohort from acute care settings and state-funded HIV testing sites that use NAAT testing on pooled HIV-1 antibody-negative samples. Between 1998 and 2010, 155 patients with AHI were enrolled: 81 (52%) African-Americans, 63 (41%) white, non-Hispanics, 137 (88%) males, 108 (70%) men who have sex with men (MSM), and 18 (12%) females. The median age was 27 years (IQR 22-38). Most (n=138/155) reported symptoms with a median duration of 17.5 days. The median nadir CD4 count was 408 cells/mm(3) (IQR 289-563); the median observed peak HIV-1 level was 726,859 copies/ml (IQR 167,585-3,565,728). The emergency department was the most frequent site of initial presentation (n=55/152; 3 missing data). AHI diagnosis was made at time of first contact in 62/137 (45%; 18 missing data) patients. This prospectively enrolled cohort is the largest group of patients with AHI reported from the Southeastern United States. The demographics reflect the epidemic of this geographic area with a high proportion of African-Americans, including young black MSM. Highlighting the challenges of diagnosing AHI, less than half of the patients were diagnosed at the first healthcare visit. Women made up a small proportion despite increasing numbers in our clinics.

O3 Gonorrhoea test of cure: outcomes in a large urban sexual health service

BackgroundNew British Association for Sexual Health and HIV guidelines for the management of gonorrhoea in adults were introduced in June 2011. First line therapy was changed to ceftriaxone 500 mg...

P44 An evaluation of gonococcal testing using a roche cobas PCR platform in a low prevalence area

BackgroundThe countywide sexual health service have recently adopted the roche cobas dual PCR for gonorrhoea testing. The locality has a low prevalence of gonorrhoea compared to national rates.AimsTo assess the...

Can mailed swab samples be dry-shipped for the detection of Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis by nucleic acid amplification tests?

Dry-shipped and mailed vaginal swabs collected at home have been used in research studies for the detection of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (GC), and Trichomonas vaginalis (TV) by nucleic acid amplification tests (NAATs) in screening programs. A verification study was performed to compare the limit of detection of CT, GC, and TV on swabs that were dry-shipped to paired swabs that were wet-shipped in transport media through the US mail. The Centers for Disease Control and Prevention prepared inocula in sterile water to mock simulated urogenital swabs with high to low concentrations of CT and GC. Replicate swabs were inoculated with 100 μL of dilutions and were dry transported or placed into commercial transport media (“wet”) for mailing for NAAT testing. The University of Alabama prepared replicate concentrations of TV, which were similarly shipped and tested by NAAT. All paired dry and wet swabs were detectable for CT. For GC, all paired dry and wet swabs were detectable for GC at concentrations ≥103. At 102 and 10 CFU/mL, the 10 replicate GC results were variably positive. For TV, wet and dry shipped concentrations >102 TV/mL tested positive, while results at 10 TV/mL were negative for dry swabs. Holding replicate dry swabs at 55 ○C 5 days before testing did not affect results. NAATs were able to detect CT, GC, and TV on dry transported swabs. Using NAATs for testing home-collected, urogenital swabs mailed in a dry state to a laboratory may be useful for outreach screening programs.

HIV Screening via Fourth-Generation Immunoassay or Nucleic Acid Amplification Test in the United States: A Cost-Effectiveness Analysis

BackgroundAt least 10% of the 56,000 annual new HIV infections in the United States are caused by individuals with acute HIV infection (AHI). It unknown whether the health benefits and costs of routine nucleic acid amplification testing (NAAT) are justified, given the availability of newer fourth-generation immunoassay tests.MethodsUsing a dynamic HIV transmission model instantiated with U.S. epidemiologic, demographic, and behavioral data, I estimated the number of acute infections identified, HIV infections prevented, quality-adjusted life years (QALYs) gained, and the cost-effectiveness of alternative screening strategies. I varied the target population (everyone aged 15-64, injection drug users [IDUs] and men who have sex with men [MSM], or MSM only), screening frequency (annually, or every six months), and test(s) utilized (fourth-generation immunoassay only, or immunoassay followed by pooled NAAT).ResultsAnnual immunoassay testing of MSM reduces incidence by 9.5% and costs <$10,000 per QALY gained. Adding pooled NAAT identifies 410 AHI per year, prevents 9.6% of new cases, costs $92,000 per QALY gained, and remains <$100,000 per QALY gained in settings where undiagnosed HIV prevalence exceeds 4%. Screening IDUs and MSM annually with fourth-generation immunoassay reduces incidence by 13% with cost-effectiveness <$10,000 per QALY gained. Increasing the screening frequency to every six months reduces incidence by 11% (MSM only) or 16% (MSM and IDUs) and costs <$20,000 per QALY gained.ConclusionsPooled NAAT testing every 12 months of MSM and IDUs in the United States prevents a modest number of infections, but may be cost-effective given sufficiently high HIV prevalence levels. However, testing via fourth-generation immunoassay every six months prevents a greater number of infections, is more economically efficient, and may obviate the benefits of acute HIV screening via NAAT.

Testing Men Who Have Sex With Men for Urethral Infection With Chlamydia trachomatis and Neisseria gonorrhoeae Is Only Half the Job, and We Need the Right Tools

Standard operating procedure in STD clinics commonly has been to test urethral specimens when evaluating males, whether they are heterosexual or men who have sex with men (MSM). Rectal or oropharyngeal specimens may be tested in MSM with symptoms, or in some clinics as screening tests if individuals report sexual practices that would indicate risk of infection at these sites. In a report in this issue of Sexually Transmitted Diseases, Marcus and colleagues studied the prevalence of infection with Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) in the urethra, the oropharynx, and rectum in asymptomatic MSM visiting the San Francisco STD clinic.1 A retrospective analysis of 3398 patient visits found CT or GC at 549 (16.2%) of those visits. The prevalence of infections among these asymptomatic men ranged from a high of 7.8% for rectal CT to a low of 0.4% for urethral GC. Strikingly, 83.8% of CT and GC infections would have been missed if only urethral screening was performed. What was found in the Marcus study, and in others, as well, is that the majority of infections with CT/GC in MSM are not in the urethra. The first major study to make this point was performed by Kent and colleagues, in 2 clinics in San Francisco, where they found that 50% of chlamydial and gonococcal infections were extraurethral.2 That finding has been confirmed by a number of approaches, including retrospective chart reviews and prospectively designed studies (Table 1). While these studies have focused on rectal and pharyngeal CT/GC infections in MSM, it must be noted that such infections are far from rare in women.12,13 In many clinical settings, the infections in women will be seen more often than those in men. These extragenital infections should not be ignored now, and we need more research to better define their potential consequences. Both CT and GC are recognized as causes of proctitis, and even asymptomatic infections have been associated with HIV transmission. 14 Current CDC recommendations call for routine screening of the oropharynx and rectum in MSM who may be exposed to GC or CT at those sites. It is not clear whether pharyngeal infections have a major direct impact on health. But evidence is emerging that infection can be transmitted from the oropharynx to the urethra of sex partners, thus continuing chains of infection.15 All of the cited studies have been made possible by the introduction and application of highly sensitive and specific nucleic acid amplification tests (NAATs) for the diagnosis of CT and GC infections. NAATs are recommended for routine diagnosis of CT/GC infections.15 Where direct comparisons have been done, it has been shown that the increment in sensitivity for NAATs as compared to culture is greater with pharyngeal and rectal specimens than it is with cervical and urethral specimens. An approximate doubling of the number of infections detected has been obtained with NAATs. 4,11 Alas, there remains a gap wherein the best tests are not readily available to the patients and providers who need them. Several NAATs are commercially available and have received FDA clearance for male and female urine specimens, urethral swabs from men, and cervical and vaginal swabs from women. Unfortunately, none have been cleared by the FDA for pharyngeal or rectal specimens. But the CDC, recognizing the superior performance of these tests used on these specimens, has taken an unusual step and recommended the use of NAATs for diagnosis of CT/GC in oropharyngeal and rectal specimens, even though such use has not received FDA clearance. 16 The

Gonorrhea infection in women: prevalence, effects, screening, and management

Gonorrhea is a set of clinical conditions resulting from infection with the sexually-acquired bacterial pathogen Neisseria gonorrhoeae. Acquisition may involve multiple mucosal sites in the lower female genital tract, including the urethra, cervix, Bartholin’s and Skene’s glands, as well as the anorectal canal, pharynx, and conjunctivae. It may spread to the upper genital tract, uterine tubes, abdominal cavity, and other systemic sites. Gonorrhea is the second most commonly reported sexually-transmitted infection in the US and rates are higher among women than men. Women and infants are affected disproportionately by gonorrhea, because early infection may be asymptomatic and also because extension of infection is often associated with serious sequelae. Screening is critical for infection identification and the prevention or limitation of upper genital tract spread, and horizontal and vertical transmission. Routine genital screening is recommended annually for all sexually active women at risk for infection, including women aged < 25 years and older women with one or more of the following risks: a previous gonorrhea infection, the presence of other sexually transmitted diseases, new or multiple sex partners, inconsistent condom use, commercial sex work, drug use, or human immunodeficiency virus infection with sexual activity or pregnancy. Pharyngeal gonococcal infections are common in adolescents, and direct culture screening is necessary to identify affected individuals. Nucleic acid amplification tests (NAATs) are considered the standard for screening and diagnosis. Although urine NAAT testing is most commonly used, there is growing support for vaginal swabs collected by providers or patients themselves. Resistance to all antibiotics currently recommended for the treatment of gonorrhea has been documented and complicates therapeutic strategies. The Centers for Disease Control and Prevention recommend treatment of gonorrhea with a single class of drugs, ie, the cephalosporins.

Laboratory Techniques for Human Viral Encephalitis Diagnosis

Encephalitis is an inflammatory process involving the parenchyma of the brain. It typically presents as a clinical syndrome characterised by fever, headache and altered conscious level, often with focal neurological deficits and fits. The clinical presentation overlaps with other diseases of the central nervous system including viral and bacterial meningitis, and brain abscess. The causes of encephalitis are legion, and include principally viral but also bacterial, parasitic and fungal pathogens. Noninfectious aetiologies, especially autoimmune conditions such as potassium channel voltage gated antibodies and anti-NDMA receptor antibodies, are increasingly recognised. Diagnosis comes from clinical examination, neuroimaging and laboratory testing. With such a wide range of potential pathogens a syndromic approach to diagnosis is preferred, testing for a range of organisms. Traditional techniques such as cell culture and direct virus antigen detection have little or no role nowadays. Laboratory diagnosis of viral encephalitis is ideally based on examination of cerebrospinal fluid (CSF) for cells, protein and glucose, followed by nucleic acid amplification tests (NAAT) such as polymerase chain reaction (PCR) for a range of viral targets. Samples other than CSF sometimes give a definitive or probable aetiological diagnosis; examples include skin biopsy in rabies, and serum NAAT and antibody tests for some arboviruses and enteroviruses. Newer approaches to amplification and to multitarget detection are becoming increasingly important. Detection of intrathecal antibody production against specific viruses retains a place in diagnosis where NAAT is negative. Some of the laboratory techniques available will be discussed in this article.

Induced Macrolide Resistance in Mycoplasma genitalium Isolates from Patients with Recurrent Nongonococcal Urethritis

Mycoplasma genitalium accounts for as much as 15 to 20% of cases of male nongonococcal urethritis (NGU) (7). It is also implicated in female cervicitis and increasingly so in pelvic inflammatory disease (3). Since it is a fastidious microorganism that is very difficult to culture, nucleic acid amplification tests (NAAT) have become invaluable in its detection and microbiological evaluation. Currently recommended treatments of NGU include multidoses of doxycycline (100 mg twice daily for 7 days) or a single dose of azithromycin (1 g). With regard to M. genitalium-positive NGU, a recent randomized study has shown multidose treatment with doxycycline to be inferior to single-dose azithromycin (cure rates of 45% versus 87%, respectively) (8). However, even single-dose azithromycin can be associated with treatment failure rates of up to 28% (2). An extended 5-day course of azithromycin (500 mg on day 1, followed by 250 mg on days 2 to 5) has a much higher cure rate of up to 96% (1) but becomes less efficacious when used after initial treatment failure with single-dose azithromycin (6). Jensen et al. (4) have shown that macrolide resistance in M. genitalium can be induced by insufficient therapy with single-dose azithromycin and found the resistance to be strongly associated with three single-base mutations (A2058C, A2058G, A2059G) in region V of the 23S rRNA gene (4). They developed a conventional PCR to detect all of these mutations. In September 2009, we started M. genitalium NAAT testing of genital samples from selected patients with recurrent NGU at the Christchurch Sexual Health Centre, Christchurch, New Zealand. The PCR was performed as described by Jensen et al. (5) with the 2× Universal TaqMan gene expression master mix (Applied Biosystems, Life Technologies, Foster City, CA). Between September 2009 and October 2010, 52 samples were collected and M. genitalium was detected in 11 (21%) samples. The nucleic acid extracts were stored at −80°C until October 2010, when we retrospectively performed PCR and DNA sequencing on these extracts to look for the single-base mutations mentioned above, using the method described by Jensen et al. (4). Of the 11 nucleic acid extracts, we were able to amplify and sequence the 23S rRNA genes of 9 extracts. PCR of the other 2 nucleic acid extracts did not yield an amplicon upon repeat testing, probably due to nucleic acid degradation during storage. Of the 9 sequenced nucleic acid extracts, 4 extracts contained the A2059G mutation, whereas none contained mutations at position 2058. We retrospectively reviewed the notes for the relevant patients (those with extracts containing the mutation) and found that all four patients had previously been treated multiple times for sexually transmitted infections. We were able to determine that three of these patients had received single-dose azithromycin between 34 and 58 days preceding the positive test for M. genitalium; the fourth patient had also received single-dose azithromycin in the few weeks preceding a positive test, but we were unable to determine the exact time frame. All four patients had received an extended course of azithromycin following the diagnosis of M. genitalium urethritis: two experienced treatment failure, whereas the other two were subsequently cured, based on the fact that M. genitalium DNA was no longer detectable. Of the 5 patients whose M. genitalium extracts did not contain any of the macrolide resistance mutations (of the 9 extracts whose rRNA genes we were able to amplify and sequence), 3 had experienced successful empirical therapy with single-dose azithromycin (2 patients) or extended-dose azithromycin (1 patient); 1 patient was lost to follow up. The remaining 1 patient had received treatment with single-dose azithromycin, but upon subsequent testing, M. genitalium DNA was detectable and in this case contained the A2059G mutation, and the patient was included in our group above. This nicely demonstrates the induction of macrolide resistance by single-dose azithromycin treatment. To our knowledge, this is the first report from New Zealand describing macrolide resistance in M. genitalium. Despite a very limited number of samples, we have evidence that the A2059G mutation conferring induced macrolide resistance is present at a high frequency in M. genitalium extracts from patients with recurrent NGU at the Christchurch Sexual Health Centre. This brings into question whether or not single-dose azithromycin should be the first-line treatment of choice for M. genitalium-positive urethritis. At the Christchurch Sexual Health Centre, the current practice is to prescribe an extended course of azithromycin for all cases of M. genitalium-positive urethritis (primarily because moxifloxacin is currently not readily accessible in New Zealand). We also note with interest that in two patients with the resistant isolate, infection was still cleared with an extended course of azithromycin. This would suggest that macrolide resistance conferred by the A2059G mutation was not absolute. Clearly, the subject of macrolide resistance in M. genitalium requires more study.

Gonococcal NAATs: what is the current state of play in England and Wales?

The aim of this study was to determine how widespread the use is of dual nucleic acid amplification tests (NAATs) for the diagnosis of both Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) in England and Wales. A structured telephone questionnaire was used to collect information on the method of dual testing used by laboratories, the patient groups tested, the types of specimens obtained and the use of GC culture. Of the 108 laboratories participating, 29% performed dual CT and GC NAAT assays. The platforms used included: (i) BD Probetec (19/31), (ii) Aptima Combo 2 (9/31) and (iii) COBAS AMPLICOR (2/31). GC-positive specimens were either repeated using the same test (21) or an alternative target (9). Most laboratories confirmed positive GC NAATs by performing culture (26/31). Laboratories performed dual NAAT testing on specimens sourced from both community and genitourinary medicine clinic settings, and on a wide variety of different specimen types. This survey highlights a lack of consistency in the current use of dual NAAT platforms in the UK and the need for national guidelines.

Prisoners as Organ Donors: Is It Worth the Effort? Is It Ethical?

Prisoners have generally been excluded from donation because of ethical and infectious disease concerns. We propose a plan, which would address both concerns and examine the potential impact. Interested inmates would approach the prison's medical team expressing interest in living donation (LD). Principle steps in the process are (1) consent to evaluation and a two-step surgical consent. (2) Nucleic acid amplification testing (NAAT). A standard LD workup would be initiated. If the results were acceptable, the inmate would sign the first surgical consent. NAAT for human immunodeficiency virus (HIV) and hepatits B and C virus would be performed 3 weeks apart. Assuming acceptable results, prisoner and family would sign the second consent, and the inmate would be scheduled for LD surgery. The inmate would be in medical isolation until the time of donation. NAAT testing has enabled the window period to be small enough to allow close observation and monitoring of the prisoner, enabling safe donation. The paternalistic protection of prisoners would ensure that experiments were not performed. This plan would allow prisoners the ability to participate in opportunities provided noninmate people. There are currently 2.2 million inmates; the incidence of HIV is 1.8%, decreasing the potential pool to 2.1 million. A donation rate of 1% could provide 21,000 kidneys. Advances in medical technology and the acknowledgment that prisoners can consent to complex but standard medical procedures have opened up a potential pool of organ donors that could dramatically impact the organ shortage.

Neisseria gonorrhoeae infection in urban Sydney women: prevalence and predictors

The notification rate of female gonorrhoea in urban Sydney is very low. With the increasing use of nucleic acid amplification tests (NAAT), demonstrating a low prevalence of gonorrhoea in women would have important implications for the reliability of positive results. We determined the prevalence of female cervical gonorrhoea in our urban sexual health clinic and identified associated clinical, behavioural and demographic variables that may allow more targeted screening practices. The Sydney Sexual Health Centre database was used to identify women tested for cervical gonorrhoea between 1997 and 2007. Diagnostic, demographic and behavioural information were extracted to ascertain the prevalence of gonorrhoea and describe variables associated with infection. Additionally, a case control study was conducted of cervical gonorrhoea cases from January 2000 to December 2005, with two gonorrhoea negative women selected for each case as controls. A blinded researcher examined each medical record to determine genital symptoms, being a contact of gonorrhoea, sex work, sex outside of Australia, injecting drug use. Between 1997 and 2007, 77 women were diagnosed with cervical gonorrhoea, a prevalence of 0.37%. Results of the case control study reveal that women with gonorrhoea were more likely to be symptomatic [odds ratio (OR) 3.7, 95% confidence interval (CI) 1.7-8.4], be a known contact of gonorrhoea (OR 264, 95% CI 149-470), or have had recent sex overseas, or with a partner from overseas (OR 1.75, 95% CI 1.11-2.75). Cervical gonorrhoea infection is rare in our urban sexual health clinic, and even more unlikely in asymptomatic women without risk factors. This low prevalence of gonorrhoea, particularly in asymptomatic women, decreases the reliability of positive NAAT test results. This has important implications for the screening of asymptomatic women presenting to urban sexual health clinics in Australia.

Regarding unexpected severe and life-threatening donor-transmitted viral infections and use of high-risk behavior donors

Regarding unexpected severe and life-threatening donor-transmitted viral infections and use of high-risk behavior donors

Reports on the Prevalence of Clinical Conditions Are More Convincing When Supported by Objective Evidence

Reports on the Prevalence of Clinical Conditions Are More Convincing When Supported by Objective Evidence

Internet-Based Screening for Chlamydia trachomatis to Reach Nonclinic Populations With Mailed Self-Administered Vaginal Swabs

Testing for Chlamydia trachomatis by nucleic acid amplification tests (NAATs) using self-collected vaginal swabs (VS) is acceptable and accurate. The objectives were to implement an educational Internet-based program for women to facilitate home screening, to determine whether women would request and use self-collected VS kits, to determine associated risk factors for infection, and to determine satisfaction with the process. The website, www.iwantthekit.org, was designed to encourage women > or =14 years to obtain home-sampling kits. Kits could be obtained in the community, requested by Internet/e-mail, or telephone. Users mailed the self-collected VS to the laboratory. Swabs were tested by 3 NAAT assays. Respondents called for results. Forty-one of 400 (10.3%) women were chlamydia positive; 95.1% were treated. Questionnaires indicated 89.5% preferred self-collection, 93.5% rated collection easy/very easy, and 86.3% would use the Internet program again. Black race and age <25 years were associated independently with being chlamydia positive, while use of birth control and non-consensual sex were protective. Thirty-six of 41 (87.8%) positive samples were positive by all 3 NAATs, 5/41 (12.2%) were positive by only 2 NAATs, and none were positive by only 1 NAAT. The Internet/e-mail request method was better than the community pick-up approach because 97.2% of kit requests were e-mailed and 87.5% of kits returned for testing were e-mail requested. Women will use the Internet to request and use home-sampling kits for chlamydia. NAAT testing performed well on dry-transported VS. High prevalence was detected and questionnaires indicated high-risk sexual behavior.

Hepatitis B virus blood screening: unfinished agendas

The risk of transfusion-transmitted hepatitis B virus (TTHBV) has been steadily reduced through the use of volunteer donors, enhanced donor questioning, and increasingly sensitive hepatitis B surface antigen (HBsAg) tests. In a few countries, screening by antibody to hepatitis B core antigen (anti-HBc) and/or hepatitis B virus (HBV) nucleic acid amplification tests (NAT) has also been introduced. Nevertheless, the risk of TTHBV in most countries is higher than the risk of either human immunodeficiency virus-1 (HIV-1) or hepatitis C virus (HCV). HBV screening practices vary both in terms of the markers screened and the tests employed, and are often dependent on a country's healthcare resources. Anti-HBc screening could be employed as an additional safety feature in HBV low-prevalence countries, but would lead to the rejection of a high percentage of otherwise acceptable donations in HBV moderate- and high-prevalence countries. It has been argued that only individual-donor HBV NAT testing would substantially reduce the risk of TTHBV beyond that achieved by the most sensitive HBsAg tests. However, studies from countries with low, moderate and high HBV prevalence have demonstrated NAT yield from window period- and late stage HBV-infected donors, even using minipool testing following the most sensitive HBsAg tests.

Epidemiology of blood donors in Japan, positive for hepatitis B virus and hepatitis C virus by nucleic acid amplification testing

The Japanese Red Cross screens seronegative blood donors by nucleic acid amplification testing (NAT) for hepatitis B, hepatitis C and human immunodeficiency virus-1 markers. NAT-positive donors thus identified seemed to have a different infectious background from serologically positive donors. The purpose of our study was to characterize this background in the hepatitis B virus (HBV) and hepatitis C virus (HCV) NAT-positive donors. Some 328 HBV DNA-positive and 44 HCV RNA-positive donors were detected by NAT testing of seronegative blood donors. These were characterized regarding age, gender and genotype of HBV and HCV. Those who were HBV NAT-positive were mainly young, in particular teenage girls. In Japan, genotypes C and B have previously been dominant, but recently genotype A has increased, and genotype H was recently detected. In HBV NAT-positive donors, the rate of genotype A was high (12.2%) compared with patients in hospital (1.7-2%). Donors who were HCV NAT-positive were also young, but mostly men in their twenties. The ratio of genotype 1b to 2a or 1b to 2b in HCV NAT-positive donors differed from that of hospitalized patients in Japan. We did not find genotype 1a, which is dominant in the USA. The high-risk donors detected by NAT were mainly young, with a different distribution of genotypes from that of hospitalized patients, regarding both HBV and HCV. The rare HBV genotype H has been found for the first time in Japan. The findings reflect the present spread of hepatitis viruses B and C.

Should HBV DNA NAT replace HBsAg and/or anti-HBc screening of blood donors?

Prevention of transfusion-transmitted hepatitis B virus (HBV) has historically relied on serological screening of blood donors using progressively more sensitive HBsAg assays; in some countries anti-HBc assays have also been employed to detect chronic carriers with low-level viremia who lack detectable HBsAg. Nucleic acid amplification testing (NAT) for HCV and HIV has been successfully introduced to screen donors in many developed countries over the past several years; for logistical and cost reasons HCV/HIV NAT screening has been applied to mini-pools (MP) of eight to 96 donor specimens, with only minimal impact of MP dilutions on clinical sensitivity for interdiction of window period (WP) donations. In several countries (e.g., Japan and Germany), HBV NAT has been added to HIV/HCV MP-NAT blood donor screening with small incremental yields of HBsAg/anti-HBc-negative donations, and the major vendors of NAT systems (Roche and Chiron/Gen-Probe) have been developing triplex assays that include HBV DNA detection capacity without compromising HIV or HCV detection. Pooled specimen HBV NAT has also become the standard of practice for screening source plasma donors, with pressure to include HBV DNA detection as a required procedure for use of recovered plasma in manufacture of fractionated derivatives. However, there is controversy over the magnitude of the incremental yield and clinical benefit of HBV MP-NAT over serological screening strategies, as well as the impact of implementation of HBV NAT on need for retention of HBsAg and anti-HBc screening. This presentation will review recent modeled and empirical data on the value of HBV MP- and individual donation (ID)-NAT for detection of (1) pre-HBsAg WP units and (2) chronic anti-HBc-reactive carriers with undetectable HBsAg. The presentation will also review policy considerations and data that address the potential for discontinuation of either HBsAg or anti-HBc following implementation of HBV NAT. Finally it will address the cost effectiveness of incorporation of HBV DNA detection into HBV screening and NAT testing algorithms.