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An enzyme-linked immunosorbent assay (ELISA) has been developed that can detect autoantibodies against ribosomal P proteins in patients with system lupus erythematosus (SLE). The assay uses a synthetic version of a 22-amino acid sequence common to all three P proteins.

An enzyme-linked immunoassy called ELISPOT appears capable of decting individual immune cells that are producing HIV. HIV infects immune cells called CD4+ T cells, monocytes and macrophages and then uses the cell to produce more HIV. Researchers used ELISPOT to measure HIV-producing cells in blood samples and a human T-lymphoblastoid cell line that were infected with HIV. The assay showed that 11% to 24% of the blood cells and 5% to 9% of the cells in the cell line were producing HIV.

Background: Upper genital tract chlamydial infections in women are on the increase, and serology might be a convenient tool for diagnosis. Evaluations of this approach are needed in women with or without microbiologic evidence of organisms in the upper genital tract. Goals: To compare the results of antibody assays with cervical culture and upper genital tract histopathology in women with pelvic pain and chlamydial plasmid DNA in endometrial biopsies. Study Design: Chlamydia trachomatis plasmid DNA was detected by polymerase chain reaction (PCR) on extracted deparaffinized endometrial biopsy tissue. Five antichlamydial antibody assays were performed measuring total antibodies or immunoglobulin G (IgG), IgM, and IgA classes on sera from 14 women with plasmid DNA as well as 31 without plasmid DNA. Results: Accepting the presence of plasmid DNA as the gold standard, no single test had total diagnostic accuracy. The best sensitivity and specificity occurred with the following assays: whole inclusion fluorescence (WIF) (100% and 80.6%); microimmunofluorescence IgM (MIF IgM) (78.6% and 93.6%); and heatshock protein-60 enzyme immunoassay (42.9% and 100%). Although recombinant anti-lipopolysaccharide enzyme-linked immunosorbent assays measured antichlamydial antibodies in a large proportion of these women, specificity was low. The sensitivity and specificity of cervical culture was 28.6% and 100% and of endometrial histopathology was 71.4% and 48.4%. Analysis of patient serological profiles suggested that 6 women without plasmid DNA may have been cases that were missed by PCR. Conclusions: Evaluations of assays to diagnosis Chlamydia trachomatis upper genital tract infections could use the presence of organisms or their markers in the upper genital tract as a standard of comparison. Some of these serological assays, such as WIF or MIF IgM, may be helpful in diagnosis, but more studies are needed., No single blood test appears to be able to accurately distinguish women with and without chlamydia infections who have characteristic pelvic pain. Blood tests were performed on 45 symptomatic women and compared with genetic tests on tissue samples. Fourteen of these women had confirmed chlamydia infections and 31 were not infected. The percentage of true positive blood test results ranged from 42.9% using the heatshock protein-60 enzyme immunoassay (HSP-60 EIA) to 100% using whole inclusion fluorescence (WIF). The percentage of true negative blood test results ranged from 80.6% using WIF to 100% using HSP-60 EIA.

Abstract Objectives: To estimate the prevalence of Chlamydia trachomatis in asymptomatic women attending general practice; to assess the potential of the ligase chain reaction as a screening tool; and to [...]

Background and Objectives: The Syva MicroTrak enzyme immunoassay (EIA) is used widely for screening women infected with Chlamydia trachomatis. Confirmatory tests used in conjunction with EIA screening have shown that false-positive results are common. Goals: To evaluate the specificity of the Syva MicroTrak EIA by confirmation of positive specimens with the Syva Direct Fluorescent Specimen Test. Study Design: Of 6,039 endocervical specimens collected from women attending Colorado family planning clinics, 328 positive EIA results (5.4%) were obtained by Syva MicroTrak EIA. A random subset of 136 positive specimens was tested by Syva Direct Specimen Test. Twenty of 136 specimens (14.7%) negative by Syva Direct Specimen testing were also tested by Syva blocking antibody tests (9 of 20 positive, 45%) and Roche Amplicor polymerase chain reaction (PCR; 6 of 20 positive, 30%). Of 20 specimens positive by Syva MicroTrak EIA and negative by Syva Direct Specimen Test, 11 (55%) were also negative by blocking antibody and PCR, including three specimens with initial EIA sample-to-cutoff ratios greater than 2. Conclusions: Confirmatory testing of Syva MicroTrak EIA positive specimens with Syva Direct Specimen Test showed that 14.7% were false positive. Coupling the Syva Direct Specimen test with either blocking antibody or PCR reduces the rate of false-positive results to 8%., A popular commercial screening test for Chlamydia appears to require follow-up testing on women testing positive to reduce the number of false-positive tests, but any one follow-up test may produce a false-negative result. Among 136 cervical secretion specimens originally testing positive for Chlamydia, 20, or 15%, tested negative on a second type of test. Of these 20, 11 tested negative on both of yet two other types of test while the rest tested positive on one or both of these other tests. Therefore, follow-up testing by two different tests reduced the false-positive rate from 15% to 8%.

Background: The clinical diagnosis of primary and secondary syphilis can be difficult because of the wide variability of lesions. The available laboratory tests (dark-field microscopy and direct fluorescent antibody) require specialized microscopes and skilled technicians, and serologic tests are insensitive in early infection. Methods: Dark-field microscopy and monoclonal antibody staining were compared to a new solid-phase enzyme-linked immunosorbent assay (Visuwell test) for detection of T pallidum in lesion exudate of 188 patients with genital lesions. Results: Sixty-four patients (34%) had lesions of early syphilis diagnosed by either dark-field, monoclonal antibody staining, or both. The Visuwell test and dark-field examination were positive in 52 (813%) and 55 (85.9%) of the 64 patients, respectively, whereas the monoclonal antibody staining technique demonstrated the presence of T pallidum in 59 (92.2%) of the 64 patients. The Visuwell test gave a negative result in 111 of 124 patients who had negative dark-field and direct fluorescent antibody test results (89.5% specificity). Conclusions: The Visuwell test is an alternative method for evaluating genital ulcers but is less sensitive and specific than existing tests., A new test to detect early syphilis that does not depend on laboratory use may not be as accurate as laboratory tests. Researchers compared a new solid-phase enzyme-lined immunosorbent assay, or Visuwell test, to the standard dark-field microscopy test and to monoclonal antibody testing in analyzing genital lesions for Treponema pallidum, the organism that causes syphilis. The monoclonal antibody test and dark-field microscopy were more accurate than the Visuwell test. Specimen collection was simpler for the Visuwell and monoclonal antibody tests than for dark-field microscopy. The Visuwell test provides quicker results, although not necessarily accurate.

Background: The CYFRA 21-1, a newly developed sandwich enzyme-linked immunosorbent assay (ELISA), was used to measure soluble cytokeratin 19 fragment in serum that is expressed in simple epithelium and its [...]

Background and Goal: The VIDAS Enzyme Linked Fluorescent Assay is a fully automated assay for the detection of Chlamydia trachomatis in clinical specimens. Because there is an increasing demand for automated assays for large volume laboratories and there is little performance data available, the authors evaluated the performance of the VIDAS enzyme linked fluorescent assay by comparing it with Chlamydiazyme and polymerase chain reaction. Study Design: Endocervical swabs from 330 women attending a hospital based obstetrics/gynecology clinic and 100 first void urine specimens from males attending a sexually transmitted disease clinic were tested by enzyme linked fluorescent assay, Chlamydiazyme, and polymerase chain reaction. Results: Fourteen of 330 endocervical specimens and 14 of 100 first void urine specimens were positive by Chlamydiazyme. Enzyme linked fluorescent assay detected 12 of 14 endocervical and 11 of 14 first void urine specimens. Compared with Chlamydiazyme, enzyme linked fluorescent assay had a sensitivity of 85.7% (12 of 14) for endocervical swabs and 76.9% (11 of 14) for first void urine specimens. Polymerase chain reaction detected an additional rive endocervical and two first void urine specimens that had negative results by both enzyme linked fluorescent assay and Chlamydiazyme. All 7 were confirmed positive by polymerase chain reaction using a second primer set. Using an expanded gold standard of blocked Chiamydiazyme and confirmed polymerase chain reaction, enzyme linked fluorescent assay had a sensitivity of 63.2% (12 of 19) for endocervical swabs and 68.8% (11 of 16) for first void urine specimens compared with 73.7% (14 of 19) and 87.5% (14 of 16) for Chlamydiazyme. Polymerase chain reaction had a sensitivity of 100% (19 of 19) and 93.8% (15 of 16) for endocervical swabs and first void urine specimens, respectively. The specificity of enzyme linked fluorescent assay and Chiamydiazyme was 100%. Conclusions: The VIDAS enzyme linked fluorescent assay for the detection of Chlamydia trachomatis in genitourinary specimens is highly specific but is not sufficiently sensitive for use as a routine diagnostic test., The VIDAS enzyme linked fluorescent assay (ELFA) may not be accurate enough to use as a routine diagnostic test for Chlamydia trachomatis in cervical and urine cultures. Researchers compared the results of the VIDAS test to those of Chlamydiazyme and polymerase chain reaction tests using specimens from 330 female and 100 male patients. The VIDAS ELFA had a sensitivity of 63.2% with the female cervical specimens, and a sensitivity of 68.8% with the male urine specimens. The VIDAS ELFA was less sensitive than Chlamydiazyme, as judged against polymerase chain reaction results. VIDAS ELFA did not produce any false positive results. Most of the female patients did not have symptoms of chlamydia, while some of the men did.

Two antibody tests, latex fixation and enzyme linked immunosorbent assay (ELISA) for IgM, seem to be equally accurate and seem to be more accurate than the ELISA for IgA or IgG. These tests screen patients for rheumatoid arthritis (RA) by detecting the presence of antibodies associated with RA. Researchers compared the accuracy and predictability of disease progression using these tests on 1,988 patients with suspected RA. The ELISAs for IgM, IgG, and IgA correctly identified patients with RA 69%, 72%, and 44% of the time, respectively, and correctly identified patients without RA 86%, 84%, and 52% of the time, respectively. The latex fixation test correctly identified patients with RA 65.6% of the time and patients without RA 90.9% of the time. The latex fixation test gave the most accurate prediction rate for advancing disease (83.3%). The ELISA test for IgM was more accurate in younger patients and in men.

HIV tests of intravenous drug users based on detection of antibody to the virus generally appear to agree with tests based on detection of viral DNA. Antibody-based tests may be falsely negative if a person has recently been infected and is not producing antibodies. Researchers performed antibody tests and viral DNA tests on 337 injection drug users. Three of the 286 participants with negative antibody tests had positive viral DNA tests. These three people with false-negative antibody tests had engaged in high risk sexual or drug-use behavior in the six months preceding their tests. One of the 49 participants who had a positive antibody test had a negative DNA test. The tests agree with one another in 331 (98.8%) of 335 cases. The commonly used antibody test, which is less expensive and more standardized than the DNA test, appears to be adequate, though it may fail to detect cases of recent infection.

Four anti-HIV-1/HIV-2 enzyme immunoassays (EIAs) appear to be similarly effective in diagnosing HIV infection in the Australian population. Four different EIAs were evaluated at 12 Australian Public Health Laboratories and seven Australian Red Cross Blood Transfusion centers. The four tests were manufactured by Organon Teknika, Abbott, Diagnostics Pasteur and Genetic Systems. The specificity of the tests, or the ability of the test to correctly indicate that HIV infection is present and not to indicate it as present when it is not, were similar. The Organon Teknika test had a specificity of 99.85%; the Abbott test a specificity of 99.92%; the Diagnostics Pasteur test a specificity of 99.46%; and the Genetic Systems test a specificity of 99.67%. Sensitivity, or the likelihood that the disease is present when the test is positive, was highest for the Abbott test.

Background and Objectives: The aim of the study was to investigate the value of the Gen-Probe PACE 2 assay for routine diagnosis of Chlamydia trachomatis in genital specimens of symptomatic and asymptomatic men and women patients. Study Design: Samples were collected from 90 men and 299 women patients and tested by using the Gen-Probe assay and the EIA MicroTrak. Discrepant results were further analyzed by immunofluorescence, a second run of the Gen-Probe assay, and a probe competition assay (PCA) to establish the number of true positive and negative outcomes based on the two tests used. Results: The overall prevalence of C. trachomatis was 8.5% in all patients tested (women: 3.7%, men: 13.3%) with an overall agreement of 95.4% between the two diagnostic methods. Of the 18 discordant results, 12 (67%) were considered to be false positive in the Gen-Probe assay and 3 (16%) false positive in the EIA. Two (11%) positive results were missed in the Gen-Probe assay and 1 (6%) in the EIA, all observed in female specimens. The sensitivities and specificities of the EIA were 91.7% and 100% for men and 100% and 99% for women, and for the Gen-Probe assay were 83.3% and 100% for men and 100% and 95.8% for women, respectively, when compared with true positive and true negative results. Although the predictive value for all positive results (PVP) was 88% for the EIA and 78.2% for the Gen-Probe assay, it was only 47.8% for positive female samples when using the Gen-Probe assay. Conclusion: The Gen-Probe assay revealed a sensitivity comparable with the EIA. The accuracy of test results provided by a single Gen-Probe assay was considerably lower than by MicroTrak reducing the utility of PACE 2 as a diagnostic technique for Chlamydia diagnosis. Due to the high rate of false-positive samples in the Gen-Probe assay, positive results with a low value of relative light units have to be further analyzed by confirmation procedures., Gen-Probe's PACE 2 test for Chlamydia trachomatis (C. trachomatis) infection appears to have a high false positive rate compared to the MicroTrak enzyme immunoassay (EIA). PACE 2 analyzes DNA sequences in order to diagnose infections with C. trachomatis. Chlamydial infections may be sexually transmitted. People infected with C. trachomatis may or may not have symptoms. Samples were collected from 90 men and 299 women. The samples were tested by PACE 2 and MicroTrak EIA. Agreement in results between the two tests occurred in 95.3% of the cases. When results differed between the two tests they were analyzed further. Fifteen of eighteen samples with differing results were from women. Twelve (67%) of these false-positive results occurred with PACE 2 and three (16%) occurred with MicroTrak. PACE 2 did not identify chlamydial infection in two male samples and MicroTrak did not identify one infection in a male sample. Because of the high false positive rate with PACE 2, borderline samples require further analysis.

Background and Objectives: Non-invasive tests are needed to detect Chlamydia trachomatis in the genital tract. For men, urine appears to be a useful specimen for chlamydial antigen or nucleic acid detection. Goal of this Study: To evaluate enzyme immunoassays (EIA) for chlamydial antigens in first catch urine (FCU) from symptomatic and asymptomatic men. Study Design: We conducted five different studies; FCUs and urethral swabs were collected from 1,341 symptomatic and 816 asymptomatic males. Four EIAs (SureCell, Chlamydiazyme, MicroTrak and IDEIA) were tested on the FCU sediments. Results: Prevalence of chlamydia by tissue culture isolation was 6% for asymptomatic and 14% for symptomatic men. With symptomatic males, the EIA sensitivities and specificities were: SureCell 85% and 97%, IDEIA 82% and 98%, MicroTrak 86% and 99%, and Chlamydiazyme 91% and 95%. For asymptomatic men, Chlamydiazyme sensitivity was 35% with frozen urine vs 77% with fresh urine. Overall, tissue culture sensitivity was about 90%. Conclusion: EIA results on FCU sediments are comparable to that of tissue culture isolation on urethral swabs. In many settings, FCU may be the specimen of choice for diagnosing chlamydial infections in men., Testing first catch urine samples with enzyme immunoassays (EIAs) appears to provide a relatively effective, non-invasive test for chlamydial infections. Chlamydia is a sexually transmitted disease. Those who are infected may or may not have symptoms. Both urine and urethral swab samples were taken from 816 men without signs of infection and 1,341 men with symptoms of infection. Four EIAs were evaluated. They included Chlamydiazyme, Kodak SureCell, Syva MicroTrak EIA and IDEIA. Results from the urethral swabs were compared with results from the EIAs. Six percent of the men without symptoms and 14% of the men with symptoms tested positive for chlamydial infection by the urethral swab tests. The EIAs detected from 82% to 91% of chlamydial infections. Chlamydia was detected less frequently in frozen urine samples. The urethral swab test detected approximately 90% of chlamydial infections.

Background and Objectives: Chlamydia trachomatis antigen testing of clinical specimens is replacing culture as the test of choice. Because of a potential for false positive results in low prevalence populations, there is an apparent need for confirming specimens positive by enzyme immunoassay (EIA). Goal of this Study: To examine specimens falsely positive in the Chlamydiazyme EIA assay according to gender and specimen type. Study Design: Testing of genitourinary specimens from men and women consecutively enrolled from five health care delivery sources in an urban Canadian population. All specimens were initially tested in the Chlamydiazyme test and all positives repeated in a confirmatory blocking assay provided by the manufacturer. Additional confirmatory testing was performed using immunofluorescence (IF) staining for C. trachomatis elementary bodies (EB's) and polymerase chain reaction (PCR). Results: From Jan. 1, 1990 to June 1, 1991, multiple specimens from 656 men and 5,628 women of varying population prevalences were screened. EIA-positive specimens from women had a repeat negative rate of 22% to 27% from cervical swabs and 29% from urethral swabs. Male urethral swabs had a high repeat negative rate of 22% when EIA was the only positive test, but 2.4% when the specimen was positive by EIA and culture. EIA-positive first void urine (FVU) specimens from men had a repeat negative rate of 8.7% as opposed to 17% to 32% from women. Only 1.7% (2/115) of male FVU did not block compared to rates of 47% (22/47) to 80% (4/5) in FVU from women. Analysis of EIA optical densities (OD's) and EB counts showed an association between the absorbance range 0.1 to 1.4 OD and 0-85 EB's. The greatest number of EB's and highest OD's were seen with cervical specimens, followed by urine and urethral specimens in women infected at all three specimens. All 55 specimens that did not confirm in the blocking test had no EB's and a convenience sample of seven were negative by PCR. All of a subset of 50 blocked specimens contained EB's or were positive by PCR. Conclusions: Although a variable proportion of specimens may not repeat positive in the EIA, use of the blocking reagent to confirm the repeat positives is highly recommended and the rate of blocking may be heavily influenced by gender and specimen type., Gender and specimen type may affect the prevalence of false-positive test results on the Chlamydiazyme enzyme immunoassay (EIA). The Chlamydiazyme EIA is a laboratory test used to diagnose infections of the urogenital tract caused by Chlamydia trachomatis. Researchers used different methods to test multiple specimens from 6,284 individuals who were initially tested for chlamydial infection using the Chlamydiazyme EIA. Twenty-two percent to 27% of the specimens taken from women by cervical swabs had false-positive results on the Chlamydiazyme EIA. Twenty-nine percent of the specimens taken from women by urethral swabs had false-positive results. In men, 22% of specimens taken from urethral swabs had false-positive results on the Chlamydiazyme EIA. False-positive test results were more prevalent among urine specimens taken from men than among those from women.

We evaluated the possible value of enzyme-linked immunosorbent assay (ELISA) using antigen 60 (A60) for improved diagnosis of tuberculosis in children. Results obtained in 31 children with active tuberculosis and [...]

Use of the ICON Strep B rapid immunoenzyme assay does not appear suitable for general screening of group B streptococcal infection. Severe group B streptococcal infections affect up to 15,000 newborn infants annually, most of which are acquired from the mother during delivery. The death rate from these infections is as high as 50% among premature infants. The new ICON Strep B immunoassay and the standard broth culture test were used to detect group B streptococcal colonization in vaginal samples taken from 424 pregnant women. Of 98 confirmed positive cultures, 90 showed light colonization. The Icon assay was positive in all eight women with heavy group B streptococcal colonization but was positive in only one of the 90 patients with light colonization. Of 79 of the infants born to women with light colonization, 19 were diagnosed with suspected streptococcal infection and three had severe infection.

To determine limitations in commonly used methods for detection of Chlamydia trachomatis, 601 genitourinary specimens from patients in a sexually transmitted disease clinic were examined with quantitative cultures and by 2 different direct antigen tests, immunofluorescence (Micro Trak; Syva Company, Palo Alto, CA) and enzyme immunoassay (Chlamydiazyme; Abbott Laboratories, North Chicago, IL). Genital specimens were held no longer than 5 hours (at 4 [degrees] C) prior to inoculation for culture; 28% (168/601) were positive. To evaluate the effect of storage on culture efficacy, duplicate specimens were also stored at -70 [degrees] C and brought out subsequently for culture a second time. Only 32% (8/25) of specimens cultured within 5 hours and having 100 inclusions; 50% (22/44) with 10-100 inclusions; and only 11% (6/53) with

An enzyme immunoassay (EIA; AntigEnz Chlamydia; Northumbria Biologicals, Northumberland, United Kingdom) and a polymerase chain reaction (PCR) assay (Genemed Biotechnologies, San Francisco, CA) were evaluated for the detection of Chlamydia trachomatis in urogenital specimens. Of 324 specimens, 23 were positive by cycloheximide-treated McCoy's cell culture method. Of 23 culture-positive specimens, 20 and 22 were found to be positive by EIA and PCR, respectively. Among 301 culture-negative samples, 4 were found to be positive by both PCR and EIA, 2 were PCR-positive and EIA-negative and 3 PCR-negative and culture-negative specimens were found to be positive by EIA. In comparing nonculture methods with cell culture technique, combined sensitives of 87.0% (90.9% in men and 83.3% in women) and 95.6% (90.9% in men and 100% in women), and specificities of 97.7% (99.4% in men and 95.7% in women) and 98.0% (99.4% in men and 96.5% in women) are achieved by EIA and PCR, respectively. The PCR proved to be the more sensitive of these two nonculture methods, and it can be used for the rapid diagnosis of C. trachomatis urogenital infection.

In order to resolve methodologic and interpretation problems associated with the serotyping of Neisseria gonorrhoeae isolates with monoclonal antibodies specific for Protein I (PI) by coagglutination (the standard method: CoA1), two methods were compared with CoA1: an enzyme immunoassay (EIA) and a modified coagglutination assay (CoA2), in which methylene blue was added to the monoclonal antibody reagents. When the EIA was compared with the CoA1 method, 92.7% of the WI isolates were typed identically and 89% of the WII/III isolates were typed identically. When the CoA2 was compared with the CoA1 method, 92.7% of WI isolates were typed into similar serovars, in comparison to only 80.5% of the WII/III isolates. With the EIA method, only 21 of 328 isolates (6.4%) were retested because duplicate results were inconsistent, in comparison to 72 isolates (22%) with the CoA1 method and 120 isolates (36.6%) with the CoA2 method. In most cases result inconsistencies between duplicate tests were due to differences in reading weakly positive coagglutination reactions with single reagents (which on duplicate testing might be negative), the most notable being PIA reagent 4A12(b) and PIB reagents 1F5(b) and 2G2(g). The EIA method was the most reproducible method, and provides some degree of automation when serotyping large numbers of isolates.

Genital Chlamydia trachomatis infection is believed to be the most prevalent sexually transmitted disease in the US. This sexually transmitted disease frequently goes unnoticed and is a major threat to health in women due to the clinical consequences, which include salpingitis, chronic pelvic pain, endometritis, ectopic pregnancy, and infertility. Although a variety of laboratory tests are used for the identification of C. trachomatis, many are not conclusive or accurate as a diagnostic tool for acute infection. A culture is the most accurate laboratory test for the diagnosis of this infection; however, it is expensive, not always available, and is not a rapid diagnostic tool. The enzyme-linked immunosorbent assay (ELISA) test has a high sensitivity (able to detect the organism 85 to 89 percent of the time) and a high specificity (able to differentiate the organism form others 95 to 97 percent of the time). A study was conducted to evaluate test-of-cure methods for genital C. trachomatis infections. Of 373 college-aged women who tested positive for C. trachomatis by ELISA, 75 were enrolled in a treatment study. Treatment with tetracycline 500 mg was prescribed four times a day for seven days. The ELISA test was performed 10 days following initiation of treatment. This method was a reliable test of cure for genital C. trachomatis infections in the women studied and resolution of the infection was confirmed by culture. (Consumer Summary produced by Reliance Medical Information, Inc.), 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. J FAM PRACT 1990; 31:36-41., Genital Chlamydia trachomatis infection in women has emerged as a problem of major public health importance. Although the true incidence of genital C trachomatis is unknown, it is now thought [...]

PURPOSE: An increased incidence of thrombosis has been reported in patients with a prolonged activated partial thromboplastin time (APTT) due to a lupus anticoagulant (LA), which is an antibody to negatively charged phospholipids. The antiphospholipid antibodies can be quantitated in an enzyme-linked immunoabsorbent assay (ELISA) that utilizes cardiolipin as the antigen. With the development of the ELISA, two major areas of controversy have arisen. First, the correlation between assay results for LA and for the ELISA has varied widely among laboratories. Second, some investigators have described a correlation between high levels of anticardiolipin antibodies (ACA) and thrombotic disorders, whereas others have found no association between ACA levels and thrombosis in a general population of medical patients. To explore these issues further, the present study determined the sensitivity and specificity of an LA assay for detecting ACA in medical patients with a prolonged APTT. The association between the isotype and titer of ACA and thrombosis was examined in those patients positive for LA. PATIENTS AND METHODS: Plasma samples from 70 medical patients with a prolonged APTT by routine screening studies were tested for the presence of LA by dilution of phospholipid in an APTT system and for IgM and IgG ACA according to a standardized ELISA. Clinical records were reviewed for a history of thrombotic events by an investigator who had no knowledge of the laboratory results. RESULTS: The ACA assay gave positive results in 47 patients, 44 of whom also tested positive for LA. Thus, the sensitivity for the LA assay for detecting ACA was 94 % (confidence interval, 82 % to 99 %). The result of the LA assay was negative in 20 of 23 patients who were ACA-negative. The specificity of the LA assay was 87 % confidence interval, 67 % to 98%). Twelve of the 47 patients (26%) had a history of venous or arterial thrombosis. Of these Patients, 75% tested in the high-positive range for IgG or IgM ACA, or both. Of the 35 patients without thrombosis, only 14% were in this range. Patients with thrombosis had either underlying systemic lupus erythematosus, lymphoma, or no apparent etiology for IA. There was no history of thrombosis in patients with LA associated with infection or medication. CONCLUSION: A test for LA in medical patients with a proloned APFT can be sensitive and specific for ACA. Determination Of ACA levels in patients who have LA that is not induced by medication or infection may define those patients at increased risk for thrombosis., Activated partial thromboplastin time (APTT) is the time required for a clot to form after the blood clotting factor thromboplastin, calcium and a phospholipid are added to a blood sample. Normal values range from 16 to 40 seconds, with prolonged times indicating blood clotting abnormalities. The incidence of thrombosis or blood clotting may be increased in patients with prolonged APTT due to a lupus anticoagulant (LA), an antiphospholipid antibody or specialized protein that specifically binds to and inactivates phosphate-containing compounds. The antiphospholipid antibodies can be measured using an immunological test called the enzyme-linked immunoabsorbent assay (ELISA) that uses cardiolipin as the phospholipid. However, studies have not consistently shown a correlation between direct measurements of LA and results from cardiolipin-dependent ELISA or an association between anticardiolipin antibodies (ACA) and thrombosis. The sensitivity and specificity of an LA assay for detecting ACA was evaluated in 70 patients with a prolonged APTT. The LA assay was shown to be 94 percent sensitive and 87 percent specific for detecting ACA. ACA were detected in 75 percent of 12 patients with thrombosis and 14 percent of 35 patients without thromboses. Patients with LA due to infection or medication had no thrombosis. The findings demonstrate that a test for LA in patients with prolonged APTT is sensitive and specific for measuring ACA levels, which may indicate the risk for thromboses in patients with LA unrelated to infection or medication. (Consumer Summary produced by Reliance Medical Information, Inc.)

Between 1985 and 1986, the drug zidovudine (also known as AZT) was shown to inhibit the human immunodeficiency virus (HIV), and it is used currently to treat acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC), which are caused by HIV infection. Two chemical methods, high-performance liquid chromatography (HPLC) and radioimmunoassay (RIA), have been used to determine the levels of zidovudine in body fluids. Two immunological methods, an enzyme-linked immunosorbent assay (ELISA) and a time-resolved fluoroimmunoassay (TR-FIA), which do not involve the use of radioactivity, were developed to determine zidovudine levels in the body. These newly developed methods may be well suited for laboratories not licensed to use radioactivity. Both ELISA and TR-FIA measure anti-AZT antibodies, which are immune system proteins that specifically bind to the drug AZT or zidovudine. Levels of AZT detected by anti-AZT antibody are then quantified by alkaline phosphatase enzyme activity in ELISA, and by degree of fluorescence, the emission of light upon exposure to ultraviolet radiation, in TR-FIA. The results show that the range of AZT levels that could be detected by ELISA was 125 to 4,000 nanomolar AZT, and by TR-FIA, 5 to 4,000 nanomolar. The speed and sensitivity of TR-FIA make it generally preferable to ELISA. Results obtained by ELISA, TR-FIA, HPLC, and RIA were consistent. (Consumer Summary produced by Reliance Medical Information, Inc.)