METHODS: Ninety five first-time male attendees of the Genito-urinary Medicine Clinic in Hospital Kuala Lumpur were included in this cross-sectional study. The detection of C. trachomatis was achieved through direct fluorescence antibody (DFA) staining of urethral swabs and real-time polymerase chain reaction testing (Xpert® CT/NG assay) on urine specimens. N. gonorrhoeae was detected through Gram staining and culture of urethral swabs and Xpert® CT/ NG assay on urine specimens.
RESULTS: From the Xpert® CT/NG results, 11 (11.6%) attendees had chlamydia, 23 (24.2%) had gonorrhoea and 8 (8.4%) had both STIs. The sensitivity and specificity of DFA in detecting chlamydia compared to Xpert® CT/NG were 5.3% (95% CI: 0-28) and 94.7% (95% CI: 86-98), respectively. For gonorrhoea, the sensitivity and specificity of Gram staining were 90.3% (95% CI: 73-98) and 95.3% (86-99), respectively, whereas the sensitivity and specificity of culture compared to Xpert® CT/NG were 32.2% (95% CI: 17-51) and 100% (95% CI: 93-100), respectively.
CONCLUSION: Although Gram-stained urethral swab smears are sensitive enough to be retained as a screening tool for gonorrhoea, culture as well as DFA lack sensitivity and are poorly suited to screen for gonorrhoea and chlamydia, respectively. However, owing to their high specificity, conventional detection methods are still suitable as confirmatory tests for gonorrhoea and chlamydia.
MATERIALS AND METHODS: A review of multiple reports and kit inserts on the diagnostic performance of rapid tests from various manufacturers that are commercially available were performed. Only preliminary data are available currently.
RESULTS: From a total of nine rapid detection test (RDT) kits, three kits offer total antibody detection, while six kits offer combination SARS-CoV-2 IgM and IgG detection in two separate test lines. All kits are based on colloidal gold-labeled immunochromatography principle and one-step method with results obtained within 15 minutes, using whole blood, serum or plasma samples. The sensitivity for both IgM and IgG tests ranges between 72.7% and 100%, while specificity ranges between 98.7% to 100%. Two immunochromatography using nasopharyngeal or throat swab for detection of COVID-19 specific antigen are also reviewed.
CONCLUSIONS: There is much to determine regarding the value of serological testing in COVID-19 diagnosis and monitoring. More comprehensive evaluations of their performance are rapidly underway. The use of serology methods requires appropriate interpretations of the results and understanding the strengths and limitations of such tests.
OBJECTIVE: We have conducted a multicenter clinical skin testing study to document the safety and diagnostic sensitivity and specificity of a candidate Hevea brasiliensis nonammoniated latex (NAL) extract. These data are intended to support the licensing of this reagent for the diagnosis of latex allergy in high-risk populations.
METHODS: Three hundred twenty-four subjects (304 adults and 20 children) were classified by their clinical history as having latex allergy (LA group, 124 adults and 10 children) or having no latex allergy (NLA group, 180 adults and 10 children). All subjects provided blood samples and then received sequential puncture skin tests (PSTs) at 1, 100, or 1000 microg/mL protein with a bifurcated needle and NAL (Greer Laboratories) from Malaysian Hevea brasiliensis (clone 600) sap. A 2-stage glove provocation test was used to clarify latex allergy status of individuals with positive history/negative PST result and negative history/positive PST result mismatches.
RESULTS: Twenty-four subjects (15%) originally designated as having LA on the basis of their initial clinical history were reclassified to the NLA group on the basis of a negative glove provocation test result. Of the 134 subjects with LA, 54 (40%) were highly sensitive to latex, with a positive PST result at 1 microg/mL NAL. The Greer NAL reagent produced a positive PST rate (sensitivity) of 95% and 99% in subjects with LA at 100 microg/mL and 1 mg/mL, respectively. The negative PST rate (specificity) in 190 subjects with a negative history with the NAL extract at 100 microg/mL and 1 mg/mL, was 100% and 96%, respectively. Immediately after the PST, mild systemic reactions (mainly pruritus) were recorded in 16.1 % of the adults in the LA group and 4.4% of the adults in the NLA group. No reactions required treatment with epinephrine. Only mild delayed reactions were observed in 9.6% (LA group) and 2.8% (NLA group) of subjects 24 to 48 hours after PST. Mean wheal and erythema diameters measured in the 10 children in the LA group with spina bifida at 100 microg/mL and 1 mg/mL were similar to those observed in the adults in the LA group, suggesting that children are not at increased risk for systemic reactions compared with adults.
CONCLUSIONS: A suggestive clinical history is necessary but not sufficient for a definitive diagnosis of IgE-dependent latex allergy. These data support the safety and diagnostic efficacy of the Greer NAL, skin test reagent at 100 micro/mL and 1 mg/mL for confirmatory PSTs.