Novel Application of Immunochromatographic Assay for Measurement of Total Tear Immunoglobulin E

PURPOSE

The aim of this study was to evaluate the efficacy of a new immunochromatographic assay (Aifeice) in the diagnosis of allergic conjunctivitis diseases (ACDs) and to explore the relationship between Aifeice testing results and the severity of ACDs.

METHODS

A multicenter prospective cross-sectional study (390 patients diagnosed with ACDs and 619 healthy controls) was conducted. Patients with ACDs were scored based on clinical symptoms. All participants received the Aifeice test. The positive testing results were further divided into 3 immunoglobulin E (IgE) grades. Statistical analysis was performed to evaluate the indexes associated with the testing results.

RESULTS

The sensitivity, specificity, positive predictive value, negative predictive value, and total coincidence rate of the Aifeice test were 96.15%, 98.87%, 98.17%, 97.61%, and 97.82%, respectively. The total clinical score was significantly correlated with the IgE grade. The factors that affected the IgE score were conjunctival hyperemia, conjunctival swelling, conjunctival papillae, and Horner-Trantas dots.

CONCLUSIONS

The high sensitivity and specificity of Aifeice in the diagnosis of ACD was confirmed. This new immunochromatographic assay could be used to assess the severity of ACD.

Comparison of the SARS-CoV-2 BD Veritor Nasal Antigen Test with Nasopharyngeal Reverse Transcription-PCR in Symptomatic Patients

This study evaluated the BD Veritor system for rapid detection of SARS-CoV-2, an immunochromatographic point-of-care test, by comparing it with a standard reverse transcription-PCR (RT-PCR) methodology using samples from symptomatic patients. Samples from 146 symptomatic and 2 asymptomatic patients between the 1st and the 40th day of infection were evaluated. The nasopharyngeal and/or oropharyngeal swabs were inserted in a tube containing 0.9% saline solution and stored at refrigerator temperature until the moment of use. The samples were first tested with the Xpert Xpress SARS-CoV-2 (GeneXpert) kit (RT-PCR method), and the cycle thresholds (C_Ts) for the E and N2 genes encoding the SARS-CoV-2 envelope and nucleoprotein, respectively, were established. Subsequently, the same samples were tested using the Veritor rapid test. We analyzed the C_Ts of the N2 gene, which is detected in both methodologies, and observed sensitivities of 100%, 98.8%, 89.6%, and 82.7% for the C_Ts of <25, <27, and <30 and all the C_Ts, respectively. The greatest sensitivity was observed when we performed the test on patients within 5 days of symptom onset. The BD Veritor system’s workflow is simple and fast, taking approximately 16 min from sample preparation to obtaining the test result. In addition to its satisfactory sensitivity, with results that correlate with those of the RT-PCR, the BD Veritor analyzer instrument reduces the subjectivity of unaided visual readings and consequent potential variation in result interpretation. Therefore, our results showed that the BD Veritor diagnostic test can provide a rapid and accurate diagnosis for SARS-CoV-2.

IMPORTANCE This study provides important and useful information, especially for diagnostic laboratories, since the results show that the BD Veritor system can provide a fast and safe point-of-care antigen diagnostic test for rapid detection of COVID-19 that has high sensitivity, reproducibility, and accuracy.

Immunochromatographic assays for ultrasensitive and high specific determination of enrofloxacin in milk, eggs, honey, and chicken meat

Enrofloxacin, a veterinary antibiotic that persists in food, poses a risk to human health. Here, a monoclonal antibody against enrofloxacin, 1H12, was prepared based on the hapten ENR-1, and showed excellent sensitivity with a 50% inhibitory concentration (IC₅₀) of 0.03 ng/mL. Using this antibody, 2 lateral-flow immunochromatographic assays were developed for determination of enrofloxacin in egg, milk, honey, and chicken meat samples. The detection ranges (IC₂₀-IC₈₀) were 0.16-0.82 ng/g, 0.24-1.8 ng/g, 0.25-3.6 ng/g, and 0.61-3.9 ng/g by colloidal gold-immunochromatographic sensor (CG-ICS) analysis, and 0.022-0.42 ng/g, 0.054-0.42 ng/g, 0.069-1.4 ng/g, and 0.19-2.2 ng/g by Eu-fluorescence-immunochromatographic sensor (EF-ICS) analysis. The intraassay and interassay recovery rates were 88.9 to 108.5% with coefficients of variation of 1.3 to 7.0% by CG-ICS analysis, and 88.6 to 113.6% with coefficients of variation of 1.3 to 8.1% by EF-ICS analysis. Thus, our newly developed ICS are sensitive and reliable, providing an option for rapid quantitative detection of enrofloxacin in food samples.

Comparison of real-time PCR assay with a commercial rapid test based on the immunochromatographic principle for the detection of Chlamydia trachomatis in seminal fluid and urine specimens

Chlamydia trachomatis is the most common sexually transmitted bacterial infection worldwide, with the highest prevalence in sexually active young women. Since most chlamydial infections are asymptomatic, facilitating the transmission of the pathogen in the population, regular screening is recommended for at-risk sexually active individuals. Hence, a sensitive, specific, inexpensive diagnostic test that can be executed efficiently and quickly to yield results would be helpful. In this study, we evaluated the performance (sensitivity and specificity) of the Chlamydia Rapid Test Device, an inexpensive rapid test based on immunochromatographic analysis. We then compared these results to those obtained using real-time PCR, the gold standard for C. trachomatis testing. Seminal fluid and urine specimens of male subjects were tested. The rapid test was applied to 220 seminal fluid samples, showing a sensitivity of 0%. On the other hand, used in 114 urine specimens, the rapid test showed 37.5% and 100% sensitivity and specificity, respectively. Hence, the Chlamydia Rapid Test Device was shown to be insufficiently sensitive to be recommended as a screening test and diagnostic method for the detection of C. trachomatis in symptomatic and asymptomatic subjects. Finally, the present investigation showed an infection prevalence of 5% calculated using seminal fluid, with a mean age of 28 years.

Foundation and Clinical Evaluation of a New Method for Detecting SARS-CoV-2 Antigen by Fluorescent Microsphere Immunochromatography

Purpose

To develop a rapid detection reagent for SARS-CoV-2 antigen for the auxiliary diagnosis of new coronary pneumonia (COVID-19), and perform the methodological evaluation and clinical evaluation of the reagent.

Method

SARS-CoV-2 N-protein test strip was created by combining fluorescent microsphere labeling technology and immunochromatographic technology, based on the principle of double antibody sandwich. Then we evaluated the analytical capability and clinical application of the strips.

Result

The limit of detection of the strips for recombinant N protein was 100 ng/ml and for activated SARS -CoV-2 virus was 1 × 10³ TCID₅₀/ml. The strips also have high analytical specificity and anti-interference capability. According to the predetermined cut-off value, the specificity of the test strip in healthy controls and patients with other respiratory disease was 100.00 and 97.29%, the sensitivity in COVID-19 cases at progress stage and cured stage was 67.15 and 7.02%. The positive percentage agreement and negative percentage agreement of antigen strip to RNA test were 83.16 and 94.45%.

Conclusion

SARS-CoV-2 fluorescence immunochromatographic test strip can achieve fast, sensitive and accurate detection, which can meet the clinical requirements for rapid detection of viruses on the spot.

Development of a Sensitive Immunochromatographic Method Using Lanthanide Fluorescent Microsphere for Rapid Serodiagnosis of COVID-19

The SARS-CoV-2 infection that caused the COVID-19 pandemic quickly spread worldwide within two months. Rapid diagnosis of the disease and isolation of patients are effective ways to prevent and control the spread of COVID-19. Therefore, a sensitive immunofluorescent assay method was developed for rapid detection of special IgM and IgG of COVID-19 in human serum within 10 min. The recombinant nucleocapsid protein of 2019 novel coronavirus was used as capture antigen. Lanthanide, Eu(III) fluorescent microsphere, was used to qualitatively/semiquantitatively determine the solid phase immunochromatographic assay. A total of 28 clinical positive and 77 negative serum or plasma samples were included in the test. Based on the analysis of serum or plasma from COVID-19 patients and healthy people, the sensitivity and specificity of the immunochromatographic assay were calculated as 98.72% and 100% (IgG), and 98.68% and 93.10% (IgM), respectively. The results demonstrated that rapid immunoassay has high sensitivity and specificity and was useful for rapid serodiagnosis of COVID-19.

Evaluation of a novel point-of-care test kit, ABSOGEN™ PCT, in semi-quantitative measurement of procalcitonin in whole blood

BACKGROUND

In response to inflammation, procalcitonin plasma concentrations increase more rapidly than other acute-phase reactants and higher values are associated with severe disease. Procalcitonin measurements assist in determining whether antibiotic therapy should be used. point-of-care testing (POCT) is performed for early decision making about additional testing or therapy. The ABSOGEN^™ PCT (Bumyoungbio, Inc., Suwon, Korea) is a rapid novel semi-quantitative immunochromatographic PCT assay that analyses whole blood samples. We compared the patient quantitative test results to ABSOGEN^™ PCT test results.

METHODS

Whole blood was loaded onto an ABSOGEN^™ PCT cartridge and incubated for 10 minutes. The color intensity of the band of the cartridge was measured using an accompanying device and with the naked eye. The results were graded as negative (<0.1 ng/mL), low (0.1 to <1.0 ng/mL), middle (1.0-2.0 ng/mL), and high (>2.0 ng/mL). A total of 158 specimens with procalcitonin levels measured from 0 to 18.96 ng/mL were used for comparison study.

RESULTS

The concordance rate between ABSOGEN^™ PCT using the reader and quantitative assay, between ABSOGEN^™ PCT using naked eyes and quantitative assay, and between ABSOGEN^™ PCT using the reader and naked eyes for the same category was 83.5% (P=.040), 78.5% (P<.001), and 82.3% (P=.001), respectively. The concordance rates for the ±1 categories were all 100%.

CONCLUSION

ABSOGEN^™ PCT is an accurate assay. It is easy to use, simple, fast, portable. The assay has potential value in clinical applications, especially in emergency care.

Development of a Rapid Immunochromatographic Strip Test for the Detection of Mulberroside A

INTRODUCTION

Mulberroside A (MuA) is the major active anti-tyrosinase compound in the root bark extract of Morus alba L. (Moraceae). Typically, MuA is widely employed as an active ingredient in whitening cosmetics. A rapid and simple assay system utilizing a small quantity of test sample is essential for the detection of MuA in large number of samples. An immunoassay using highly specific MuA polyclonal antibodies may be useful for the determination of small quantities of MuA in test samples.

OBJECTIVE

To establish a rapid qualitative MuA test, an immunochromatographic strip test was developed using anti-MuA polyclonal antibodies (anti-MuA PAb).

METHODOLOGY

The qualitative assay was based on a competitive immunoassay where the detection reagent consisted of anti-MuA PAb colored with colloidal gold particles. The capture reagent was a MuA-ovalbumin (MuA-OVA) conjugate immobilized on the test strip membrane.

RESULTS

A sample containing MuA and the detection reagent were incubated together with immobilized capture reagent on a nitrocellulose membrane. When MuA was present, it competed with the immobilized conjugates on the strip membrane to bind a limited amount of colored antibodies; thus, a positive sample showed no color on the capture spot zone. The detection limit for the strip test was 2 µg/mL. The developed immunochromatographic strip test was utilized to determine MuA in plants, medical preparations and cosmetic samples.

CONCLUSION

This immunochromatographic strip test is advantageous as a rapid, simple and sensitive screening method for the detection of MuA in plant extracts, cosmetic samples and pharmaceutical products.

Comparison of immunochromatographic diagnostic test with Hheminested Reverse transcriptase polymerase chain reaction for detection of rabies virus from brain samples of various species

AIM

Detection of rabies is a cause of serious concern in developing countries, where dearth of highly equipped laboratories and trained personnel to handle sophisticated investigations is felt. The availability of a diagnostic kit, which can be used in the field, is essential for diagnosis and control programs as well as for epidemiological surveillance of the prevalence of the disease. This study was planned to evaluate anigen rabies Ag test kit for its efficacy to be used for rapid diagnosis of rabies under field conditions. The test results were compared with hemi-nested reverse transcriptase polymerase chain reaction and with a gold standard fluorescent antibody test.

MATERIALS AND METHODS

A total of 34 brain samples from different rabies suspected animals including dogs, buffaloes, cow, horse, and cat were examined in this study.

RESULTS

Sensitivity of the kit was found to be 91.66%, specificity 100%, and accuracy was 94.11%.

CONCLUSION

The study implies that the immunochromatographic diagnostic test kit may be employed for diagnosis of rabies in field conditions.