BACKGROUND: Following discontinuation of the recombinant immunoblot assay (RIBA), the only available supplementary test for the detection of hepatitis C virus (HCV) is the nucleic acid amplification test (NAAT). However, the NAAT does not adequately detect past HCV. Consequently, it is hard to distinguish between past HCV infection and biological false positivity with an anti-HCV result alone. We assessed the diagnostic performance of two immunoassays: the ARCHITECT anti-HCV chemiluminescent microparticle immunoassay (CMIA; Abbott Diagnostics, Wiesbaden, Germany) and the Access HCV Ab PLUS chemiluminescent immunoassay (CIA; Bio-Rad, Marnes-la-Coquette, France). We also explored an optimized algorithm to determine the anti-HCV results. METHODS: We tested 126,919 patients and 44,556 individuals who underwent a medical checkup. RIBA and NAAT were conducted for samples that tested anti-HCV-positive using CMIA and CIA. We assessed the optimal signal-to-cutoff (S/CO) ratio in HCV-positive samples. RESULTS: In total, 1,035 blood samples tested anti-HCV-positive. Of these, RIBA was positive in 512, indeterminate in 160, and negative in 363 samples. One hundred sixty-five samples were NAAT-positive. Diagnostic sensitivity and positive predictive value (PPV) were 96.7% and 52.1%, respectively, for CMIA, and 94.7% and 72.3%, respectively, for CIA. The optimal S/CO ratio was 5.2 for CMIA and 2.6 for CIA at 95% PPV. In total, 286 samples tested positive in CMIA and 444 in CIA, while 443 samples tested positive in both assays. CONCLUSIONS: It is hard to determine anti-HCV positivity based on the S/CO ratio alone. However, this study elucidated the role of the S/CO ratio by using the NAAT and RIBA.
Hepacivirus ; Humans ; Immunoassay* ; Nucleic Acid Amplification Techniques*

Rolling circle amplification is a rapid, sensitive and isothermal single-stranded DNA amplification technique that can be used with staining or probes to amplify the detection signal. This technology has been widely used in biological detection and other aspects. The present paper introduces how to design rolling circle amplification, summarize its application in the detection of pathogens, nucleic acid tumor markers, proteins, biological small biomolecules, and viruses in recent years and prospects for future development.
DNA, Single-Stranded ; Nucleic Acid Amplification Techniques

In this study, the molecular marker technology of SRAP and ISSR were applied in rapid identification of seeds from eight species of Brassica oleracea L. Firstly, using the genomic DNA of cabbage as template, SRAP and ISSR reaction systems were optimized through testing every factor, respectively, that affects PCR amplification. Then, using the optimized reaction systems, 30 SRAP primer pairs and 15 ISSR primers were applied to amplify genomic DNA of cabbage, savoy, purple cabbage, borecole, cauliflower, broccoli, Brussels sprouts, and kohlrabi The results showed that high polymorphisms were exhibited among the eight species of Brassica oleracea L. by SRAP primer pairs of M3-E5 and M4-E5, as well as ISSR primers of 844 and 888, especially primer 844 which can identify all eight materials efficiently.
Brassica ; genetics ; Nucleic Acid Amplification Techniques ; methods ; Polymorphism, Genetic ; Repetitive Sequences, Nucleic Acid ; Seeds ; genetics

Prevalence of HIV infection in the Philippines remains low. This may be partly due to reliance on passive reporting for surveillance. The algorithm for laboratory testing for HIV infection has become more stringent in the sense that the screening assays are repeated in the confirmatory centers, before Western Blot is performed. This has been due to the high rate of false positives before 2005. Nucleic Acid Amplification testing (NAAT) has been performed routinely for blood banking purposes in other countries. In a few pilot studies, it has proven useful in identifying those cases in the early stage of the infection, which are missed on testing by antibody-based assays. The assay may prove useful in knowing whether false negatives happen with the current testing algorithm in the Philippines. Coupled with the detuned assay, identification of new cases may be critical for prevention of transmission, surveillance of cases, and early medical management if needed.

In May 2015, we conducted a voluntary online survey on laboratory diagnostic assays for Clostridium difficile infection (CDI) across clinical microbiology laboratories in Korea. Responses were obtained from 66 laboratories, including 61 hospitals and five commercial laboratories. Among them, nine laboratories reported having not conducted CDI assays. The toxin AB enzyme immunoassay (toxin AB EIA), nucleic acid amplification test (NAAT), and C. difficile culture, alone or in combination with other assays, were used in 51 (89.5%), 37 (64.9%), and 37 (64.9%) of the remaining 57 laboratories, respectively, and 23 (40.4%) of the laboratories performed all three assays. Only one laboratory used the glutamate dehydrogenase assay. Nine laboratories used the toxin AB EIA as a stand-alone assay. The median (range) of examined specimens in one month for the toxin AB EIA, NAAT, and C. difficile culture was 160 (50–2,060), 70 (7–720), and 130 (9–750), respectively. These findings serve as valuable basic data regarding the current status of laboratory diagnosis of CDI in Korea, offering guidance for improved implementation.
Clinical Laboratory Techniques ; Clostridium difficile ; Clostridium ; Glutamate Dehydrogenase ; Immunoenzyme Techniques ; Korea ; Nucleic Acid Amplification Techniques

Genetic Techniques ; Genomics ; Humans ; Nucleic Acid Amplification Techniques ; Nucleic Acid Hybridization ; Sequence Analysis, DNA ; Viruses ; genetics ; isolation & purification

Bacillus licheniformis alpha-amylase (BLA) is one of the most important enzymes involved in starch hydrolysis and many biotechnological processes. To improve the BLA productivity, an integrative plasmid pBL-amyL carrying amyL gene encoding a thermophilic alpha-amylase of B. licheniformis was constructed and transformed into B. licheniformis B0204, an industrial alpha-amylase producer. The transformants harboring different copies of amyL were developed on kanamycin by using homolog-mediated chromosomal amplification of alpha-amylase gene. The recombinants with different multiple copies of amyL integrated in the chromosome were identified by real-time PCR and evaluated by shake-flask fermentation. Recombinants harboring 2-5 multiple copies of amyL produced more alpha-amylase comparison to the parental strain B0204.
Bacillus ; enzymology ; genetics ; Gene Amplification ; Industrial Microbiology ; Nucleic Acid Amplification Techniques ; Transformation, Genetic ; alpha-Amylases ; biosynthesis ; genetics

BACKGROUND: Recombinant immunoblot assay (RIBA) or RNA test is considered to be a supplemental test for confirming a HCV infection. A correlation has been reported between the signal-to-cutoff (S/CO) ratios of a third generation HCV enzyme-linked immunosorbent assay (ELISA) and a confirmed HCV infection. This study examined the results of an evaluation of domestic anti-HCV EIA and immunoblot kit (RIBA) in Korean donors. METHODS: A total of 375,576 donor samples were tested for anti-HCV using the LG third generation HCV ELISA (LG HCD 3.0 TMB, LGphD, Korea) and HCV RNA by NAT (Biomerieux/Roche RT-PCR, 24 pool). The anti-HCV repeat reactive samples were further tested by third generation RIBA (LG HCD Confirm, LGphD, Korea). A positive result by either the nucleic acid amplification test (NAT) or RIBA was interpreted as a confirmed HCV infection. RESULTS: There were 506 out of the 375,576 donor samples (0.13%) that were anti-HCV repeat reactive (RR) by routine screening ELISA. The confirmed HCV prevalence in the donors was 0.01% (RIBA 42/375,570, RNA 36/375,570). 443 samples from the 506 repeat reactive samples in ELISA (87.6%) showed a S/CO ratio <3.0 but did not show positivity in the RIBA and RNA test. The rate of RIBA positivity in the RR specimens was 8.3% (42/506). The RNA detection rate in the RIBA positive samples was 85.7%(36/42). All 36 samples showing a positive result in both the RIBA and RNA test showed a significantly high S/CO ratio, >3.6 (mean 4.40+/-0.80), compared with the negative group (mean 1.54+/-0.64). CONCLUSION: There was a good correlation between a high S/CO ratios and a confirmed HCV infection. In addition, samples showing a low S/CO ratio with an ID (Indeterminate) or negative RIBA result suggest a high probability of nonspecific reactivity in ELISA.
Enzyme-Linked Immunosorbent Assay* ; Humans ; Mass Screening ; Nucleic Acid Amplification Techniques ; Prevalence ; RNA* ; Tissue Donors

BACKGROUND: Currently, serological assay, immunoblotting, and nucleic acid amplification test (NAT) are required as reentry tests for deferred donors with hepatitis C virus (HCV) or human immunodeficiency virus (HIV) screening reactive result. However, immunoblotting must be performed even for serological nonreactive donors. In this study, the efficacy of immunoblot applications for serological nonreactive donors in donor reentry procedures was examined. METHODS: We analyzed non-qualified donors with immunoblot results from 2011 to 2015 in Korea and investigated reentry procedures related with HCV or HIV in other countries. RESULTS: Percentages of donors who could not be released due to immunoblot results even with serological nonreactive results were 54.2% (1,824/3,367) for HCV and 35.9% (4,300/11,964). In the case of 662 donors, their results were considered to be different using other assay kits or based on other criteria. In other countries, immunoblotting is not required as a donor reentry test. CONCLUSION: Indeterminate or reactive immunoblotting results in serological nonreactive donors were due to nonspecific reactions. It is not reasonable to apply immunoblotting to serological nonreactive donors. Therefore, we suggest that immunoblot assays be excluded from the reentry test.
Hepacivirus ; HIV* ; Humans ; Immunoblotting ; Korea ; Mass Screening* ; Nucleic Acid Amplification Techniques ; Tissue Donors*

There has been continuous effort to prevent transfusion-transmitted infection (TTI). Strategies to prevent TTI can be divided into two components: first, determining donor eligibility, and second, managing bacterial contamination of blood products. To determine donor eligibility, medical history taking and screening tests for infectious diseases should be performed. To prevent bacterial contamination, blood collection process should be aseptic, tests for bacterial detection should be performed, and an application of pathogen reduction technology should also be considered. In this review, screening test items and methods, including nucleic acid amplification tests for determining donor eligibility, and precautions for blood collection, bacterial detection methods, and pathogen reduction technology for the prevention of bacterial contamination of blood products were discussed in detail.
Communicable Diseases ; Donor Selection ; Humans ; Mass Screening ; Medical History Taking ; Nucleic Acid Amplification Techniques ; Tissue Donors