Chromogranin-A Levels Measured with Automated Immunoassay

2015 ◽  
Vol 30 (1) ◽  
pp. 132-135 ◽  
Author(s):  
Damien Gruson ◽  
Thibault Lepoutre ◽  
Françoise Smits
Keyword(s):  
Cardiovascular Diseases ◽  
Risk Stratification ◽  
Immunosorbent Assay ◽  
Reference Values ◽  
Chromogranin A ◽  
Turnaround Time ◽  
Enzyme Linked Immunosorbent Assay ◽  
Neuroendocrine Neoplasms ◽  
Automated Assay ◽  
Automated Immunoassay

Measurement of chromogranin-A (CgA) levels is relevant for the diagnosis of neuroendocrine neoplasms. The use of CgA testing for risk stratification of cardiovascular diseases is also increasing. The objective of our study was to determine the performances and reference values of a novel automated assay for CgA testing. The new method was compared with an enzyme-linked immunosorbent assay. Our results showed that the performances of the automated assay were satisfactory and that the agreement between the two methods was excellent. The automation of CgA testing also reduced the turnaround time of analysis and, therefore, might contribute to a faster delivery of the results to physicians.

Enzyme-linked immunosorbent assay for chromogranin A.

1989 ◽  
Vol 35 (9) ◽  
pp. 1934-1938 ◽  
Author(s):  
L Dillen ◽  
J De Block ◽  
L Van Lear ◽  
W De Potter
Keyword(s):  
Monoclonal Antibody ◽  
Human Plasma ◽  
Immunosorbent Assay ◽  
Coefficient Of Variation ◽  
Chromogranin A ◽  
Enzyme Linked Immunosorbent Assay ◽  
Chromaffin Granules ◽  
Standard Curve

Abstract This is an enzyme-linked immunosorbent assay (ELISA) for determining chromogranin A (CGA) with use of a monoclonal antibody. CGA was isolated from bovine chromaffin granules. The analytical ELISA procedure for bovine CGA was developed and optimized. Typical standard curves ranged from 500 pg to 500 ng of CGA. We then studied human plasma CGA-immunoreactivity as measured by this assay. The curve for dilutions of human plasma paralleled the standard curve for bovine CGA. The intra-assay coefficient of variation for determination of human plasma CGA was 4.56%, indicating that reliable determinations can be performed for human plasma. However, further study revealed the presence of two CGA-immunoreactive substances in human plasma, one of which corresponds to the native CGA. The nature of the second immunoreactive substance still remains unknown. Nevertheless the measured CGA concentrations (ranging from 0.19 to 0.35 mg/L) in plasma are comparable with previously reported values.

scholarly journals Rapid Competitive Enzyme-Linked Immunosorbent Assay for Detection of Antibodies to Peste des Petits Ruminants Virus

2005 ◽  
Vol 12 (4) ◽  
pp. 542-547 ◽  
Author(s):  
Kang-Seuk Choi ◽  
Jin-Ju Nah ◽  
Young-Joon Ko ◽  
Shien-Young Kang ◽  
Nam-In Jo
Keyword(s):  
Immunosorbent Assay ◽  
Small Ruminants ◽  
Viral Disease ◽  
Turnaround Time ◽  
Enzyme Linked Immunosorbent Assay ◽  
Peste Des Petits Ruminants ◽  
Rinderpest Virus ◽  
Serum Samples ◽  
Specificity And Sensitivity ◽  
Relative Specificity

ABSTRACT Peste des petits ruminants (PPR) is a contagious viral disease of small ruminants that is of economic importance in Africa, the Middle East, and Asia. We developed a rapid competitive enzyme-linked immunosorbent assay (rapid c-ELISA) for the diagnosis and surveillance of PPR. This assay detects PPR virus (PPRV) antibodies in serum samples by quantifying the amount of monoclonal antibody (MAb) P-3H12 after 30 min of incubation of a serum-MAb conjugate mixture on plates coated with a PPRV recombinant nucleocapsid protein (rPPRV-N). We tested 249 PPRV-positive serum samples and 733 PPRV-negative serum samples from field ruminants. The threshold of percent inhibition (PI) was determined to be <50 on the basis of the mean PI plus 3 standard deviations for sera from PPRV-negative ruminants. The relative specificity and sensitivity of the rapid c-ELISA were 98.5% (722 of 733 serum samples) and 93.4% (234 of 249 serum samples), respectively. The rapid c-ELISA sensitively detected PPRV antibodies in hyperimmune sera (virus neutralization test [VNT] titer, >512), even at dilutions ≥512 in normal goat serum, and as early as 6 to 13 days postinfection from 12 goats, each of which was infected with one of the four PPRV lineages. Hyperimmune sera from animals experimentally vaccinated with rinderpest virus gave positive results by the rapid c-ELISA when the rinderpest virus VNT titers were >512, although the rapid c-ELISA titers were very low (2 to 16). However, the rapid c-ELISA was negative when the rinderpest virus VNT titer was ≤128. The rapid c-ELISA developed in the present work provides a short turnaround time and could be a useful tool for the diagnosis of PPR and screening for PPRV in the field.

Evaluation of the Candigen Enzyme-Linked Immunosorbent Assay for Quantitative Detection of Candida Species Antigen

2001 ◽  
Vol 125 (3) ◽  
pp. 344-346
Author(s):  
Sameer Elsayed ◽  
Viivi Fitzgerald ◽  
Viki Massey ◽  
Zafar Hussain
Keyword(s):  
Immunosorbent Assay ◽  
Candida Species ◽  
Clinical Utility ◽  
Turnaround Time ◽  
Assay Method ◽  
Quantitative Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Predictive Values ◽  
Disseminated Candidiasis ◽  
Culture Negative

Abstract Objective.—To assess the clinical utility of an enzyme-linked immunosorbent assay method for the quantitative detection of Candida species antigen (Candigen; Biomerica Inc, Newport Beach, Calif) in patients with suspected disseminated candidiasis. Methods.—Specimens of blood or cerebrospinal fluid from 75 patients with suspected disseminated candidiasis were analyzed by the Candigen test. Results were compared with those obtained by culture and polymerase chain reaction (PCR) analysis. Results.—Thirty-seven patients had specimens positive for Candida species by either culture or PCR. Of these specimens, 4 were positive by both culture and PCR, 21 were culture positive but PCR negative, and 12 were PCR positive but culture negative. Five specimens were positive by the Candigen test, all of which were PCR positive but culture negative. The sensitivity, specificity, and positive and negative predictive values of the Candigen test compared to culture plus PCR were 13.5%, 100%, 100%, and 54.3%, respectively. Turnaround time for the Candigen test was approximately 3 hours. Conclusion.—The Candigen test showed excellent specificity and turnaround time, but its poor sensitivity coupled with its inability to provide species information or susceptibility data make its clinical utility questionable.

Enzyme-linked immunosorbent assay for free thyroxin in human serum.

1989 ◽  
Vol 35 (8) ◽  
pp. 1770-1772 ◽  
Author(s):  
S H Chui ◽  
K C Wan ◽  
C W Lam ◽  
W H Lewis
Keyword(s):  
Human Serum ◽  
Immunosorbent Assay ◽  
Turnaround Time ◽  
Enzyme Linked Immunosorbent Assay ◽  
Microtiter Plates ◽  
Coefficients Of Variation ◽  
Radioimmunoassay Method

Abstract We describe a simple enzyme-linked immunosorbent assay (ELISA) in which microtiter plates are used for determining the free thyroxin concentration (FT4) in serum. Only commercially available chemicals and reagents are needed, including the antiserum. The working range is 1 to 60 ng/L. Turnaround time is about 4 h. Within-run coefficients of variation (CV) for FT4 concentrations of 9.0, 19.0, and 35.0 ng/L were less than 5%; between-run CVs were 10% to 11%. Results by a radioimmunoassay method for 150 sera correlated well (r = 0.922).

HEALTH-RELATED LIFESTYLE AND PATTERNS OF BEHAVIOR RELATED TO HEALTH EFFECTS OF LEISURE TRAVEL

2007 ◽  
Vol 35 (3) ◽  
pp. 287-294 ◽  
Author(s):  
Masahiro Toda ◽  
Hiroaki Makino ◽  
Hidetoshi Kobayashi ◽  
Kanehisa Morimoto
Keyword(s):  
Health Effects ◽  
Immunosorbent Assay ◽  
Salivary Cortisol ◽  
Chromogranin A ◽  
Enzyme Linked Immunosorbent Assay ◽  
Personal Health ◽  
Leisure Travel ◽  
Positive Effects ◽  
Health Related ◽  
Patterns Of Behavior

Whether or not leisure travel might have positive effects on personal health was investigated. During a short leisure trip, saliva samples were collected from 40 females. Levels of salivary cortisol and chromogranin A (CgA) were evaluated by enzyme-linked immunosorbent assay (ELISA). To quantitatively evaluate the health-related lifestyle and the patterns of behavior of the subjects, we also administered written questionnaires. For samples taken during the trip, there was a significant increase in the levels of CgA. Meanwhile, there was a significant increase in the levels of cortisol after the tour. These tendencies were more pronounced in individuals who scored well for health-related lifestyle. These findings suggest that the effects of travel were more beneficial for persons with positive characteristics related to health-related lifestyle.

scholarly journals Capture the Tag: Mitigation of Biotin Interference in ELISA and Automated Immunoassays by Pre-Conjugating Biotinylated Antibodies to the Streptavidin Surface

2021 ◽  
Vol 156 (Supplement_1) ◽  
pp. S4-S5
Author(s):  
Heather Nelson ◽  
Kelly Doyle ◽  
Sonia Laulu ◽  
Jun Lu
Keyword(s):  
Time Course ◽  
Interference Mitigation ◽  
Total Activity ◽  
Turnaround Time ◽  
Automated Assay ◽  
Assay Format ◽  
Patient Specimen ◽  
Biotin Binding ◽  
Analyte Detection ◽  
Automated Immunoassay

Abstract Introduction Streptavidin to biotin binding is one of the strongest non-covalent interactions in nature, and is therefore, successfully incorporated into many immunoassays to facilitate antibody capture. Biotin-streptavidin coupling assays are susceptible to interference from free biotin in patient specimens, which may falsely decrease or increase the result depending on assay format. Currently, biotin-stripping methods capture free biotin in patient specimens by pre-incubation with streptavidin-coated microparticles. However, this approach increases turnaround time, test cost, and testing steps, which increases the chance of error. Our objective was to determine if pre-conjugating biotinylated antibodies to the assay’s streptavidin solid surface before adding patient specimen could mitigate biotin interference in ELISA and automated sandwich immunoassays. Methods We performed this study on 3 different ELISAs (CYFRA-21, NSE, S100B) and one automated assay (thyroglobulin); all are a sandwich immunoassay format. Serum pools were spiked with biotin (25 - 1000 µg/L) or PBS control. Manufacturer protocols were followed in both the ELISAs and automated assay to evaluate baseline concentration-dependent biotin interference. Mitigation of biotin interference by pre-incubation was then evaluated in the ELISAs by adding biotinylated antibody to the streptavidin-coated wells 0, 10, 15, or 60 min before adding biotin- or PBS-spiked serum specimens. For the automated assay, streptavidin-coated beads and biotinylated antibody were removed from the reagent cartridge, mixed, and incubated 4.5 hours. The mixture containing biotin-tagged antibody bound to streptavidin beads was added back to the cartridge and placed on the analyzer to evaluate spiked specimens. Lastly, we compared the pre-incubation method to a standard biotin-stripping protocol in the ELISAs to compare the effectiveness of mitigating biotin interference. Results We observed biotin interference across the three ELISAs, where 400 µg/L biotin spiked in serum pools reduced analyte detection to between 10 – 15% of the total activity using the standard assay format. Our time-course studies showed 84 – 95% recovery of the total activity when the biotinylated antibody was pre-incubated in the streptavidin-coated wells for 1 hour prior to addition of serum specimens, compared to 69 – 99% by a standard biotin stripping protocol. We extended this concept to the automated immunoassay where at 1000 µg/L biotin in the specimen, only 9 ±0.01% of the total analyte was measured by the conventional method. However, pre-mixing biotinylated antibody and streptavidin beads resulted in 97 ±0.01% of the total analyte recovery in the presence of 1000 µg/L biotin. Conclusion We have demonstrated that pre-conjugating the biotin antibody to streptavidin is as effective as biotin-stripping methods to avoid biotin interference in sandwich immunoassays that utilize the biotin-streptavidin system, with the additional benefit of optimizing turnaround times, cost, and labor. A simple change in manufacturer assay design could make immunoassays more robust against biotin interference in patient samples.

Determination of myeloperoxidase in EDTA plasma: Comparison of an enzyme-linked immunosorbent assay with a chemiluminescent automated immunoassay

2009 ◽  
Vol 406 (1-2) ◽  
pp. 62-65 ◽  
Author(s):  
Sieglinde Zelzer ◽  
GholamAli Khoschsorur ◽  
Mariana Stettin ◽  
Gisela Weihrauch ◽  
Martini Truschnig-Wilders
Keyword(s):  
Immunosorbent Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Edta Plasma ◽  
Automated Immunoassay
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