Cypress, CA, United States
Cypress, CA, United States

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Prince H.E.,Focus Diagnostics Inc. | Lieberman J.M.,Focus Diagnostics Inc.
Clinical and Vaccine Immunology | Year: 2013

In conjunction with the 2012 Yosemite hantavirus outbreak, the number of sera our facility tested for hantavirus antibodies increased. We tracked test results and used the data set to determine if a more efficient testing algorithm was possible. Sera were screened using laboratory-developed pan-hantavirus IgG and IgM enzyme immunoassays (EIAs), with an index of>1.10 defined as positive. Sera that were IgM positive by screening (screen IgM+) were tested for Sin Nombre virus (SNV)-specific IgM using a laboratory-developed EIA; screen IgM+ IgG+ sera were also tested for SNV IgG using a laboratory-developed immunoblot assay. SNV antibody-positive samples were sent to state public health laboratories (PHL) or the CDC for confirmation. Of 3,946 sera tested from July through December 2012, 205 were screen IgM + IgG negative (IgG-); 7/205 were SNV IgM+, but only 1/5 sent to PHL/CDC was confirmed as SNV IgM+. Of 61 screen IgM+ IgG+ sera, 16 were SNV antibody positive; 13/16 sera (from 11 patients) went to PHL/CDC, where SNV infection was confirmed for all patients. Of 12 confirmed patients, 7 had been exposed at Yosemite. A modified algorithm defining screen indices of≥2.00 as positive identified 11/12 confirmed cases while reducing the number of sera requiring SNV-specific antibody testing by 65%; the patient missed was not tested until 3 months after the onset of symptoms. Hantavirus antibody testing at our facility identified 12 SNV-infected patients, including 7 exposed at Yosemite. Some screen IgM + IgG- SNV IgM+ results were false positives, emphasizing the value of PHL/CDC confirmatory testing. We identified a modified algorithm requiring analysis of fewer specimens for SNV-specific antibodies without loss of sensitivity. Copyright © 2013, American Society for Microbiology.


Prince H.E.,Focus Diagnostics Inc. | Matud J.L.,Focus Diagnostics Inc.
Clinical and Vaccine Immunology | Year: 2011

Dengue virus IgM persistence was estimated using follow-up sera from 98 patients (60 with primary infections and 38 with secondary infections) whose first-specimen IgM index was strongly positive, suggesting recent disease onset. Regression analysis of the follow-up IgM index versus days between samples yielded a trend line that reached the cut-point index (1.10) at 179 days for the primary infection group and 139 days for the secondary infection group. This difference reflected significantly higher first-sample IgM indices in primary infections than in secondary infections rather than differences in IgM decay rates. Copyright © 2011, American Society for Microbiology. All Rights Reserved.


Prince H.E.,Focus Diagnostics Inc. | Yeh C.,Focus Diagnostics Inc. | Lape-Nixon M.,Focus Diagnostics Inc.
Clinical and Vaccine Immunology | Year: 2011

Dengue virus (DV) IgM/IgG ratio and IgG avidity value (AV) can reliably distinguish between primary and secondary DV infections using sera collected within 30 days of disease onset, but little is known about their efficacies using sera collected >30 days after onset. To investigate this issue, we analyzed specimens submitted to our reference laboratory for DV antibody testing. We first classified patients as having primary (n ∇ 55) or secondary (n ∇ 58) infections based on seroconversion patterns in a comparison of two sera collected <30 days apart. We then evaluated IgM/IgG ratios and IgG AVs of the second specimens by using receiver operating characteristic curve analysis. The IgM/IgG ratio that best discriminated primary from secondary infection was 1.32; 95% of 55 primary infections exhibited ratios of >1.32, whereas 93% of 58 secondary infections exhibited ratios of ≤1.32. The discriminatory AV was 0.39; 95% of 41 primary infections exhibited AVs of ≤0.39, whereas 95% of 38 secondary infections exhibited AVs of >0.39. We then evaluated the IgM/IgG ratios and AV for primary-infection patients whose second serum samples were collected ≥30 days after the first serum samples; only 56% of 27 sera exhibited ratios of >1.32, whereas 81% of 21 sera exhibited AVs of ≤0.39. Assuming that the first specimens were collected within a week after symptoms appeared, these findings indicate that IgG AV is superior to the IgM/IgG ratio for distinguishing primary from secondary DV infections when using samples collected more than 5 weeks after disease onset. Copyright © 2011, American Society for Microbiology. All Rights Reserved.


Prince H.E.,Focus Diagnostics Inc. | Lieberman J.M.,Focus Diagnostics Inc. | Cherry J.D.,University of California at Los Angeles
Clinical and Vaccine Immunology | Year: 2012

During the period 2008 to 2010, we identified 11,386 serum samples with increased (positive) levels of antibodies recognizing Bordetella pertussis antigens. We sought to characterize the distribution of positive antibody result patterns in relation to patient age. IgG and IgA antibodies recognizing pertussis toxin (PT) and filamentous hemagglutinin (FHA) were quantified using a multianalyte immunodetection assay. Four mutually exclusive positive result patterns were observed: increased FHA antibodies only, increased PT IgA but not IgG, increased PT IgG but not IgA, and increased PT IgG and IgA. In patients <21 years old, the predominant pattern was increased PT IgG but not IgA, whereas in patients ≥21 years old, it was increased FHA antibodies only. The proportion of positive serum samples exhibiting increased PT IgA but not IgG was <20% in all age categories but showed a stepwise rise with age. The proportions of positive serum samples exhibiting increased PT IgG and IgA were similar (26 to 32%) in the age categories spanning 11 to 60 years of age but lower in the <11- and >60-year-old groups. In 3 of 5 age categories, a significant rise in the proportion of positive serum samples exhibiting increased FHA antibodies only occurred in 2010. Patterns of positive B. pertussis antibody results varied with age. The predominance of increased FHA antibodies only in patients >20 years old suggests that many adults thought to have B. pertussis infections actually have other infections that induce FHA-reactive antibodies. Similarly, the 2010 rise in the frequency of increased FHA antibodies only in some age groups suggests an increase in non-B. pertussis infections. Copyright © 2012, American Society for Microbiology. All Rights Reserved.


Prince H.E.,Focus Diagnostics Inc. | Yeh C.,Focus Diagnostics Inc.
Journal of Clinical Laboratory Analysis | Year: 2013

Background: Approximately 6% of sera positive in a dengue virus IgM-capture enzyme immunoassay (EIA) represent false-positives due to interaction between IgM and horseradish peroxidase (HRP)-labeled monoclonal antibody (MAb) 6B6C1 (IgG2a). To better understand this interaction, we assessed the reactivity of captured IgM from these sera with other HRP-labeled MAbs. Methods: Fifty dengue IgM false-positive sera (recognizing 6B6C1) were evaluated for IgM reactivity with the HRP-labeled MAbs H3A4 (IgG2a), 53.8 (IgG2b), and IL-A2 (IgG1). The sera were also tested in an EIA for human anti-mouse antibody (HAMA). Results: Forty-three sera (86%) reacted with IgG2a MAb (H3A4). Most (31/43 = 72%) of these sera recognizing 6B6C1 and H3A4 also recognized the IgG2 MAb and/or the IgG1 MAb. In contrast, HAMA was increased in only 9 of 50 (18%) sera reacting with 6B6C1. Conclusions: IgM from most sera-binding IgG2a MAb 6B6C1 also binds another IgG2a MAb, suggesting that IgM-6B6C1 reactivity is not idiotype specific. In many cases, IgM recognizing 6B6C1 also binds MAbs of other IgG subclasses, but is negative in a HAMA assay. These findings indicate that samples positive in IgM-capture EIAs utilizing conjugated MAbs should always be retested in the absence of antigen to identify false-positive reactivity caused by direct IgM-MAb interaction. © 2012 Wiley Periodicals, Inc.


Patent
Focus Diagnostics Inc. | Date: 2012-01-04

The invention provides methods for sensitive and specific detection of anti-HSV-2 antibodies by depletion of cross-reactive (non-specific) antibodies in a biological sample that can lead to a false positive result. The invention also features compositions, including nucleic acids, polypeptides, and kits, for use in the methods of the invention


Systems and methods for processing sample processing devices. The system can include a sample processing device comprising a detection chamber, a motor configured to rotate the sample processing device about an axis of rotation, and an optical module operatively positioned relative to the sample processing device and configured to determine whether a selected volume of material is present in the detection chamber of the sample processing device. The method can include rotating the sample processing device about an axis of rotation, and determining whether a selected volume of material is present in the detection chamber, while rotating the sample processing device. In some embodiments, determining whether a selected volume of material is present can be performed by optically interrogating the detection chamber for an optical property of the material.


Patent
Focus Diagnostics Inc. | Date: 2014-04-29

The invention provides methods and compositions for rapid, sensitive, and highly specific nucleic acid-based (e.g., DNA based) detection of a BK virus in a sample. In general, the methods involve detecting a target nucleic acid having a target sequence of a conserved region of BK viral genomes. The invention also features compositions, including primers, probes, and kits, for use in the methods of the invention.


Patent
Focus Diagnostics Inc. | Date: 2013-11-13

The invention provides methods and compositions for rapid, sensitive, and highly specific nucleic acid-based (e.g., DNA based) detection of a BK virus in a sample. In general, the methods involve detecting a target nucleic acid having a target sequence of a conserved region of BK viral genomes. The invention also features compositions, including primers, probes, and kits, for use in the methods of the invention. Preferably, the method distinguishes BK virus from JC and SV40 virus.


Trademark
Focus Diagnostics Inc. | Date: 2013-01-01

Assays for research purposes; diagnostic reagents for clinical and medical laboratory use; Diagnostic kits consisting primarily of monoclonal antibodies, buffers, and reagents to monitor drugs, medical conditions, and diseases for research purposes. Diagnostic kits consisting primarily of monoclonal antibodies, buffers, reagents and assay components for use in clinical and medical testing.

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