665. Lower Indeterminate Rates and Resolution by Retesting Using a Single Lithium-Heparin Tube Blood Collection Method for the QuantiFERON®-TB Gold Plus (QFT®-Plus)

Abstract Background The QuantiFERON-TB Gold Plus (QFT-Plus) test is an assay for detecting a cell-mediated immune response to M. tuberculosis (MTB). The assay measures the in vitro quantitative IFN-γ responses to MTB or control antigens in an incubated blood sample. There are 2 options for QFT-Plus blood collection. One option is a lithium-heparin transport tube with sample aliquots subsequently transferred to 4 QFT-Plus Blood Collection Tubes (1-tube QFT-Plus); the 2nd option is to directly collect the blood sample in 4 QFT-Plus collection tubes (4-tube QFT-Plus). In this study, we compared the indeterminate (IND) rates by the 2 blood collection methods to assess which method was superior. Methods For both blood collection methods, QFT-Plus ELISA testing was performed at various Quest Diagnostics sites as specified in the assay’s package insert. A retrospective data analysis of results for the above 2 blood processing methods was conducted. Also, we evaluated the rates of IND results in follow up blood collections. Statistical analyses were performed by the proportion test. Results In 2019, the IND result rate for greater than an 1.8 million 1-tube QFT-Plus draws was less than 1% whereas, the IND result rate for 0.3 million 4-tube draws was 4% This difference was significant. The overall MTB positive rate was 7% for the 1-tube method and 6% for the 4-tube method. Within a one-month interval following an initial blood collection event, 464 patients with an original IND result had a 2nd blood sample collected and tested. Only 35% of the 2nd blood collection events produced an IND result, with 52% of the 2nd sample results reporting as negative and 13% were positive. Conclusion This study found that the 1-tube QFT-Plus collection method reduces the IND rates by 4-fold compared to the observed rate in the 4-tube process. Additionally, two thirds of patients with an initial IND result resolved to either a positive or a negative result when retested within 1 month. Disclosures All Authors: No reported disclosures

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Optimization of a Whole-Blood Gamma Interferon Assay for Detection of Mycobacterium bovis-Infected Cattle

Clinical and Vaccine Immunology ◽

10.1128/cvi.00150-09 ◽

2009 ◽

Vol 16 (8) ◽

pp. 1196-1202 ◽

Cited By ~ 31

Author(s):

Irene Schiller ◽

W. Ray Waters ◽

H. Martin Vordermeier ◽

Brian Nonnecke ◽

Michael Welsh ◽

...

Keyword(s):

Carbon Dioxide ◽

Mycobacterium Bovis ◽

Whole Blood ◽

Intradermal Injection ◽

Gamma Interferon ◽

Blood Collection ◽

Cell Mediated Immune Response ◽

Delayed Initiation ◽

Ifn Γ

ABSTRACT Antigens of Mycobacterium bovis elicit a cell-mediated immune response upon intradermal injection in cattle. In vitro, such antigens stimulate the production of gamma interferon (IFN-γ) by bovine T cells in whole-blood culture (IFN-γ assay). We have analyzed various parameters of the in vitro IFN-γ assay, ranging from blood sampling to execution of the IFN-γ test, in view of potential simplifications of the assay. Here, we show that IFN-γ responses may be reduced under certain animal handling/holding conditions and that a delayed time from blood collection to culture may lead to a reduced in vitro IFN-γ response. Delayed initiation of culture in a purified-protein-derivative-based assay (24 h compared to 8 h after blood collection), however, resulted in a significant improvement of specificity (97% compared to 85%), whereas there was only a modest reduction of sensitivity (from 96% to 90%), which was statistically not significant. Furthermore, we show that the stimulation temperature needs to be 33°C or higher; that carbon dioxide is not required for stimulation; and that various plate formats, ranging from 24 to 96 wells per plate, can be utilized. The produced IFN-γ is stable at 4°C for 28 days as well as after repeated freeze-thaw cycles. Thus, stimulation of samples may be initiated in the field without the need for a carbon dioxide source, and bovine IFN-γ is stable under various routine laboratory temperature scenarios. These findings demonstrate opportunities for improvements in the bovine IFN-γ test platform and flexibilities in test application.

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Aggregation of Cat Platelets in Vitro

Thrombosis and Haemostasis ◽

10.1055/s-0038-1654191 ◽

1970 ◽

Vol 23 (03) ◽

pp. 601-620 ◽

Cited By ~ 14

Author(s):

Th. B Tschopp

Keyword(s):

Adenosine Monophosphate ◽

Blood Collection ◽

Base Line ◽

Reversible Aggregation ◽

Low Concentrations ◽

Irreversible Aggregation ◽

High Concentrations ◽

Two Phases ◽

Improved Technique

SummaryAggregation of cat platelets in the citrated plasma is examined by means of Born’s absorptiometer. A marked tendency of the platelets of this species to spontaneous aggregation necessitated first of all the development of an improved technique of blood collection.A hypothesis according to which 5-HT is released from the platelets, explains the absence of oscillations on the base line of the absorptiometer, the absence of platelet swelling, when ADP is added, and the effect of stirring on the aggregation curves in cat PRP. The average volume of cat platelets amounts to 10.46 μ3 when directly fixed in the blood, when fixed from PRP to 12.17 μ3, when fixed from stirred PRP to 13.51 μ3.In low concentrations (0.3-2 μM) ADP produce reversible aggregation; in narrowly restricted, individually dissimilar mean concentrations irreversible aggregation in two phases and in high concentrations, irreversible aggregation in one phase. Like ADP serotonin produces 2 phase irreversible aggregation in concentrations of 3-10 μM, but unlike ADP, the aggregation velocity decreases again with high 5-HT concentrations (>100 μM). Adrenaline does not produce aggregation and it is likely that adenosine and adenosine monophosphate inhibit the aggregation by serotonin but not by ADP. Species differences in the aggregation of human, rabbit and cat platelets are discussed.

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A Simple and Rapid Method to Determine GPIIb/IIIa-Receptor Inhibitor Activity in Whole Blood

Hämostaseologie ◽

10.1055/s-0038-1660401 ◽

1999 ◽

Vol 19 (03) ◽

pp. 134-138

Author(s):

Gitta Kühnel ◽

A. C. Matzdorff

Keyword(s):

Flow Cytometry ◽

Platelet Count ◽

Blood Sample ◽

Platelet Activation ◽

Whole Blood ◽

Receptor Occupancy ◽

Aggregate Formation ◽

Inhibitor Activity ◽

Receptor Inhibitor

SummaryWe studied the effect of GPIIb/IIIa-inhibitors on platelet activation with flow cytometry in vitro. Citrated whole blood was incubated with increasing concentrations of three different GPIIb/IIIa-inhibitors (c7E3, DMP728, XJ757), then thrombin or ADP were added and after 1 min the sample was fixed. Samples without c7E3 but with 0.1 U/ml thrombin had a decrease in platelet count. Samples with increasing concentrations of c7E3 had a lesser or no decrease in platelet count. The two other inhibitors (DMP 725, XJ757) gave similar results. GPIIb/IIIa-inhibitors prevent aggregate formation and more single platelets remain in the blood sample. The agonist-induced decrease in platelet count correlates closely with the concentration of the GPIIb/IIIa inhibitor and receptor occupancy. This correlation may be used as a simple measure for inhibitor activity in whole blood.

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The past, present and future of food consumption databases

Orvosi Hetilap ◽

10.1556/oh.2012.29475 ◽

2012 ◽

Vol 153 (43) ◽

pp. 1692-1700

Author(s):

Viktória Szűcs ◽

Erzsébet Szabó ◽

Diána Bánáti

Keyword(s):

Data Collection ◽

Food Consumption ◽

Age Groups ◽

Collection Method ◽

The Past ◽

Consumption Data ◽

Food Consumption Data ◽

International Projects ◽

Collection Methods ◽

The Eu

Results of the food consumption surveys are utilized in many areas, such as for example risk assessment, cognition of consumer trends, health education and planning of prevention projects. Standardization of national consumption data for international comparison is an important task. The intention work began in the 1970s. Because of the widespread utilization of food consumption data, many international projects have been done with the aim of their harmonization. The present study shows data collection methods for groups of the food consumption data, their utilization, furthermore, the stations of the international harmonization works in details. The authors underline that for the application of the food consumption data on the international level, it is crucial to harmonize the surveys’ parameters (e.g. time of data collection, method, number of participants, number of the analysed days and the age groups). For this purpose the efforts of the EU menu project, started in 2012, are promising. Orv. Hetil., 2012, 153, 1692–1700.

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Development of a blood sample detector for multi-tracer positron emission tomography using gamma spectroscopy

EJNMMI Physics ◽

10.1186/s40658-019-0263-x ◽

2019 ◽

Vol 6 (1) ◽

Cited By ~ 1

Author(s):

Carlos Velasco ◽

Adriana Mota-Cobián ◽

Jesús Mateo ◽

Samuel España

Keyword(s):

Positron Emission Tomography ◽

Blood Sample ◽

Pet Imaging ◽

Spectroscopic Analysis ◽

Gamma Spectroscopy ◽

Emission Tomography ◽

Blood Samples ◽

Positron Emission

Abstract Background Multi-tracer positron emission tomography (PET) imaging can be accomplished by applying multi-tracer compartment modeling. Recently, a method has been proposed in which the arterial input functions (AIFs) of the multi-tracer PET scan are explicitly derived. For that purpose, a gamma spectroscopic analysis is performed on blood samples manually withdrawn from the patient when at least one of the co-injected tracers is based on a non-pure positron emitter. Alternatively, these blood samples required for the spectroscopic analysis may be obtained and analyzed on site by an automated detection device, thus minimizing analysis time and radiation exposure of the operating personnel. In this work, a new automated blood sample detector based on silicon photomultipliers (SiPMs) for single- and multi-tracer PET imaging is presented, characterized, and tested in vitro and in vivo. Results The detector presented in this work stores and analyzes on-the-fly single and coincidence detected events. A sensitivity of 22.6 cps/(kBq/mL) and 1.7 cps/(kBq/mL) was obtained for single and coincidence events respectively. An energy resolution of 35% full-width-half-maximum (FWHM) at 511 keV and a minimum detectable activity of 0.30 ± 0.08 kBq/mL in single mode were obtained. The in vivo AIFs obtained with the detector show an excellent Pearson’s correlation (r = 0.996, p < 0.0001) with the ones obtained from well counter analysis of discrete blood samples. Moreover, in vitro experiments demonstrate the capability of the detector to apply the gamma spectroscopic analysis on a mixture of 68Ga and 18F and separate the individual signal emitted from each one. Conclusions Characterization and in vivo evaluation under realistic experimental conditions showed that the detector proposed in this work offers excellent sensibility and stability. The device also showed to successfully separate individual signals emitted from a mixture of radioisotopes. Therefore, the blood sample detector presented in this study allows fully automatic AIFs measurements during single- and multi-tracer PET studies.

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Comparison of rectal swab, glove tip, and participant-collected stool techniques for gut microbiome sampling

BMC Microbiology ◽

10.1186/s12866-020-02080-3 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Meghan I. Short ◽

Robert Hudson ◽

Benjamin D. Besasie ◽

Kelly R. Reveles ◽

Dimpy P. Shah ◽

...

Keyword(s):

Prostate Cancer ◽

Gut Microbiome ◽

Rectal Swab ◽

Prostate Cancer Screening ◽

San Antonio ◽

Collection Method ◽

Gold Standard Method ◽

Linear Discriminant ◽

Home Based ◽

Collection Methods

Abstract Background Studies of the gut microbiome are becoming increasingly important. Such studies require stool collections that can be processed or frozen in a timely manner so as not to alter the microbial content. Due to the logistical difficulties of home-based stool collection, there has been a challenge in selecting the appropriate sample collection technique and comparing results from different microbiome studies. Thus, we compared stool collection and two alternative clinic-based fecal microbiome collection techniques, including a newer glove-based collection method. Results We prospectively enrolled 22 adult men from our prostate cancer screening cohort SABOR (San Antonio Biomarkers of Risk for prostate cancer) in San Antonio, TX, from 8/2018 to 4/2019. A rectal swab and glove tip sample were collected from each participant during a one-time visit to our clinics. A single stool sample was collected at the participant’s home. DNA was isolated from the fecal material and 16 s rRNA sequencing of the V1-V2 and V3-V4 regions was performed. We found the gut microbiome to be similar in richness and evenness, noting no differences in alpha diversity among the collection methods. The stool collection method, which remains the gold-standard method for the gut microbiome, proved to have different community composition compared to swab and glove tip techniques (p< 0.001) as measured by Bray-Curtis and unifrac distances. There were no significant differences in between the swab and glove tip samples with regard to beta diversity (p> 0.05). Despite differences between home-based stool and office-based fecal collection methods, we noted that the distance metrics for the three methods cluster by participant indicating within-person similarities. Additionally, no taxa differed among the methods in a Linear Discriminant Analysis Effect Size (LEfSe) analysis comparing all-against-all sampling methods. Conclusion The glove tip method provides similar gut microbiome results as rectal swab and stool microbiome collection techniques. The addition of a new office-based collection technique could help easy and practical implementation of gut microbiome research studies and clinical practice.

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RISTOMYCIN (AGGRISTIN) PRECIPITATION TEST: A NEW, RAPID AND RELIABLE METHOD FOR THE DETECTION OF INTRAVASCULAR CLOTTING

10.1055/s-0038-1643133 ◽

1987 ◽

Author(s):

G Pfliegler ◽

J Arnout ◽

J Vermylen

Keyword(s):

Reliable Method ◽

Degradation Products ◽

Laboratory Diagnosis ◽

Blood Collection ◽

Vein Thrombosis ◽

Fibrin Degradation Products ◽

Acid Citrate Dextrose ◽

Citrate Dextrose ◽

Precipitation Test

The rapid and specific detection of fibrin monomers (fm) and fibrin degradation products (fdp) is of major importance in the laboratory diagnosis of disseminated intravascular coagulation, deep vein thrombosis or pulmonary embolism. Most methods in use are either time-consuming, needing special techniques, or insensitive and poorly specific. Some time ago, Watanabe and Tullis described a simple and rapid, semiquantitative test to detect fm and fdp in plasma, based on the finding that ristocetin in low concentrations (1.0-1.5 mg/ml) can specifically precipitate fm and fdp. To 0.4 ml ACD plasma, 0.1 ml ristocetin (2.5 mg/ml) is added and vortexed. The mixture is then incubated for 30 min at 20°C and centrifuged at 50xg for 5 min. The test is considered to be positive when fibrin-like strands or small or large pellets are observed on the bottom of the tube. More recently, Pfliegler et al. reported that ristomycin (AGGRISTIN), a structural analogue of ristocetin, can replace ristocetin in this test.Here we report on further results with the ristomycin (AGGRISTIN) precipitation test in 138 patients with various intravascular thrombotic events. The results of this test, performed on ACD plasma, were compared to the serum fdp values detected by immunoelectrophoresis (IEF) and by the haemagglutina-tion inhibition test (HIT). In all 30 cases with serum fdp above 30 ug/ml (HIT) or 28 pg/ml (IEF), the precipitation test was positive; at lower fdp concentrations, as detected by HIT or IEF, the test still was positive in 70 per cent of these thrombosis patients, suggesting a superior sensitivity. In 16 patients with elevated fibrinogen levels (but no evidence of thrombosis), the test was positive in only 3. No false positive results were detected in 16 healthy controls. Preliminary results show that the minor disadvantage of the test (blood collection on acid citrate dextrose) may readily be overcome by the in vitro adjustment of the pH of citrate plasma, commonly used for other haemostatic tests, to between 7.0 and 7.4.On the basis of our results we suggest that the AGGRISTIN (ristomycin) precipitation test is a simple, rapid and reliable method for the laboratory diagnosis of intravascular clotting.

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