Architect i2000sr analyzer

The 2021 serosurvey used a stratified, multi-stage cluster design with systematic sampling, with a sample size target of 8,010 adults (aged ≥ 18 years), and 2,692 children aged 5–17 years. The country was divided into 10 strata and 267 clusters, with 30 households per cluster chosen systematically. In each household, one adult and one child (in households with children) were randomly selected using a Kish grid [10 (link)]. Individuals were tested for anti-HCV using the anti-HCV chemiluminescent microparticleimmunoassay (CMIA) on a fully automated ARCHITECT i2000SR analyzer (Abbott Diagnostics, Wiesbaden, Germany). Positive samples were tested for HCV RNA by the Abbott RealTime HCV Assay (Abbott Molecular Inc., Des Plaines, Ilinoy (IL), United States (US)) on the Abbott m2000rt System (Abbott, Abbott Park, IL, US), and, if RNA was detected, genotyping was performed by the Abbott RealTime HCV Genotype II Assay with Abbott mSample Preparation System reagents (Abbott Molecular Inc., Des Plaines, IL, US) on the same Abbott m2000rt System. Final total enrolment was 7,237 adults and 1,473 children, with participation rates of 90.3% and 72.2%, respectively. Data were collected between June 2021 and October 2021 [6 (link)]. Serosurvey results were weighted by age and sex to be representative of the Georgian population.

Before and immediately following, the RT venous blood collections were performed in suitable vacutainers; tubes containing potassium ethylenediaminetetraacetic acid (K-EDTA) were used for testing cellular blood parameters. Tubes containing sodium-fluoride (NaF) were used for plasma glucose and lactate analysis, while native tubes were used to obtain serum in support of the routine laboratory blood tests.
All samples were transferred to the laboratory within 2 h, in which both plasma and serum were separated using centrifugation (15 min, room temperature, 1,500 g). Blood cell parameters were quantified in a multi-parameter automatic hematology analyzer, Sysmex XN-Series 9000 (Sysmex Corporation, Kobe, Japan). Plasma and serum parameters were measured using the Cobas 8000 Modular Analyzer (Roche Diagnostics, GmbH, Mannheim, Germany), while testosterone levels were measured using the ARCHITECT i2000SR Analyzer (Abbott Diagnostics, Abbott Park, IL, United States) in strict accordance with the manufacturer’s recommended guidelines.

Total homocysteine was assayed in plasma with a chemiluminescent microparticle immunoassay (Abbott Diagnostics, IL, USA). Plasma was diluted 1:10 or 1:5 with Multi-Assay Manual Diluent No. 7D82-50 (Abbott Diagnostics) prior to analysis by Architect i2000SR Analyzer (Abbott Diagnostics) at PathWest (WA, Australia).

The detection of IgG antibodies against SARS-CoV-2 was performed using the SARS-CoV-2 IgM and SARS-CoV-2 IgG II Quant assays, with the corresponding calibrators and controls for the ARCHITECT i2000SR analyzer (Abbott Diagnostics, Mississauga, ON, Canada). The ARCHITECT System uses chemiluminescent microparticle immunoassay (CMIA) technology as the detection method to measure and quantify the concentration of antibodies present in the serum. The SARS-CoV-2 IgG II Quant assay quantifies IgG in BAU/mL, since it is standardized according to the WHO standard. The IgG values were correlated with the WHO international standard 20/136, thus the units were expressed in BAU/mL (BAU: binding antibody units). The cut-off level of a positive IgG result was ≥7.1 BAU/mL. The levels of IgA against SARS-CoV-2 were analyzed in serum, using the DIAPRO COVID19 IgA Elisa KIT (Diagnostic Bioprobes Srl, Sesto San Giovanni, Italy) according to the manufacturer’s recommendations. The microplates were coated with immunodominant and nucleocapsid extender recombinant spike glycoproteins specific for COVID-19. The cut-off level of a positive IgA result was ≥1.1 AU/mL.

Blood samples were collected via a central venous catheter and urine samples were collected via a Foley catheter, at 0, 3, 6, 12, 24, and 48 h after admission to the burn intensive care unit. The blood NGAL levels were measured with the Triage NGAL reagent and Triage Meter (Alere Healthcare, San Diego, CA, USA). The serum cystatin C levels were measured according to a turbidimetric immunoassay method with the HiSense cystatin C kit (HBi, Anyang, Korea) and Hitachi 7600 analyzer (Hitachi, Tokyo, Japan). The serum and urine creatinine levels were measured according to an enzymatic method with the Cica Creatinine reagent (KANTO Chemical, Tokyo, Japan) and Hitachi 7600 analyzer (Hitachi, Tokyo, Japan).
For the urine NGAL analysis, urine specimens were transferred to centrifuge tubes and centrifuged at a relative centrifugal force ≥ 400 for a minimum of 5 minutes; the supernatants were stored at -70°C prior to batch analysis. After thawing, the specimens were mixed and centrifuged at 2,500 to 3,000 × g for 10 minutes prior to use, to remove any particulate matter and ensure consistency in the results. The urine NGAL levels were measured in a chemiluminescence immunoassay with an Architect i2000SR analyzer (Abbott Diagnostics, Abbott Park, IL, USA) and a dedicated urine NGAL reagent (Abbott Diagnostics). All measurements were performed according to the manufacturers’ instructions.