Vacutainer sst 2 advance tube

The Cobas Elecsys BRAHMS Procalcitonin immunoassay was introduced on 30 March 2020 for quantitative determination of procalcitonin;²² serum for this assay was collected in standard BD vacutainer^® SST II™ Advance tubes. Introduction of the assay was accompanied by dissemination of clinical guidance containing an institutional algorithm describing interpretation of procalcitonin results. This recommended that empirical antimicrobial treatment for respiratory tract infection could be stopped in patients with proven or suspected SARS-CoV-2 infection who had a procalcitonin level of ≤0.25 ng/mL. This cut-off was chosen to correspond with a conservative approach in a ‘moderate risk/acuity’ group of hospitalized patients.²³ (link) Results were not interpreted in isolation but rather as an adjunct to overall clinical judgement. A summary of the guidance is provided as Supplementary data (Section 2).

Fresh blood samples were collected in Vacutainer SSTII Advance tubes (BD Biosciences, Franklin Lakes, NJ, USA). Serum was collected as per manufacturer’s instructions, snap frozen in liquid nitrogen and stored at -80°C until further use. RNA was extracted from 240uL of serum using the miRcury RNA isolation kit for biofluids (Exiqon, Vedbaek, Denmark). At the first step of extraction, 300pg of a synthetic miRNA (Arabidopsis thaliana ath-miR-159a) was added to each sample as a spike-in.

MB and UCB were collected using BD Vacutainer^® SST™ II Advance tubes (BD Diagnostics, Franklin Lakes, NJ, USA). The blood samples were left for 15–20 min at room temperature to form a blood clot and then centrifuged for 12 min at a speed of 3500× g at 4 °C. The serum samples were divided into portions, transferred to 0.5 mL tubes, and stored at −80 °C until analysis.

The aim was to enroll 4500 subjects representative of the general population and 1000 subjects from key groups, either patients with potentially interfering conditions (pregnancy, systemic autoimmune diseases, hemodialysis) or at high risk of infection, including injecting drug users and patients with or at risk for sexually transmitted infections followed at a dermo-venereal clinics. All patients were 18 years old or higher and in a fasting status since at least 4 h and were consecutively enrolled among those who accessed the diagnostic centers of the Central Research Institute of Epidemiology (CRIE, Moscow) and Pasteur Research Institute of Epidemiology and Microbiology (Pasteur, St. Petersburg) to perform routine biochemistry analyses for non-infectious indications. All patients enrolled signed an informed consent form and the study was approved by ethics committees of both institutes. Samples were anonymized by a numeric code and the only demographic information recorded were sex and age. A single serum sample from each subject was collected in BD Vacutainer SST II Advance tubes with serum separator. After centrifugation (1500-2000 g, for 20 min at room temperature), each serum was divided in five aliquots of 1 mL each into Eppendorf tubes and stored at ≤ − 20 °C. Specimens were transported at the same temperature to CRIE, where all testing was performed.

Serum was obtained from peripheral blood in BD vacutainer SSTII advance tubes and centrifuged at 3500 rpm for 10 minutes. Samples were processed within 2 hours of collection and stored at −80°C until measurement. First freeze-thaw serum NfL was measured in duplicate using the R-plex NfL Meso Scale Discovery assay, according to the manufacturer’s instructions. The limit of detection (LOD) for the assay is 5.5 pg/ml with a working range of 12–50 000 pg/ml. For NfL levels below the linear range of detection, the equation LOD/√2 was applied, and a substitution value of 3.9 pg/ml was applied.^{20 (link)} The intra-assay coefficients of variation were <15%, and the inter-assay coefficients of variation were 3.5% and 6.5% for two pooled samples (n = 4 for each).

Peripheral blood was routinely sampled in 4-mL BD Vacutainer SST II Advance tubes (for serum collection) and in 4-mL BD Vacutainer EDTA K2E tubes (for plasma collection). The blood samples were incubated at room temperature for 20 to 60 min. After centrifugation at 1600xg for 10 min at 4°C, the supernatant (serum/plasma) was isolated and stored in aliquots at −80°C. Because of sample availability issues, the validation study was done on plasma specimens, whereas the exploratory screening was done on serum.

Serum was isolated from the patients’ blood stored in BD Vacutainer™ SST™ II Advance tubes (BD, Franklin Lakes, NJ, USA), after centrifugation at 1800× g for 10 min at room temperature and was transferred at −20 °C until use. IL-8 (Diaclone, Besancon Cedex, France) and TGF-β (R&D Systems, Minneapolis, MN, USA) were measured in the patients’ serum by ELISA. Total PSA in the patients’ serum was measured on the fully automated chemiluminescence immunoassay (CLIA) analyzer MAGLUMI 800 (Snibe Co., Ltd., Shenzhen, China).