S monovette 9.0 ml

Updated homeostasis model assessment indexes (HOMA2) values were calculated using fasting glucose and insulin levels assessed in the same day or within the previous 3 months of FGM fitting. Venous blood was collected from the antebrachial vein after a minimum 8 h overnight fast into EDTA tubes (S-Monovette 9.0 ml, K2 EDTA Gel, 1.6 mg/ml, Sarstedt). Blood glucose was measured in whole blood with a glucometer and converted into plasma glucose using the WHO conversion factor of 1.12 (FPG = WBG × 1.12)^{39 (link)}. Plasma insulin levels were measured by electrochemiluminescence sandwich immunoassay (ECLIA) (Cobas 8000, model e602, Roche Diagnostics, USA), against liquid human serum-based controls: Liquichek Immunoassay Plus Control, Level 1 #361 and Level 3 #363, Bio-Rad.

After an overnight 12-h fast, patients underwent a mixed-meal tolerance test (MMTT) with a standardized liquid meal (Fresubin Energy Drink, 200 ml, 300 kcal [50E% carbohydrate, 15E% protein and 35E% fat]; Fresenius Kabi Deutschland, Bad Homburg, Germany), based on macronutrient composition in accordance to post-bariatric surgery nutritional recommendations, as well as to allow comparisons with previous studies (15 (link), 17 (link)). Patients were instructed to abstain from alcohol consumption and strenuous physical activity the day before trial-days. Patients were requested to slowly drink the liquid meal over the first 15 min of the MMTT (grey shade in Figures), to assure consistency among subjects.
Peripheral venous blood sampling was performed using EDTA tubes (S-Monovette^® 9.0 ml, K2 EDTA Gel, 1.6 mg/ml, Sarstedt) at pre-established timepoints before and after the start of meal ingestion (baseline and 15, 30, 45, 60, 90, and 120 min), with simultaneous monitoring of pulse and blood pressure (BP). Samples were kept refrigerated until separation and plasma was stored at -20°C until analyzed.