Dimension xpand plus

A venous blood draw for TSB was done within 30 min of the TcB measurement. TSB was measured in the laboratory by a photometric technique using diazo methods. The hospital laboratory has two types of analyzers, Dimension Xpand Plus (Siemens, Germany) and Mindary BS 400 (China). TSB measurements were performed using either of these machines. The analyzers are always calibrated daily in the morning as part of the standard operating procedure of the laboratory.
The TcB measurements and TSB were entered onto a log sheet alongside with the following variables: gestational age, gender, age of infant and type of treatment given to patient (phototherapy, exchange transfusion or observe). The patients were managed according to WHO guidelines for management of jaundiced newborn.
Permission to conduct the study was obtained from Harare Hospital Ethics Committee Approval number HCHEC 200515/39. Written Informed consent was obtained from the parents.

Height and weight were obtained using standardised techniques and instruments. The body mass index (BMI) was calculated as the weight in kilograms divided by the square of the height in meters [weight (kg)/Height (m²)]. Fasting blood glucose levels were measured by the FreeStyle optimum glucometer (Abbott Diabetes Care, Australia). HbA1c levels were measured by the Bayer A1C Now⁺ Multi test A1C system (Catalog no.08842610). Creatinine (Siemens #DF33A) and uric acid (Siemens #BA4007) were measured by Siemens automated analyser (Dimension Xpand ^plus), estimated Glomerular Filtration Rate (eGFR) calculated from creatinine by using Modification of Diet in Renal Disease (MDRD) formula. Serum Insulin and C-peptide levels were measured by Bio-Rad Multiplex assay kit (Catalog:#171-A7001M). Assay was performed as per the manufacturer instructions.

Plasma β-HB and AcAc were measured by an automated colorimetric assay as previously described (6 (link)). Briefly, for AcAc, 25 μL of plasma was mixed with 330 μL of fresh reagent (Tris buffer, pH 7.0, 100 mM, 20 mM sodium oxamate; 0.15 mM NADH and 1 U/mL β-hydroxybutyrate dehydrogenase [β-HBDH]). For β-HB, the reagent was Tris buffer (pH 9.0; 20 mM sodium oxamate, 1 mM NAD, and 1 U/mL β-HBDH). Tris, oxamic acid, DL-β-HB sodium salt, Li-AcAc standard, and NAD were purchased from Sigma (St. Louis, MO, USA), NADH, from Roche (Mannheim, Germany), and β-HBDH from Toyobo (Osaka, Japan). The change in absorbance at 340 nm between 15 and 120 s after the addition of the reagent was measured on an automated clinical chemistry analyzer (Dimension Xpand Plus; Siemens, Deerfield, IL, USA). The assay was calibrated with freshly diluted standards from frozen aliquots of a 10 mM standard of Li-AcAc or DL-β-HB sodium salt, which is stable at −20°C for 2 and 6 months, respectively. Calibrations and quality controls were performed for each assay to ensure the precision of the assays (coefficient of variation between tests 5 ± 1%). Where plasma “total ketones” are reported, this refers to the total of AcAc and β-HB combined.

A Dimension^® Xpand Plus integrated clinical chemistry autoanalyzer (Siemens Healthcare Diagnostics, Deerfield, IL, USA) was used to perform and determine all parameters for biochemical and hormone studies listed in Table 1. The Friedewald equation was used to calculate the serum levels of low-density lipoprotein (LDL) cholesterol (17 (link)).

The complete blood count and blood chemistry profiles were performed at the Human Nutritional Chemistry Service Laboratory at Cornell University.  Hematology analysis was conducted using a Beckman-Coulter AcT Diff2 coulter counter; serum albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), glucose, total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides were measured using an automated chemistry analyzer (Dimension Xpand Plus; Siemens Healthcare Diagnostics).