Nf light elisa kit

For ELISA analysis of CSF samples, we used the NF-light^® ELISA Kit (Uman Diagnostics, Umeå, Sweden; catalog number: 10-7002), which has been previously validated for CSF samples. Intra- and inter-assay coefficients of variability (CV%) were <5 and <10, respectively. The measuring range was 100−10.000 pg/mL, with a limit of detection at 33 pg/mL. Before the analyses, all CSF samples were diluted with sample diluent at a ratio of 1:2.
For ELISA analysis of serum samples, we used the Human Neurofilament Light Polypeptide ELISA Kit (Abbexa, Abbexa Ltd, Cambridge, UK; catalog number: abx152468). Intra- and interassay CV% were <10 and <12, respectively. The measuring range was 15.6−1.000 pg/mL, and the limit of detection was < 6.2 pg/mL.
For SIMOA analysis, high-sensitivity SIMOA^® NF-Light assay (Quanterix Corp., Billerica, MA, USA) was used for both serum and CSF analysis. All analyses were performed on the HD-X Analyzer™ by running the samples in duplicate. Intra- and interassay CV% were within acceptable limits, with a limit of detection at 0.038 pg/mL. SIMOA analyzes were performed at the Neuroimmunology Laboratory of the University Hospital Basel, Switzerland.

cNfL was analyzed using a sensitive sandwich enzyme-linked immunosorbent assay (ELISA) method (NF-light^® ELISA kit; UmanDiagnostics AB, Umea, Sweden; catalogue # 10-7001 CE) and age-adjusted upper limits of the reference range utilized in clinical practice were used in order to determine whether cNfL levels were elevated or normal, as previously described (28 (link)). These upper limits are: <380 ng/L (<30 years), <560 ng/L (30-39 years), <890 ng/L (40-60 years), and <1850 ng/L (>60 years).

Clinical laboratory assessments of CSF WBC and CD4+ T-lymphocyte count were performed at each participating site. Plasma and CSF HIV-1 RNA was quantified using RT-PCR (Amplicor® version 1.5, Roche Diagnostic Systems) with a lower limit of quantification of 50 copies/ml.
For CSF biomarker analysis, we used cell-free specimens of CSF stored at -80°C and not thawed until analysis. CSF NFL was measured using a sandwich ELISA method with a lower limit of quantification of 50 ng/l (NF-light® ELISA kit, UmanDiagnostics AB, Umeå, Sweden) at the Clinical Neurochemistry Laboratory at the University of Gothenburg according to the manufacturers description. CSF NFL concentrations have previously been shown to increase with normal ageing in healthy individuals [12 (link)]. The upper normal reference limits of CSF NFL previously established using CSF samples from 108 neurologically healthy control individuals were <380 ng/l (18–29 years), <560 (30–39 years), <890 (40–59 years), <1850 (>59 years). CSF neopterin was analyzed using a commercially available immunoassay (BRAHMS, Berlin, Germany), with an upper normal reference value of 5.8 nmol/l [22 (link)].