FAQ

Bridging between NPX Signature v1.x and NPX Signature v2.x is expected to work as established. Due to the change in intensity normalization calculation, bridging may result in larger adjustment factors, but this is expected and not indicative of poor bridging quality. Rather, it is a technical consequence of the slightly different NPX formula in NPX Signature v2.x.

Olink products are validated in human plasma and serum. Any other sample type such as urine, tissue lysate, or non-human samples are considered alternative matrices. 

For a specific assay within a plate:

where

σ_NPX = standard deviation of NPX for an assay across all sample controls

where

σ = standard deviation of an assay across all sample controls

and

μ = mean of an assay across all sample controls

LOD may be informative for technical evaluations, including CV calculations where it is recommended to base CV calculations on data > LOD.

However, it is recommended to include data < LOD in downstream statistical analyses as it does not increase the risk of false positive discoveries.

Our overall recommendation is not to impute the data and instead use a statistical method such as a mixed effect model which can handle missing data points. If you do want to impute, we recommend comparing the results from imputed and non-imputed data. In this case you can impute 0 for data below LLOQ and the ULOQ for data above ULOQ.

The interpretation of negative NPX depends on the type of normalization that is performed. For example, in plate control (PC) normalized data, zero NPX refers to the median of the PCs, while in intensity normalized data, zero NPX refers to the median of the samples. A negative NPX value in PC normalized data would mean that the NPX value for that sample in that assay is less than the NPX value of the median of the PCs for that assay. Regardless of the normalization method, negative values should still be included in downstream analysis. For more information, please contact our support team.

If sample has received quality control warnings, it is recommended to evaluate the sample further as detailed in Olink Analyze’s Outlier Exclusion tutorial. Depending on the reason for quality control warnings, the recommendation may differ, so consult with your Support representative for the right action for your data.

Olink Insight’s Stat Analyzer can be used for simple data analysis. For users with R experience, Olink Analyze has many functions to support downstream analysis. Olink also offers statistical analysis support as a service. For more information, please contact your sales representative.

For more information on UKBB we refer you to DNAnexus. Olink Insight’s data story and Olink Support can also aid in answering questions about UKBB methodology.

For NPX data generated on Target 96 and Explore, it is recommended to analyze the data sets separately followed by a meta-analysis rather than to bridge the data sets.

Data run on Explore 3072 can be combined with data from Explore HT if bridging samples are included on both projects. Olink recommends 40 to 64 bridging samples to bridge normalize the ~2900 overlapping assays. More information on bridging Explore 3072 to Explore HT can be found in Olink Analyze’s “Bridging accross NGS-based Olink products” tutorial.

Olink Explore HT consists of a single panel covering around 5400 protein biomarkers. The workflow uses a single PCR step instead of two, thus providing a more streamlined workflow. 172 samples are processed simultaneously, compared to 88 for Olink Explore 384/3072.

Customers can use either NPX™ Map Software or NPX™ Map CLI software to analyze Reveal, Explore HT and Explore 3072/384 data.

1. You need an established set of Olink biomarkers, from running Target or Exlore panels, defining your protein signature of interest.
2. You need to commit to run a minimum of 1 000 samples with the developed Focus panel.

The lead time for Focus panel development is 6 months.

The maximum number is 21 and the minimum number is 1. However, we encourage to make use of Olink’s big strength of multiplexing. The price for panel development will be the same for 1 or 21 assays.

For this purpose, Olink can develop several Focus panels.

No, only assays from Olink library can be utilized for Focus panel development.

Olink data are required for the Focus panel development. Our Custom development team uses this data in the theoretical feasibility phase to evaluate expected panel performance prior to project start.

All Focus panels are for Research Use Only (RUO).

Olink offers two products targeting murine proteins. The Target 96 Mouse Exploratory and Target 48 Mouse Cytokine panel. It has been shown that Target 96 Mouse Exploratory panel is also suitable to analyse rat proteins. For more information, refer to our Technical note “Extending Olink’s Mouse Exploratory panel to studies in rats” found on the documents page or contact the support team.