Quality

Rekom Biotech is committed to ensure the highest quality level in the design and manufacturing of our IVD reagents. Our products are designed, developed, manufactured and distributed according to our Quality Management System, that is certified by ISO 9001 and ISO 13485 standards. Our IVD reagents are always manufactured according to Standard Operating Procedures (SOPs) and undergo rigorous quality controls in our laboratories. You can check our system policy if you please.

We are authorised to work with genetic modified organisms (GMO), with the license number A/ES/19/I-22, issued by National Biosafety Commission.

We are registered as a Innovative SME.

ISO 9001 certificate
ISO 9001 certificate
ISO 13485 certificate
ISO 13485 certificate
Genetic modified organisms (GMO)
Genetic modified organisms (GMO)
Innovate SME stamp
Innovate SME stamp

Quality controls

Each lot is subjected to various quality controls:

As the determination of accurate extinction coefficients is straightforward, ultraviolet absorption spectroscopy is preferred over chemical methods, such as the Lowry or Bradford methods. The measurement of the protein concentration is performed with the theoretical extinction coefficient of the recombinant protein obtained from Gill and vonHippel, 1989.

However, for proteins that do not contain any Trp residues, experience shows that this could result in more than 10% error in the computed extinction coefficient. Therefore, we measure the protein concentration by using the colorimetric assay based on the interaction between Coomassie brilliant blue and the arginine and aromatic residues (Bradford Method) with a maximum absorption shift from 470 nm to 595 nm (Bradford, 1976).

SDS-PAGE
SEC
SEC

Reproducibility analyses are performed by SDS-PAGE, SEC and ELISA assay. Excellent replicability of the production process.

SDS-PAGE analysis
SDS-PAGE analysis
ELISA analysis
ELISA analysis
SEC analysis
SEC analysis

Relative stability with immunoassay analysis at different ambient conditions is performed.

Storage Stability

For recombinant proteins produced in Pichia pastoris, the N-glycosylation and O-glycosylation are analysed.

N-Glycosylation
N-Glycosylation
O-Glycosylation
O-Glycosylation

For further information, take a look at our technical report Tritation Experiments.

ELISA assay
In this plot, the optical density at 450/620 nm for positive (blue) and negative (gray) IgG sera are compared for each concentration of the antigen. An appropriate statistical test of significance for the comparison of means between both groups, the Welch's test, is employed. Eligible concentrations for the use of the antigen should present statistically significant differences between positive and negative sera. This happens when the intervals at the top do not overlap and, equivalently, when the p-value at the bottom is below 0.05. In the present figure, all p-values are below 0.05 and thus the intervals do not overlap. Therefore, any of the showed concentrations can be used to distinguish between positive and negative sera.

Our in vivo monobiotinylated antigens are analysed with a western blot assay with conjugated streptavidin (A) and several ELISA assays (indirect ELISA assay in streptavidin-coated microtiter plates, capture ELISA assay with the biotinylated recombinant antigen as detector and double-antigen-sandwich ELISA assay (B)).

WB Assay
(A)
DAS Assay
(B)

As an internal quality control of an ELISA capture format, we also conjugate our antigens with peroxidase as internal quality control by using the biomarker as a developer. We perform a capture ELISA assay by using a commercial test and a double-antigen-sandwich ELISA assay.

A double antigen sandwich ELISA assay (DAS)
A double antigen sandwich ELISA assay (DAS) performed with positive and negative CMV IgM specimen sera pre-validated with the ELISA capture IgM VIDAS.
A capture ELISA assay

A capture ELISA assay performed with two different dilutions of the Rekom pp150-HRP in a reference commercial test (CMV-IgM-eLA test PKS medac).