Label-free quantification of host cell protein impurity in recombinant hemoglobin materials.

Quantitative analysis relies on pure-substance primary calibrators with known mass fractions of impurity. Here, label-free quantification (LFQ) is being evaluated as a readily available, reliable method for determining the mass fraction of host cell proteins (HCPs) in bioengineered proteins which are intended for use as protein calibration standards. In this study a purified hemoglobin-A2 (HbA) protein, obtained through its overexpression in E.

Determination of HbA by quantitative bottom-up proteomics and isotope dilution mass spectrometry.

Background: Poor comparability between laboratories is often observed in the measurement of HbA. A measurement procedure of higher metrological order is needed for value assignment to a reference material that shall be used as primary calibrator.

Method: A reference measurement procedure has been developed based on isotope dilution mass spectrometry (IDMS).

Developing a reference system for the IFCC standardization of HbA.

The importance of hemoglobin A (HbA) as an indicator of the presence of β-thalassemia was established many years ago. However, clinical application of recommended HbA cut off values is often hampered due to poor equivalence of HbA results among methods and laboratories. Thus, the IFCC standardization program for HbA was initiated in 2004 with the goal of achieving a complete reference system for this measurand.

Gaps in the traceability chain of human growth hormone measurements.

Background: Human growth hormone (hGH) is measured for the diagnosis of secretion disorders. These measurements fall under the EU Directive 98/79/EC on in vitro diagnostic medical devices requiring traceability of commercial calibrator values to higher-order reference materials or procedures (Off J Eur Communities 1998 Dec 7;L 331:1-37). External quality assessment schemes show large discrepancies between results from different methods, even though most methods provide results traceable to the recommended International Standard (IS 98/574).