Comparative analysis of high CRP-levels in human blood using point-of-care and laboratory-based methods

The use of point-of-care (POC) methods and the measurements of C-reactive protein (CRP) as a diagnostic marker have both increased over the past years. This has led to an increase in POC-methods analysing CRP. High CRP levels are often seen as an indication for the subscription of antibiotics. The quality of POC-systems compared to routine diagnostic measurements for the analysis of CRP is thereby of main importance, since many small practises will use POC-methods. This study compared high-level CRP concentrations (above 100 mg/L) using an i-CHROMA^TM with 2 routinely used laboratory-based systems (Architect and ABX).

and Methods: A total of 199 patient samples with a CRP concentration above 100 mg/L were analysed with the i-CHROMA^TM POC system and the turbidimetric routine methods using the Architect and ABX equipment.

The results of the i-CHROMA^TM device showed a significant decrease in the CRP levels compared to those obtained with the Architect and the ABX (i-CHROMA^TM vs. Architect: y ​= ​0.6792x + 94.701; R² = 0.4980, i-CHROMA^TM vs. ABX: y ​= ​0.3674x + 118.05; R² ​= ​0.3964, Architect vs. ABX: y ​= ​0.7657x + 36.337; R² = 0.9311). Furthermore, data analysis showed a partition of the i-CHROMA^TM measurements in two defined clouds, which could not be explained with any of the available sample information.

This analysis showed the limitations of the i-CHROMA^TM CRP analyser. In addition, it illustrates the need for strict regulations on the information and output provided by companies regarding the boundaries of novel and existing diagnostic methods.