In the field of clinical biochemistry, the accurate measurement of serum creatinine is paramount in assessing kidney function and diagnosing renal diseases. Conventional methods for serum creatinine quantification have been hampered by several issues, such as creatine-creatinine interconversion during sample pretreatment, which can potentially lead to inaccurate results. However, a breakthrough has recently been documented in ‘Clinica Chimica Acta’, detailing a new candidate reference method showing promise in correcting these conversion errors (DOI: 10.1016/j.cca.2024.117778).
This pioneering study spearheaded by the team from the Department of Physical and Analytical Chemistry at the University of Oviedo, Spain, presents an advanced analytical technique that utilizes bidimensional liquid chromatography coupled to electrospray ionization-tandem mass spectrometry (ESI-MS/MS) and a double-spike isotope dilution. With promising findings reported on January 14, 2024, in an article bearing the identifier S0009-8981(24)00019-6, the technique is presented as a beacon of precision in the biochemical analysis of serum creatinine.
The study, led by researchers Daniela Pineda-Cevallos, María Funes Menéndez, Adriana González-Gago, Pablo Rodríguez-González, and J. Ignacio García Alonso, has revealed significant advantages over existing practices. It minimizes spectral interferences and ion suppression, which have traditionally plagued the precision of such measurements due to matrix effects. Moreover, it offers an increase in sample throughput, an aspect crucial for high-demand clinical settings.
Through their diligently crafted approach, the research team has successfully overcome one of the most persistent issues in serum creatinine determination: the interconversion between creatine and creatinine. In long-standing methods, the creatine present in serum samples could convert to creatinine during preparation and handling, leading to false elevations in creatinine levels. This is notably problematic as accurate creatinine levels are essential for the calculation of glomerular filtration rate (GFR), a critical indicator of kidney function.
The remarkable precision of this new method is supported by the satisfactory analysis of not one, but two certified reference materials, solidifying its trueness. It also showed satisfactory intra- and inter-day precisions when analyzing a serum pool and control sera. Most crucially, the team’s analysis of 93 serum samples revealed negligible creatine-creatine interconversions. This finding disrupts the previously assumed correlation between creatine levels and the reliability of creatinine measurements, setting a new precedent in clinical chemistry diagnostics.
This method aligns with the Clinical and Laboratory Standards Institute (CSLI) guidelines, providing an analytical framework with adequate figures of merit for quantification of serum creatinine. With its minimally-invasive correction methodology for handling creatine-creatinine interconversion during pretreatment, it represents a significant improvement in the quality of clinical diagnostics.
The scholars’ dedication to transparency and scientific integrity is further pronounced as they uphold a clear declaration of competing interest, affirming that no known competing financial interests or personal relationships could have appeared to influence the outcomes of their work.
The authors’ effort sets a new benchmark for analytical methods in the quantification of serum creatinine and has the potential to transform kidney function assessment worldwide. Practitioners and researchers can now rely on a technique that not only advances the field of clinical chemistry but also underscores the continuous quest for accuracy and reliability in medical diagnostics.
As the implications of this study resonate across the clinical community, it stands as a testament to the power of innovation and meticulous research in overcoming longstanding challenges in medical science.
In conclusion, the University of Oviedo’s research team has made a profound contribution to clinical diagnostics with their novel reference method for quantifying serum creatinine. The negligible impact of creatine-creatine interconversion achieved with their specialized sample preparation procedure marks a new chapter in the annals of clinical chemistry.
Keywords
1. Serum Creatinine Quantification
2. Bidimensional liquid chromatography
3. Tandem mass spectrometry
4. Kidney Function Assessment
5. Analytical Chemistry Innovations
References
1. Pineda-Cevallos, D., Funes Menéndez, M., González-Gago, A., Rodríguez-González, P., & García Alonso, J.I. (2024). Correction of creatine-creatinine conversion during serum creatinine quantification by two-dimensional liquid chromatography and double-spike isotope dilution tandem mass spectrometry. Clinica chimica acta; international journal of clinical chemistry.
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