Reports and White Papers

Articles, reports and commentaries containing useful and revelant information about Gentian Cystatin C immunoassay and its clinical usage.

Gentian cystatin C immunoassay is best in test with turbid serum samples

Presented at the European Biomarkers Summit, Barcelona November 5-6, 2009.

The study, carried out at Buskerud Hospital in Drammen, Norway and Länssjukhuset Halmstad, Sweden, shows that Roche Tina-quant, Dako and Diazyme cystatin C immunoassay measurements are significantly affected by the presence of turbidity in serum samples. Turbidity interference results in a significant over-estimation or under-estimation of serum cystatin C depending on the type of assay. There is an even higher over-estimation or under-estimation of GFR. For Roche, Diazyme and Dako cystatin C assays respectively, the over-estimation or under-estimation of cystatin C can be as high as 25%, 50% and 10%. When these figures are used to calculate GFR then the over-estimation or under-estimation of GFR can be as high as, respectively, 60%, 70% and 18%.

Early Detection of even mildly reduced GFR is important. Identifying early renal insufficiency has become increasingly important as the number of patients with renal failure is growing worldwide. Newer research indicates that mild kidney failure can be reversed with early identification and correct treatment. Therefore, a 20% over-estimation of GFR value may have a severe impact on patient treatment.

Roche, Diazyme and Dako cystatin C immunoassays show significant deviations from expected values due to interference from turbidity.

Gentian cystatin C immunoassay is insignificantly affected by turbidity in serum samples. The effect of turbidity does exist but is within an acceptable range for Gentian reagents.

Click here to download the Gentian vs. Roche, Diazyme and Dako turbidity poster presentation.

TG interference study confirms Gentian cystatin C immunoassay is superior to Roche Diagnostics cystatin C immunoassay

This poster was presented at the Spring Meeting for the Swedish Society for Clinical Chemistry (SFKK) May 14, 2009.

The study, carried out at Länssjukhuset Halmstad Sweden, shows that the Gentian cystatin C immunoassay is little affected by the presence of triglycerides in serum samples compared with Roches Tina-quant cystatin C immunoassay. Patients with high TG due to obesity or other medical conditions are susceptible to renal insufficiency. TG interference results in an under-estimation of serum cystatin C measurement of up to 20% with the Roche cystatin C immunoassay. As a result, the GFR levels calculated using the Roche cystatin C immunoassay may have an overestimation of up to 20% (mean). If TG levels exceed 10mmol/L overestimation of GFR can be as high as 50%.

There is a significant difference between the Gentian and Roche cystatin C immunoassays.

Click here to download the Gentian vs. Roche TG interference poster presentation.

Standardization of Gentian Cystatin C calibrator against IFCC Cystatin C standard.

The IFCC cystatin C standard won’t be available for 1-2 years, but the Gentian Cystatin C calibrator already meets that standard. Click here to view the report about conformity between the Gentian's calibrator and world standard calibrator.

Ring Study of Gentian Cystatin C

In this study, 13 series of measurements on 8 different analyser platforms at 8 different sites are compared over a period of 3 years.

The results show excellent inter-laboratory and cross platform precision. Since the study covers a period of three years, the results also indicate that there is little variation between production batches of the Gentian reagents. Click here to view the Ring Study report.

Commentry on an analytical study of three cystatin C assays

In his article "Analytical study of three cystatin C assays and their impact on cystatin C-based GFR-prediction equations"., Delanaye compares Gentian cystatin C immunoassay with the Dade-Behring and Dako methods.

Delanaye's results suggest that the Gentian cystatin C immunoassay is the preferred method for measuring cystatin C. Click here to view the Commentry on an analytical study of three cystatin C assays.