Background: An incomplete separation of disialotransferrin (CDT) and trisialotransferrin (a non-CDT isoform) may cause false-positive CDT results in alcohol abuse testing. We describe a currently unknown disialotransferrin-trisialotransferrin-bridging phenomenon (di-tri-bridge) appearing with high prevalence in serum from liver cirrhosis patients.
Methods: Twenty one consecutive serum samples with a di-tri-bridge encountered in routine CDT HPLC (Clin-Rep(R)-CDT-on-line, Recipe) were investigated by a candidate reference CDT HPLC method, by capillary electrophoresis (Capillarys-CDT, Sebia) and by transferrin genotyping. Patients clinical background was assessed by telephone interview.
Results: Out of 21 consecutive serum samples showing a di-tri-bridge (and increased trisialotransferrin fractions) in HPLC as well as in CE analysis, 19 were from patients with a liver cirrhosis history. Genotyping (where applicable by the availability of DNA: n=12) yielded most frequently homozygous transferrin C1 (6x), proving that the di-tri-bridge cannot be explained by genetic transferrin variants in these samples. Other genotypes found were C2 (1x), C1C2 (4x), C1C3 (1x).
Conclusion: The frequently seen di-tri-bridging phenomenon in transferrin HPLC analysis for patients with liver cirrhosis is not explained by genetic transferrin variants or by an increased trisialotransferrin fraction. Although further studies are needed to assess the relationship between this phenomenon and liver cirrhosis, our observation could be helpful in development of a biomarker for liver cirrhosis.