Reference levels of the tumor markers carcinoembryonic antigen, the carbohydrate antigens 19-9 and 72-4, and cytokeratin fragment 19 using the Elecsys Relecsys 1010 analyzer in a normal population in Kuwait. The importance of the determination of local reference levels

Int J Biol Markers. Jan-Mar 2002;17(1):67-70. doi: 10.5301/jbm.2008.414.


The tumor markers CEA, CA 19-9, CA 72-4 and CYFRA 21-1 were analyzed in a group of apparently healthy subjects (n=232) in Kuwait using the Elecsys Relecsys 1010 analyzer. The distribution of the tumour marker levels was analyzed separately in Kuwaitis (n=103), non-Kuwaitis (n=129), smokers (n=68), non-smokers (n=164), males (n=138) and females (n=94). The distribution of CEA was significantly different in Kuwaitis vs. non-Kuwaitis in the total population (p=0.033) and in non-smokers (p=0.049); in males vs. females in the total population (p<0.0001) and in non-smokers (p=0.0002); and in smokers vs. non-smokers in the total population (p<0.0001) using the non-parametric Mann-Whitney U test. None of the other tumour markers showed significant differences in the subgroups. The upper reference level was defined as the 95th percentile of the normal values in each group. A higher reference level of CEA was observed in smokers (vs. non-smokers) in the total population. Also higher reference levels of CEA were observed in males (vs. females) both in the total population and in non-smokers. In the total population the respective reference levels were: CEA: 4.4 microg/L, CA 19-9: 35 kU/L, CA 72.4: 2.4 kU/L, and CYFRA 21.1: 2.1 microg/L. These results were compared with data in the kit inserts and literature data. The impact of 95th percentiles in a local heterogeneous population is discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age Factors
  • Antigens, Tumor-Associated, Carbohydrate / biosynthesis*
  • Biomarkers, Tumor
  • CA-19-9 Antigen / biosynthesis
  • Carcinoembryonic Antigen / blood*
  • Female
  • Humans
  • Keratins / biosynthesis
  • Kuwait
  • Male
  • Middle Aged
  • Reference Values
  • Smoking


  • Antigens, Tumor-Associated, Carbohydrate
  • Biomarkers, Tumor
  • CA-19-9 Antigen
  • CA-72-4 antigen
  • Carcinoembryonic Antigen
  • Keratins