we determined the effect of long-term freezer storage and repeated thawing and freezing of serum on concentrations of electrolytes ( sodium , potassium , calcium , and phosphate ) , enzymes ( aspartate aminotransferase , alkaline phosphatase , lactate dehydrogenase , and creatine kinase ) , total protein , tumor markers ( carcinoembryonic antigen and alpha-fetoprotein ) , and other substances .
C0041365
tumor markers
C0007082
carcinoembryonic antigen