In this study, 665 female and 650 males participated. Blood samples of the participants were used to estimate the normal value of CA 15-3 and PSA for female and male respectively. Inside you will find - Rational and important of the study. - Definition and Classification of tumor markers - Details about the method and devices used in this study. - Specimen collection and processing, storage and dilution technique. - The principle of the assay and protocol used for CA15-3. - The principle of the assay and protocol used for PSA. - Calculation of results - Recommendations to be considered shortly.