Each test is designed to answer specific questions. Tests from your blood may tell whether you feel tired because you have anaemia or because you have an infection… whether your chest pain means you may have heart trouble or pleurisy. Other tests also may reveal if your sore throat is caused by a streptococcal infection …. if the drug you are taking is effective… if you have infectious mononucleosis, syphilis, or leukemia. Before an operation, blood typing tells what kind of blood must be used if you need a transfusion. Tests on your urine may show if you have diabetes, if you are pregnant, if your liver or kidneys are functioning properly, or if you have bladder infection. A “Pap” smear, a scraping or cell samplings stained and studied microscopically, may disclose early signs of cervical cancer. A thin slice of body tissue mounted in a slide for microscopic examination enables your pathologist to determine whether a growth is cancerous or benign.