Clinical chemistry the denser blood cells and platelets to the bottom of the centrifuge tube, leaving the liquid serum fraction resting above the packed cells. This initial step before analysis has recently been included in instruments that operate on the "integrated system" principle. Plasma is in essence the same as serum, but is obtained by centrifuging the blood "without" clotting. Plasma is obtained by centrifugation "before" clotting occurs. The type of test required dictates what type of sample is used. A large medical laboratory will accept samples for up to about 700 different kinds of tests. Even the largest of laboratories rarely
Blood, toil, tears, and sweat Blood, toil, tears, and sweat The phrase "blood, toil, tears and sweat" became famous in a speech given by Winston Churchill to the House of Commons of the Parliament of the United Kingdom on 13 May 1940. This was Churchill's first speech on 13 May 1940 to the House of Commons after having been offered the King's commission the previous Friday, to become Prime Minister of the United Kingdom in the first year of World War II. Churchill had replaced Neville Chamberlain on 10 May, and in this speech he asked the House to declare its confidence in his Government.