Allen's test assess for circulation to hand via both ulnar and radial arteries. Pt squeezes hand in fist for 30 seconds. occlude both arteries with fingers, pt opens hand (should be blanched).  release arteries, color should return in <7 seconds (positive) If negative, arteries are not patent, don't poke! specific gravity of urine the ratio of density of urine to density of water water =1.000 SG = 1.002-1.03 normal phosphorous level 2.5-4.5 Central Venous Pressure (CVP) direct measurement of the blood pressure in the right atrium and vena cava Normal =4-11 cm H20