BLOOD ANALYSIS 275 



affected but little. In arthritis the blood may also be high in uric acid 

 but in this case ordinarily there is a rise in non-protein nitrogen also, 

 indicating perhaps an associated nephritis in such cases. 



Lipemia is usually associated with an increased sugar content of the 

 blood. The fat content in this condition has been found as high as 29 

 per cent. There is a correspondingly large increase in the cholesterol 

 of the blood. 



In cholelithiasis there appears generally to be a fairly marked 

 increase in the cholesterol content of the blood and this determination 

 is thus of diagnostic aid. Some increase may also be found in other 

 disorders as in nephritis, severe diabetes, pregnancy, arteriosclerosis 

 and syphilis, and marked decreases have been noted in pernicious 



anemia. 1 



METHODS 



The Drawing of Blood for Analysis. A tourniquet (of soft, firm rubber 

 tubing or a strip of bandage) is drawn tightly about the arm of the patient a 

 couple of inches above the elbow. The fist is kept firmly clenched. The parts 

 about the most prominent vein (usually the median basilic) are washed with 

 alcohol, the vein is held immobile by the thumb of the operator, and a sterile 

 hypodermic needle, sharp but without too long a point, (a No. 18, an inch and a 

 half long may be used), inserted into the vein, at an angle of about 50 with the 

 surface of the arm, the opening of the needle being kept downward or to the 

 side. Blood is allowed to flow into a test tube containing about 0.02 gm. of 

 powdered potassium oxalate per 10 c.c. of tyood, the whole being immediately 

 mixed to prevent clotting. Plasma may be obtained by centrifugation. 



Blood specimens are best taken in the morning before breakfast, to 

 minimize the influence of food ingestion. Specimens should be kept 

 in the ice box and analyses preferably made on the day of withdrawal. 

 This is particularly necessary in the case of sugar, which decreases in 

 amount on standing. Denis 2 has shown, however, that at least for 

 the Folin and Wu sugar method blood may be preserved for four days 

 or more at 2o-33C., if one drop (1/30 c.c.) of commercial formalin 

 (40 per cent) solution is added to each 5 c.c. of blood. 



The Blood Analysis System of Folin and Wu 3 



By this system we may determine on a single blood nitrate the 

 following: Non-protein nitrogen, urea, uric acid, creatinine and creatine, 



1 Myers: "Practical Chemical Analysis of Blood," C. V. Mosby Co., St. Louis, 1921, 

 should be consulted for a more detailed discussion of clinical findings, references to the 

 literature, etc. 



2 Denis, W.: Jour. Biol. Chem., 44, 203, 1920. 



3 Folin and Wu: Jour. Biol. Chem., 38, 81, 1919. 



