Role of blood urea and uric acid as an aid to diagnosis:

Urea:

Urea is the end product of protein catabolism. During protein catabolism ammonia formed is converted into urea by the liver and is excreted by the kidney.

High level of blood urea :

High level of blood urea is seen in the following cases:

A. Pre renal conditions:

1. Dehydration : during vomiting and diarrhea blood urea can be increased.
2. Diabetic coma
3. Fever
4. High protein diet

B. Renal conditions:

1. Acute glomerulonephritis
2. Nephrosis
3. Malignant hypertension

C. Post renal conditions:

1. Stones in urinary tract
2. Enlarged prostate
3. Tumors of bladder

Low level of blood urea:

Urea level in blood can be decreased during pregnancy, starvation and during hepatic failure.

Uric acids:

Uric acid is end product of Purine metabolism. High level of uric acid ( hyperuricemia) is seen in the following conditions.

Hyperuricemia can be primary and secondary.

Causes for primary hyperuricemia:

1. Due to glucose 6 phosphatase deficiency ( Von Gierke’s Disease)
2. Abnormal PRPP synthesase

These causes leads high secrection of purines and ultimately their catabolism can lead to hyperuricemia.

Causes for secondary hyperuricemia:

1. Leukemias
2. Renal failure
3. Lactic acidosis