Uric Acid

1.      Uric Acid

 

Introduction

Uric acid levels are very labile and show day to day and seasonal variation in same person, also increased by emotional stress, total fasting, increased body weight, uric acid levels that do not correlate with the severity of kidney damage; urea and Creatinine are better.

Indications

Monitor chemotherapeutic treatment of neoplasms to avoid renal urate deposition with possible renal failure; monitor treatment of gout.  

 

Normal Levels
Males	Females	1 –3 years
4.0 – 8.6 mg/dL	3 – 5.9 mg/dL	1. 8 -5

Increased in

Renal failure; gout and also in 25% of relatives of patients of gout; asymptomatic hyperuricemia; leukemia, multiple myeloma, malignancies, lymphoma and other disseminated neoplasm and cancer chemotherapy; hemolytic and sickle cell anemia; toxemia of pregnancy; psoriasis (1/3 cases); drug use (barbiturates, methyl alcohol, salicylates, thiazides, furosemide, mitomycin, levodopa, phenytoin sodium); metabolic acidosis; diet (high protein, weight reduced diet). 

 

Others von Gierke's disease, lead poisoning, Down's syndrome, polycystic kidney disease, atherosclerosis and hypertension (serum uric acid is increased in 80% of patients with elevated serum triglycerides).

Decreased in

Drugs (adrenocorticotropic hormone [ ACTH], high dose salicylates, probenecid, cortisone); Wilson's disease, Fanconi's syndrome, celiac disease, xanthuria

Creatinine

Creatinine

Introduction

Serum Creatinine is the most specific and sensitive indicator of renal disease. Use of BUN and Creatinine levels together is more informative in renal disorders.

      

Normal Range
Male	Female	Fetal	Pregnancy
0.7 - 1.4 mg/dL	0.6 – 1.1 mg/dL	0.4 – 0.9 mg/dL	0.4 – 0.6 mg/dL

 

Indications

       Diagnosis of renal insufficiency

 

Increased in

Diet [ingestion of Creatinine (roast meat); prerenal azotemia; postrenal azotemia; impaired kidney function, 50% of renal function is needed to increase serum Creatinine from 1.0 – 2.0mg/dl. Therefore, not sensitive to mild – to moderate renal injury.

Decreased in

Pregnancy – normal value is 0.4 – 0.6 mg/dL. > 0.8mg/Dl is abnormal and should alert clinician to further diagnostic evaluation.

Blood Urea Nitrogen (BUN)

1.      Blood Urea Nitrogen (BUN)

 

Introduction

 

BUN correlates with uremic symptoms better than serum creatinine.

 

Normal Range

Adults: 7 –20mg/dL

Neonate: 5 –18 mg/dL

6 –8 mg/dL: associated with over hydration states

50 – 150mg/dL: implies serious impairment of renal function

150 –250mg/DL: is conclusive evidence of severely impaired glomerular function.

Indications

Differential diagnosis of various renal disorders; evidence of hemorrhage in Gl tract; assessment of patients requiring nutritional support in excess of catabolism (e.g. burns, cancer).

Increased in

Impaired kidney function; prerenal azotemia – ant case of reduced renal blood flow; congestive heart failure; salt and water depletion (vomiting, diarrhea, sweating); shock; postrenal azotemia – any obstruction of urinary tract (increased blood urea nitrogen [BUN] / Creatinine ratio); hemorrhage into Gl tract; AMI; stress.

Decreased in

Diuresis (e.g. with overhydration, often associated with low protein catabolism); severe liver damage (drug poisoning, hepatitis, other); increased utilization of protein for synthesis (late pregnancy, infancy, acromegaly, malnutrition ); diet (low protein and high carbohydrate, impaired absorption, malnutrition); nephritic syndrome; syndrome of inappropriate antidiuretic hormone secretion ( SIADH).