Non-protein Nitrogen (NBN) 285 PHL

Non-protein Nitrogen Major components of the NPN Urea, uric acid, creatinine, creatine, amino acids & ammonia Importance: Test for kidney function NPN is now replaced by determination of blood urea nitrogen (BUN) because: 1- Urea constitutes 45% of NPN 2- Urea is excreted by glomerular filtration and partially reabsorbed through renal tubules Major components of the NPN Urea, uric acid, creatinine, creatine, amino acids & ammonia Importance: Test for kidney function NPN is now replaced by determination of blood urea nitrogen (BUN) because: 1- Urea constitutes 45% of NPN 2- Urea is excreted by glomerular filtration and partially reabsorbed through renal tubules

Urea Urea is the end product of protein and nucleic acids metabolism - It is synthesized in liver from CO 2 & NH 3 Urea is the end product of protein and nucleic acids metabolism - It is synthesized in liver from CO 2 & NH 3

Urea Normal value 10 – 50 mg/dl Clinical significance ↑ BUN (Hyperuremia) 1-Pre-renal causes - ↓ Renal blood flow (e.g. CHF & dehydration) - ↑Protein catabolism (as in fever) - High protein diet - Corticosteroid drugs Normal value 10 – 50 mg/dl Clinical significance ↑ BUN (Hyperuremia) 1-Pre-renal causes - ↓ Renal blood flow (e.g. CHF & dehydration) - ↑Protein catabolism (as in fever) - High protein diet - Corticosteroid drugs

Urea: Clinical significance 2-Renal causes - Acute and chronic renal failure - Glomerular nephritis - Tubular necrosis - Malignant hypertension 3- Post- Renal causes - Urethral stones - Tumors of bladder - Prostate enlargement 2-Renal causes - Acute and chronic renal failure - Glomerular nephritis - Tubular necrosis - Malignant hypertension 3- Post- Renal causes - Urethral stones - Tumors of bladder - Prostate enlargement

Urea: Clinical significance ↓ BUN (hypouremia) Could be due to: -Liver failure -Malnutrition -Overhydration -Early stages of pregnancy -Low protein diet ↓ BUN (hypouremia) Could be due to: -Liver failure -Malnutrition -Overhydration -Early stages of pregnancy -Low protein diet

Uric acid Uric acid is the final breakdown product of purine metabolism Normal value Men : mg/dl Women: 2 -5 mg/dl Uric acid is the final breakdown product of purine metabolism Normal value Men : mg/dl Women: 2 -5 mg/dl

Uric acid Disease correlations ↑ uric acid (Hyperuricemia) Gout Pregnancy toxemia Chemotherapy Chronic renal disease Disease correlations ↑ uric acid (Hyperuricemia) Gout Pregnancy toxemia Chemotherapy Chronic renal disease

Uric acid ↓uric acid (Hypourecimia) Liver disease Fanconi’s syndrome ( defective tubular reabsorption disorder) Uricosuric drugs e.g. salicylate ↓uric acid (Hypourecimia) Liver disease Fanconi’s syndrome ( defective tubular reabsorption disorder) Uricosuric drugs e.g. salicylate

Creatinine Creatinine is the internal anhydride derived from dephosphorylation of creatine phosphate Creatinine is the internal anhydride derived from dephosphorylation of creatine phosphate

Creatinine Normal value Male: mg/dl Female: 0.6 – 1.13 mg/dl Clinical significance ↑ level of creatinine indicates abnormal renal function Normal value Male: mg/dl Female: 0.6 – 1.13 mg/dl Clinical significance ↑ level of creatinine indicates abnormal renal function