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). 

Triglycerides (80% in VLDL 15% in LDL)

1.      Triglycerides (80% in VLDL 15% in LDL)

Introduction

Triglyceride levels are not strong predictors of atherosclerosis or CAD and may not be an independent risk factor. Triglyceride levels are inversely related to HDL cholesterol levels.

Normal Range
20 –170mg/dL
Classification
Normal Range	Borderline	High	Very high
< 150mg/dL	150 – 199mg/dL	200 – 499mg/dL	> 500mg/dL

 

Increased in

Genetic hyperlipidemias (e.g. Lipoprotein lipase deficiency, apo C..II deficiency, familial Triglyceridemia, dysbetalipoproteinemia); secondary hyperlipidemias (gout, pancreatitis, acute illness (e.g. in AMI rises to peak in 3 weeks and increase may persist for 1 year); drug use (e.g. thiazides, steroids, amiodarone, interferon).

Decreased in

Abetalipoproteinemia; malnutrition; vigorous exercise; drugs (e.g. ascorbic acid, clofibrate, phenformin, metformin, progestins).  

LDL (Low Density Lipoprotein) cholesterol (Lipid Profile)

1.      LDL (Low Density Lipoprotein) cholesterol

Introduction

LDL levels are directly related to risk fill CAD

 

Indication

Assess risk and decide treatment for CAD

 

Normal Levels

 

      No coronary heart disease (CHD) and < 2 risk factors < 160mg/dL

 

No CHD but > 2 risk factors < 130mg/dL

 

Presence of CHD < 100mg/dL

Increased in

Familial hypercholesterolemia and combined hyperlipidemia; diabetes mellitus (DM) and hypothyroidism; chronic renal failure; diet high in cholesterol and total and saturated fat;

Pregnancy; cholesteryl ester storage disease; drug use (e.g. anabolic, steroids, beta – blockers, progestins, carbamazepine).

Decreased in

Severe illness; abetalipoproteinemia; some laboratories also various ratios; total cholestero/HDL ratio – low risk: 3.3 – 4.4, average risk: 4.4 – 7.1, moderate risk: 7.1 – 11.0, high risk > 11.0.