High Density Lipoprotein (HDL) Cholesterol (Lipid Profile)

1.      High Density Lipoprotein (HDL) Cholesterol

Introduction

Levels of HDL are inversely related to risk of CAD. For every mg/dL decreased in HDL, risk of CAD increase by 2 -3%

 

Indications

Assessment of risk of CAD

 

Diagnosis of various lipoproteinemia

 

Normal Levels
Men	Women
> 40mg/dL	> 50mg/dL

 

Increased in (60mg/Dl is negative risk factor for CAD)

 

Vigorous exercise; moderate consumption of alcohol; Increased clearance of triglyceride (VLDL), Familial lipid disorders with protection against atherosclerosis (illustrates importance of measuring HDL to evaluate hypercholesterolemia); 1 in 20 adults with mild increased total cholesterol levels (240 – 300mg/dL) secondary to increased HDL ( > 70mg/dL); Hypobetalipoproteinemia.

 

Decreased in (< 32mg/dL in men, < 38mg/dL in women)

Stress and recent illness (e.g. acute myocardial infarction [AMI], stroke, surgery, trauma); starvation, non fasting sample; obesity and lack of exercise; cigarette smoking; DM, hypo – and hyper – thyroidism; acute and chronic liver disease; genetic disorders; familial hypoalphalipoproteinemia.

Total Serum Cholesterol (Lipid Profile)

ToTotal Serum Cholesterol

Indications

Monitoring for increased risk factor for coronary artery disease(CAD); Screening for primary and secondary hyperlipidemias; Monitoring of treatment for hyperlipidemias.

 

Normal range
Adults: 130 –20mg/dL	Fetal: 32 – 76mg/dL

Increased in

Hyperlipoproteinemias; cholesteryl  ester storage disease; biliary obstruction (stone, carcinoma, cirrhosis); von Gierke's disease; hypothyroidism; nephrosis (due to chronic nephritis, amyloidosis, renal vein thrombosis, systemic lupus erythematosus [ SLE]; Pancreatic disease, diabetes mellitus.

Decreased in

Severe liver cell damage (due to chemicals, drugs, hepatitis); hyperthyroidism; malnutrition; infection and inflammation; drugs.

Oral Glucose Tolerance Test (OGTT)

Oral Glucose Tolerance Test (OGTT)

      Introduction

OGTT is done after overnight fasting for 10 –16 hrs. Certain drugs should be stopped several weeks before the test (e.g. oral diuretics, 0.Cs phenytoin). Loading dose of glucose [adults = 75gms, for children 1.75gm/kg (of ideal body weight in obese children but never > 75gms). Pregnancy = 100gms] is consumed in 5 mins. Blood sample drawn at fasting, 30, 60, 90, 120 mins.

Indications

OGTT should be reserved principally for patients with '' borderline'' fasting plasma glucose levels ( i.e. fasting range 110 – 140 mg/dL).

All pregnant women should be tested for gestational diabetes with a 50gms dose at 24 – 28 weeks of pregnancy; if result abnormal, OGTT should be performed after pregnancy.

Increased tolerance in 

Pancreatic is let cell hyperplasia or tumor, poor absorption from gastrointestinal (Gl) tract in intestinal disease (e.g. steatorrhea, sprue, colic disease), hypothyroidism Addison's disease, liver disease, hypopituitarism.

 Decreased tolerance in   

Diabetes mellitus- For diagnosis of diabetes in nonpregnant adults, at least two values of OGTT should be increased (or fasting serum glucose > 140mg/dL on more than one occasion and other causes of transient glucose intolerance must be ruled out.

                Other causes of decreased tolerance are hyperthyroidism, hyperlipidemia, steroid effect, Cushing's effect, administration of adrenocorticotropic hormone (ACTH) or steroids, pregnancy.

Drugs like indomethacin, various neuroactive drugs (phenothiazines, tricyclics, lithium, haloperidol), heparin.