Cholesterol or lipid profile

Mini-Case*: Patient - My cholesterol is 295.... Don't remember what type of cholesterol. Aren't they all the same?

Thinking: Cholesterol values include Total cholesterol, LDL, HDL, VLDL, which one? What is what?
=> Conclusion: most likely to be 'Total cholesterol' if pt only can only report 1 # but not any other #'s.


Case*: Pt is 50y/o with diabetes. Which Cholesterol level to start on Simvastatin?
Answer: Cholesterol level doesn't matter. No need to obtain lipid panel test. Just start them on Simvastatin.

Case*:  Pt asks How does Simvastatin affect HDL and LDL?
Answer: Lower LDL but very miniscule effects on HDL

Why it works?

Blurb:

Total cholesterol

LDL (bad) cholesterol--the main source of cholesterol buildup and blockage in the arteries

HDL (good) cholesterol--helps keep cholesterol from building up in the arteries

Triglycerides--another form of fat in your blood

What is total cholesterol?

Total Cholesterol (done by enzymes, measured directly from blood):  Total cholesterol can be measured directly from blood. Enzyme (cholesterol oxidase) is added to produce reaction byproducts, H2O2.  Enzyme (Peroxidase) is then added to produce color. This color is electromagnetically analyzed at 500nm. The intensity of this color is directly proportional to cholesterol concentration.

Triglycerides (done by enzymes, measured directly from blood) - must be fasting for correct level of triglycerides

HDL (done by special agents, measured directly from blood, read by color intensity produced from electromagnet)

LDL: very expensive to measure directly from blood via ultra-centrifuge. So, use Friedwald equation (only correct if pt is fasting)

LDL-Cholesterol: Most of the circulating cholesterol is found in three major lipoprotein fractions: very low density lipoproteins (VLDL), LDL and HDL.

[Total chol] = [VLDL-chol] + [LDL-chol] + [HDL-chol]

LDL-cholesterol is calculated from measured values of total cholesterol, triglycerides and HDL cholesterol according to the relationship: 

                          [LDL-chol] = [total chol] - [HDL-chol] - [TG]/5

 where [TG]/5 is an estimate of VLDL-cholesterol and all values are expressed in mg/dL. 

~Miss Student

*All cases are fictitious. No real patient encounters. Just my rich imagination! :)


Read lab values:
Mnemonics: High Healthy HDL; Low Let it down LDL ~Miss Student

Nutrition:

Diet restrictions: 
1 - No Alcohol 24hrs before tests (elevate #)
2 - No eating 12 hrs before tests (elevate triglycerides)
3 - No water restrictions

Clinical procedure:
- Blood lab test (venipuncture)
- Red tube (fasting)

Who should be screened?:
In priority order:

1. - All men over 35 y/o even in absence of any risk factors for CHD
2. - Men & women >20 y/o with increased risks for coronary heart disease (CHD)

Increased risk, for the purposes of this recommendation, is defined by the presence of any one of the risk factors listed below. The greatest risk for CHD is conferred by a combination of multiple listed factors.

• Diabetes.

• Previous personal history of CHD or non-coronary atherosclerosis (e.g., abdominal aortic aneurysm, peripheral artery disease, carotid artery stenosis).

• A family history of cardiovascular disease before age 50 in male relatives or age 60 in female relatives.

• Tobacco use.

• Hypertension.

• Obesity (BMI ≥30).

10-year CVD risk factors: http://cvdrisk.nhlbi.nih.gov/

Helpful link:
http://www.gpnotebook.co.uk/simplepage.cfm?ID=x20030114211535665170: short need-to-know details for lipid profile info.
(2) http://www.cdc.gov/nchs/data/nhanes/nhanes_03_04/l13_c_met_lipids.pdf: how to calculate total cholesterol => not how total cholesterol is usu. obtained since you can do measure total cholesterol by hands
http://www.wikihow.com/Calculate-Total-Cholesterol => how lipid panel is really measured
http://www.uspreventiveservicestaskforce.org/Page/Document/RecommendationStatementFinal/lipid-disorders-in-adults-cholesterol-dyslipidemia-screening#consider