Davis's Lab & Diagnostic Tests
Cholesterol, Total and Fractions
General
Core Lab Study
Synonym/Acronym:
alpha1-Lipoprotein cholesterol, high-density lipoprotein cholesterol (HDLC); and beta-lipoprotein cholesterol, low-density lipoprotein cholesterol (LDLC), very-low-density lipoprotein (VLDL); lipid fractionation; lipoprotein phenotyping.
Rationale
To assess and monitor risk for coronary artery disease (CAD).
A small group of studies in this manual have been identified as Core Lab Studies. The designation is meant to assist the reader in sorting the basic “always need to know” laboratory studies from the hundreds of other valuable studies found in the manual—a way to begin putting it all together.
Normal, abnormal, or various combinations of core lab study results can indicate that all is well, reveal a problem that requires further investigation with additional testing, signal a positive response to treatment, or suggest that the health status is as expected for the associated situation and time frame.
Cholesterol is the study most commonly used to screen and assess risk for atherosclerotic cardiovascular disease. Cholesterol is included in the lipid panel.
Patient Preparation
There are no medication restrictions unless by medical direction. Instruct the patient to fast 6 to 12 hr before specimen collection if lipoprotein fractionation or triglyceride measurements are ordered and recommend fasting if cholesterol levels alone are measured for screening. Instruct the patient to avoid excessive exercise for at least 12 hr before lipoprotein fractionation testing and to refrain from alcohol consumption for 24 hr before lipoprotein fractionation testing. Protocols may vary among facilities.
Normal Findings
Method: Spectrophotometry for total cholesterol, HDLC and LDLC. Lipoprotein fractionation: Electrophoresis and 4°C test for specimen appearance. There is no quantitative interpretation of this test. The specimen appearance and electrophoretic pattern are visually interpreted.
| Total Cholesterol | ||
|---|---|---|
| Age and Risk Stratification | Conventional Units | SI Units (Conventional Units × 0.0259) |
| Children and adolescents (less than 20 yr) | ||
| Desirable | Less than 170 mg/dL | Less than 4.4 mmol/L |
| Borderline | 170–199 mg/dL | 4.4–5.2 mmol/L |
| High | Greater than 200 mg/dL | Greater than 5.2 mmol/L |
| Adults and older adults | ||
| Desirable | Less than 200 mg/dL | Less than 5.2 mmol/L |
| Borderline | 200–239 mg/dL | 5.2–6.2 mmol/L |
| High | Greater than 240 mg/dL | Greater than 6.2 mmol/L |
| HDLC (Acceptable Guidelines by Age) | Conventional Units | SI Units (Conventional Units × 0.0259) |
|---|---|---|
| Birth | 6–56 mg/dL | 0.16–1.45 mmol/L |
| Age 2 yr–17 yr | Greater than 45 mg/dL | Greater than 1.17 mmol/L |
| 18 yr–Adults and older adults | ||
| Male | Greater than or equal to 40 mg/dL | Greater than or equal to 1 mmol/L |
| Female | Greater than or equal to 50 mg/dL | Greater than or equal to 1.3 mmol/L |
| LDLC (Acceptable Guidelines by Age) | Conventional Units | SI Units (Conventional Units × 0.0259) |
|---|---|---|
| Age 2 yr–17 yr | Less than 110 mg/dL | Less than 2.8 mmol/L |
| Adults and older adults | Less than 100 mg/dL | 2.59 mmol/L |
| Hyperlipoproteinemia: Fredrickson Type | Specimen Appearance | Electrophoretic Pattern |
|---|---|---|
| Type I | Clear with creamy top layer | Heavy chylomicron band |
| Type IIa | Clear | Heavy beta band |
| Type IIb | Clear or faintly turbid | Heavy beta and pre-beta bands |
| Type III | Slightly to moderately turbid | Heavy beta band |
| Type IV | Slightly to moderately turbid | Heavy pre-beta band |
| Type V | Slightly to moderately turbid with creamy top layer | Intense chylomicron band and heavy beta and pre-beta bands |
Critical Findings and Potential Interventions
N/A
There's more to see -- the rest of this topic is available only to subscribers.
