Seven routine laboratory tests for lipids: cholesterol, triglycerides, HDL cholesterol, LDL cholesterol, lipoprotein (a), ApoA1, ApoB.
1, Cholesterol (TC, CHO).
Reference values.
Appropriate level: ≤5.17mmol/L (200mg/dl).
Critical range: 5.20-5.66mmol/L (201-219mg/dl).
Elevated: ≥5.69mmol/L (220mg/dl).
Clinical significance.
Elevated.
Hazards of elevated CHO: It is likely to cause atherosclerotic cardiovascular diseases, such as coronary heart disease, myocardial infarction and stroke.
Diseases with elevated CHO: various hyperlipoproteinemia, obstructive jaundice, nephrotic syndrome, hypothyroidism, chronic renal failure, diabetes mellitus, etc.
Physiological factors that lead to elevated CHO: high-fat diet, smoking, alcohol consumption, stress, and blood concentration. May be significantly elevated in the last trimester of pregnancy and may recover after delivery.
Decrease.
Decreased CHO can be seen in various lipoprotein-deficient states, cirrhosis, malignancy, malabsorption of nutrients, and megaloblastic anemia. It can also be reduced during menstruation in women.
2. Triglycerides (TG).
Reference value.
Appropriate level: <1.69mmol/L (150mg/dl).
Critical range: 1.69~2.25mmol/L (150~200mg/dl).
Elevated: 2.26～5.63mmol/L (200～500mg/dl)
Extremely high: ≥5.64mmol/L (500mg/dl).
Clinical significance.
Elevated.
Hazards of elevated TG: Triglycerides are also a risk factor for the development of coronary heart disease and should also be given dietary control or drug therapy when they are elevated.
Common diseases with elevated TG: various hyperlipoproteinemia, diabetes mellitus, gout, obstructive jaundice, hypothyroidism, pancreatitis, etc.
Decreased.
Seen in hypolipoproteinemia, malnutrition absorption, hyperthyroidism. It can also be seen in excessive hunger, exercise, etc.
3. High-density lipoprotein cholesterol (HDL-C).
Reference value.
Appropriate level: ≥1.04mmol/L (40mg/dl).
Decreased: ≤0.91mmol/L (35mg/dl).
Clinical significance.
HDL-C is considered to be the “good cholesterol” because it transports free cholesterol accumulated in tissues to the liver, reduces cholesterol deposition in tissues, and plays an anti-atherosclerotic role. Therefore, individuals with low levels of HDL-C have an increased risk of coronary heart disease, while those with high levels are less likely to suffer from coronary heart disease.
4. Low-density lipoprotein cholesterol (LDL-C).
Reference value.
Appropriate level: ≤3.10mmol/L (120mg/dl).
Marginal elevation: 3.13-3.59mmol/L (121-139mg/dl).
Elevated: ≥3.62mmol/L (140mg/dl).
Clinical significance.
Risks of elevation.
Elevated LDL is one of the important risk factors for the development of atherosclerosis and is used to determine the presence of coronary heart disease risk and is the primary indicator for the prevention and treatment of dyslipidemia.
Elevations.
It can be seen in hereditary hyperlipoproteinemia, hypothyroidism, nephrotic syndrome, obstructive jaundice, chronic renal failure, Cushing’s syndrome, etc.
Decreased.
It can be seen in absence of β-lipoproteinemia, hyperthyroidism, digestive malabsorption, liver cirrhosis, malignancy, etc.
5. Lipoprotein(a) [Lp(a)].
Reference value: 10 to 140 mmol/L (0 to 300 mg/L).
Pathologically elevated: ≥300mg/L.
Clinical significance.
Elevated Lp(a) increases the risk of atherosclerosis and atherothrombosis, and its increased concentration is an independent risk factor for atherosclerotic cardiovascular disease.
6. apolipoprotein A1 (apoA1).
Reference value: 1.20~1.60g/L.
Clinical significance.
In general, apoAⅠ can represent HDL levels and is significantly positively correlated with HDL-C. Compared with those who are >1.60g/L, those who are <1.20g/L are more likely to suffer from coronary heart disease.
7. apolipoprotein B (apoB).
Reference value: 0.80 to 1.20g/L.
Clinical significance.
apoB mainly represents LDL levels and is significantly and positively correlated with LDL-C. Elevated apoB increases the risk of coronary heart disease, and people with >1.20g/L are more likely to develop coronary heart disease compared to those with <1.00g/L. Lowering apoB reduces the incidence of coronary heart disease and the regression of atheromatous plaques.