Lipid disorders are diagnosed with blood tests that measure the level of cholesterol and triglyceride in the blood.

Blood Tests

Cholesterol levels are checked with a blood test. A small blood sample is taken from a vein in your arm. You may need to fast for several hours, usually overnight, before your blood is taken. The test measures levels of:

  • Total cholesterol
  • LDL (bad) cholesterol
  • HDL (good) cholesterol
  • Triglycerides

The readings are interpreted as follows:

Total Cholesterol

<200 mg/dL (5.2 mmol/L)Desirable
200-239 mg/dL (5.2-6.1 mmol/L)Borderline high
240 mg/dL (6.2 mmol/L) and aboveHigh

LDL Cholesterol

less than 100 mg/dL (2.6 mmol/L)Optimal
100-129 mg/dL (2.6-3.3 mmol/L)Near optimal/above optimal
130-159 mg/dL (3.4-4.0 mmol/L)Borderline high
160-189 mg/dL (4.1-4.8 mmol/L)High
>190 mg/dL (4.9 mmol/L) and aboveVery high

HDL Cholesterol

60 mg/dL (1.6 mmol/L) and aboveProtective against heart disease
less than 40 mg/dL (1.0 mmol/L)A major heart disease risk factor


less than 150 mg/dL (1.7 mmol/L)Normal
150-199 mg/dL (1.7-2.2 mmol/L)Borderline high
200-499 mg/dL (2.3-5.6 mmol/L)High
500 mg/dL (5.7 mmol/L) and aboveVery high

mg/dL = milligrams per deciliter of blood (mmol/L= millimoles per liter of blood)