Doctors can figure out certain types of unhealthy blood fat levels—like type IIb or IV—by checking your apoB, cholesterol, and triglycerides, without needing fancy or rare tests.

ApoB is a better blood test for predicting heart disease than standard cholesterol tests because it counts the actual particles that clog arteries, while cholesterol numbers can be misleading since each particle carries different amounts of cholesterol from person to person.

Measuring apoB might give a better picture of heart disease risk than LDL cholesterol because it counts the actual number of harmful particles in your blood, not just how much cholesterol they carry.

Measuring a protein called apoB in the blood is super accurate and consistent — more so than a common cholesterol test — so it could be a great option for regular check-ups.

In a rare blood fat disorder called type III hyperlipoproteinemia, heart disease risk comes from leftover fat particles in the blood — not from the usual risk marker. Even if your 'bad particle' count looks okay, these leftovers can still clog arteries, so doctors can't rely on that usual test here.

The amount of cholesterol in each 'bad' particle in your blood can change because of a protein called CETP, which means counting cholesterol might not give the full picture of heart disease risk.