Apolipoprotein B test

[JacquelineL]

I am getting confused with the A and B lipids. My doctor ordered this test for my husband along with hs C-Reactive Protein and Homocysteine. The last two we wanted but we also suggested a lipoprotein(a) test. He added that to the list. What is the Apolipoprotein B test? I did a search and found that it measures Apo B-100 which can be a cardiac risk. I though that lipoprotein(a) was the bad one and in an A/B ratio, it was good to be toward pattern A. I hope someone can make this clear.

[ARIZONA73]

Jacqueline,

All I know about apolipoprotein A & B is that they are carrier molecules for cholesterol. The Apo B is the carrier molecule for LDL, and the Apo A is the carrier molecule for the HDL. At least, that's my understanding of it. Lipoprotein(a) is something else. It's a plasma protein with a structure and composition that closely resembles those of LDL, but with an additional molecule of an adhesive protein. Perhaps someone else can contribute some additional information about this.

[CobaltBlue]

Originally Posted by JacquelineL

I am getting confused with the A and B lipids. My doctor ordered this test for my husband along with hs C-Reactive Protein and Homocysteine. The last two we wanted but we also suggested a lipoprotein(a) test. He added that to the list. What is the Apolipoprotein B test? I did a search and found that it measures Apo B-100 which can be a cardiac risk. I though that lipoprotein(a) was the bad one and in an A/B ratio, it was good to be toward pattern A. I hope someone can make this clear.

Arizona did a great job of explaining it. It depends on how deep you really want to go, but basically, think of Apo A (mainly Apo A-I) as an alternative measure to HDL and Apo B-100 as an alternative to LDL. Really though, the Apo B-100 also is a primary protein component of VLDL, which are your triglyceride carriers. There are breakdown percentages of these Apolipoproteins for HDL, LDL, and VLDL, and if you really want to know them I can post them. To be honest, its probably just to leave it as the relationships Arizona described.

Now, Lp(a) is made in the liver, and its similar to LDL (Apo B-100 is the primary protein and its linked by a -S-S- bridge to Apo(a)).

OK now back to your A/B pattern types. Are you sure in this case that your physician wasn't referring to particle sizes as type A and type B? In that case, A and B aren't related to the Apo-A and Apo-B described above. It sounds like your husband is having an NMR lipoprofile analysis and in that case you will get information on the particle sizes (type A, which is low risk particle size 20.6-22 vs. B, higher risk, <20.6 nm) and still get the LDL, HDL and VLDL concentrations in the plasma. The additional tests that can be ordered are hs-CRP, homocysteine, and Lp(a), as you mentioned in your post.

I have an some results from NMR lipoprofiles in a post made a while ago (sorry about the columns not lining up well anymore, but the lipoprofiles are in the 2nd post):
[url]http://www.healthboards.com/boards/showthread.php?t=61608[/url]

[JacquelineL]

Thanks to both of you for the great explanations. I will have to mull them over for a while. Maybe more than I wanted to know, but it is becoming clearer.

[JacquelineL]

Ubernier

I've been looking at your lipoprofile and trying to associate the results I got on my recent VAP test. There were a lot of subclasses on the second page of it that didn't mean much to me. Maybe you can make sense of them.

Dense HDL 3d 10.9, 3c 12.0, 3b 5.8, 3a 14 Total 43 (less protective)

Buoyant HDL 2a 8.2, 2b 1.2, 2c 2.3 Total 12 (more protective)

Lp(a)4 9.3 Lp(a)1 4.4 The other 3 subclasses were 0. Total Lp(a)=14

Real LDL LDL4 14.3 LDL3 45.3 These 2 represent pattern B (bad)

LDL2 21.8 LDL1 8.1 pattern A (good)

IDL2 4.4 IDL1 2.5

VLDL 3b 2.2 VLDL 3b 1.6 VLDL 1+2 3.5

Apoprotein B-100 ias located in each of these subclass particles- LDL, Lp(a), IDL, and VLDL in a ratio of one Apoprotein B-100 molecule per particle.