Viral Load Lab Problems

[tednlou2]

I went to the HIV doc the other day for a problem going on with my mouth.  I would like to ask you guys about that issue and possibly show a pic, but I don't want to put too many issues into one post.  Maybe I'll create a separate post for that.

Anyway, while waiting in the room, I could hear the lab director updating my doc on an issue with viral load testing which he said was also affecting genotype testing.  I asked my doc about what I heard.  They have noticed patients who get their viral load testing done at the university lab (where the HIV clinic is) often have viral loads that jump up from undetectable--some just a few points, but some much higher.  This is in stark contrast to patients who get their labs done at Labcorp--even the same patients who were detectable under their lab but UD under Labcorp's lab.  The lab guy said this may be due to initial freezing of the specimens that are sent to a lab in Atlanta.  He also talked about using "the white tubes vs the purple tubes."  I still don't know what that means. 

My doc said this not only causes psychological stress to patients, but could prevent them from participating in studies where you have to be UD.  The bottom line is that they believe the lab at the HIV clinic is many times causing viral loads to be higher than they actually are and they also said this issue or series of issues is/can affect genotype assays.  I asked whether my viral load could actually be lower than it is saying.  Doc said possibly, but this problem is mainly an issue for those on meds with UD viral loads that are bouncing around.  I should have asked whether they believe this problem has caused any to switch regimens thinking it wasn't working.  They are now starting a study of patients at random to prove their hypothesis.  It is good they have discovered the problem and are taking action to remedy it. 

I just thought this was interesting and made me think about the stories we hear where people say they are completely adherent but either can't get all the way undetectable or it will bounce back up.

Update:

I mentioned this to Dr. Gallant in a post to him from someone who says he is 100% adherent, but his/her vl jumps to 500.  Below is what he said about what I just wrote to you guys.

On Aug 20, 2010 Joel E. Gallant, M.D., M.P.H. replied:

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There was a problem several years ago with incorrect processing of viral load specimens, which resulted in falsely elevated results. The problem was that labs were centrifugin plasma preparation tubes (PPT) and then freezing them without first separating the plasma from the cells. It was believed that virus from the cellular component somehow made its way into the plasma and got counted as plasma virus.

The correct way to process a viral load sample is either with a PPT tube or an EDTA tube, where you first centrifuge the tube, and then remove the plasma before freezing it. This has been known now for several years, and all the labs I know have switched to this method. If a lab is still doing it the wrong way, that's concerning.

The full Q&A:  http://www.hopkins-hivguide.org//q_a/patient/recent_questions/worried_guy_continued.html?contentInstanceId=533469&siteId=7151   

[Granny60]

I do believe that the way labs handle the samples or analyze them can make a difference.  Hubby had to change to LabCorp from Quest because his thieving insurance company refused to pay Quest and we had $30 some thousand in outstanding bills from them.  The LabCorp tests were a disaster!  His testosterone was all over the place bouncing up and down  by 300 points,   Cd4 would go down then up , then down,  They would call and tell  him  to come back in  ( as many as 3 times)  stating they were unable to get the CD4 or viral load. Sometimes they would call to come back because they said they lost the results. We know another person that this has happened to also. Thankfully we got the insurance issue taken care of and he gets to go to a reliable lab again. We don't need any more WTF?  in our lives.

[Miss Philicia]

I've used both LabCorps and Quest and never had any issue.