Aa
A
A
Close
Blank
1669790 tn?1333666195
<43 IU/mL, but detectable - I think I finally get it
In a recent post there was a report of "Detectable <43 IU/mL".  It didn't make sense to me since I was familiar with Quest's Hepatitis C Viral RNA, Quantitative Real-Time PCR with 43 IU/mL as the lowest detection limits.  However, after reading the following from Labcorp's test, this might help to explain why it listed <43, but detectable.  

Labcorp's Hepatitis C Virus (HCV), Quantitative, RNA PCR (Nongraphical) With Reflex to Genotyping reads as follows:
- "The limit of detection of this assay is 7.1 IU/mL for HCV genotype 1, and the quantifiable range of the assay is 43 IU/mL to 69,000,000 IU/mL."  So, this test and possibly others can detect above 7.1 IU/mL and under 43 IU/mL that virus is present, but cannot quantify or count the virus under the quantifiable range of 43 IU/mL.    

https://www.labcorp.com/wps/portal/!ut/p/c0/04_SB8K8xLLM9MSSzPy8xBz9CP3I1JT8YquyzNTykNTiEqdKEOlXmpuUWqQfDlJeguBHmpoaGFga6Bfk5joCAIx2trw!/

Sorry for the hair splitting and to those that already understood, but I hope it helps some others to understand these confusing  reports.  And if I got this all wrong, please let me know.  This stuff is still so new to me.    

Cancel
16 Answers
16 Answers
Page 1 of 1
1747881 tn?1358189534
Your not alone, I didn't get it either, lynda almost had to smack over the head before I understood.
Comment
Cancel
1747881 tn?1358189534
Comment
Comment
Submit Comment
Avatar universal

Sometimes takes a while...:0        good tho you guys are interested enough to keep at it

Heck...I still don"t know how to use my  black berry and been trying for 4 years  :)
Comment
Cancel
Avatar universal
Comment
Comment
Submit Comment
1748829 tn?1338040641
I'm confused
Comment
Cancel
1748829 tn?1338040641
Comment
Comment
Submit Comment
190885 tn?1333029491
mine was 43 at 4 weeks...they said it was almost none...i still don't get it all the way...i have to wonder how long they'll want me to tx...in 2 weeks i'll know my 8 week and would like to think i'll be undetectable.....thanks for looking into this......billy
Comment
Cancel
190885 tn?1333029491
Comment
Comment
Submit Comment
Avatar universal
Regarding the Labcorp test flcyclist is talking about:

The limit of quantitation on that test is 43 IU/mL or above.  If HCV RNA is deteced the test can give a numeric number (viral load) if the IU/mL is 43 or above.  The level of dectection goes down to 7.1 IU/mL.  The assay will detect HCV RNA down to 7.1 IU/mL which is fairly sensitive but it can't quantify or give a numeric value for any HCV RNA detected between 7.1 IU/mL and 42 IU/mL.  The patient is still detected, but no numeric value can be assigned.  
HCV RNA detected but under the quatifiable range should not be considered undetected.  This is particually important for patients treating with Incivek at the 4 week mark.
Comment
Cancel
Avatar universal
Comment
Comment
Submit Comment
1669790 tn?1333666195
After reading the Labcorp test, for some reason it suddenly became very clear.  I reread your response in dixiechic's thread and it says essentially the same thing, but I guess my mind wasn't digesting quickly enough.  Thanks for your help in clarifying.  

I just didn't want to hijack dixie's great news with this technical stuff.
Comment
Cancel
1669790 tn?1333666195
Comment
Comment
Submit Comment
789911 tn?1368640383
does anyone have an example of what a test result for the quests HCV RNA Quant RT PCR <43 looks like for detectable or undetectable <43 looks like. also for the lab corp test you are talking about here?  Thanks  Lydia
Comment
Cancel
789911 tn?1368640383
Comment
Comment
Submit Comment
Avatar universal
The test will read either:

<43 HCV RNA DETECTED
                 or
<43 HCV RNA NOT DETECTED

This is with the LabCorp Hepatitis C Virus (HCV), Quantitative, Real-time PCR

If HCV RNA detected at 43 IU/mL or above the test will give the numeric value.  
Comment
Cancel
Avatar universal
Comment
Comment
Submit Comment
Avatar universal
Sorry his3707, you were inquiring about the Quest RT PCR.  I did not see the "quest" until after I had posted the above.
Comment
Cancel
Avatar universal
Comment
Comment
Submit Comment
1669790 tn?1333666195
My understanding of Quest's HCV RNA Quant RT-PCR is if detectable, it will need to be above the lower detection limits of 43 IU/mL.   If the results read < 43 IU/mL, then it is und.  It won't report und on the results.  The Linear range of the test is: 43 to 69,000,000 IU/mL.

It you do Quest's more sensitive TMA test, Hepatitis C Viral RNA, Quantitative TMA, the lower detection limits is 5 IU/mL.  The Linear range of this test is: 5 to 7,500 IU/mL.  

This is why I was confused since Quest doesn't appear to have a test such as Labcorp's that can detect below the lower limits, but doesn't doesn't quantify the results.  If I understand correctly, Quest's tests don't report this way.  

The Heptimax test combines these two test as a rollover, so if you're interested in just doing the TMA, you can do that to save time and money.  

http://www.questdiagnostics.com/hcp/intguide/jsp/showintguidepage.jsp?fn=TS_HCV_RNA_QuantPCR.htm

http://www.questdiagnostics.com/hcp/intguide/jsp/showintguidepage.jsp?fn=TS_HCV_RNA_QuantTMA.htm

http://www.questdiagnostics.com/hcp/intguide/jsp/showintguidepage.jsp?fn=TS_Heptimax.htm
Comment
Cancel
1669790 tn?1333666195
Comment
Comment
Submit Comment
1654058 tn?1407162666
I get it now. It scares the crap out of me as I approach week 8 tho. So much is riding on this!
I just went in for a cbc differential at the local university lab so they could fax it to my hospital in OKC. I cried n hugged the nurses just talking about 4 week und.
Thanks once again for appealing to our logic. We gotta keep our wits about us while we're still fighting..
Karen :)
Comment
Cancel
1654058 tn?1407162666
Comment
Comment
Submit Comment
Avatar universal
"My understanding of Quest's HCV RNA Quant RT-PCR is if detectable, it will need to be above the lower detection limits of 43 IU/mL.   If the results read < 43 IU/mL, then it is und."

Actual results have read:

"HCV RESULTS (IU) IU/mL
HCV RNA Detected, less than 43 IU/mL.            
HCV RESULT (LOG)   <1.63     Log 10"

And

"HCV RESULTS (IU)  IU/mL
HCV RNA Not detected.                            
HCV COMMENT  The lower limit of quantitation is 43 IU/mL."

My clinic accepts "Detected, less than 43 IU/ml" as detected.
Comment
Cancel
Avatar universal
Comment
Comment
Submit Comment
1669790 tn?1333666195
Maybe this test also does the same as Labcorp's - quantifies over 43 IU/mL, but can detect down to 7 IU/mL??? Is so, it doesn't indicate that on their lab test summary.  Or maybe a Qualatative test was used instead of a Quantitative in your example?  

My comments were specific to Quest's HCV RNA Quant RT-PCR.

Method:  HCV RNA Quant RT-PCR  
Real-time polymerase chain reaction (PCR)
Linear range: 43 to 69,000,000 IU/mL
Alias: HCV viral load, HCV quantitation  
Reference Range: HCV RNA <43 IU/mL

Interpretive Information:
In patients with reactive EIA results, a negative HCV RNA result typically indicates resolved infection but does not rule out carrier status; negative results may also indicate a false-positive EIA result, false-negative HCV RNA result, or intermittent viremia for a carrier.
Results ≥43 IU/mL suggest active HCV infection.

Comment
Cancel
1669790 tn?1333666195
Comment
Comment
Submit Comment
190885 tn?1333029491
so what i'm getting is it could be a false positive??? so when i was 43 at end of week 4 maybe i didn't have any vl? that must be why they didn't seem like it was such a big deal at that point....billy
Comment
Cancel
190885 tn?1333029491
Comment
Comment
Submit Comment
1669790 tn?1333666195
Billy,
I don't believe that false-positive and false-negatives are frequent since they've refined their techniques in these tests, but I think this is more of a CYA.  I don't know the %, but false results are possible.  Maybe someone has more information on the amount of false reporting on the most recent tests??

I was posting this more to show the reference range and that results ≥43 IU/mL suggest active HCV infection.

Comment
Cancel
1669790 tn?1333666195
Comment
Comment
Submit Comment
Avatar universal
My labs machine does two things .. i can give you quantitive >15  
AND it can give "HCV Not Detected IU/mL"

Which is just gave me today when I received my 9 week vl test.

AST 16     ALT 11  

I am in shock.

3 weeks to go.

dm
Comment
Cancel
Avatar universal
Comment
Comment
Submit Comment
Your Answer
1669790 tn?1333666195
Answer
Know how to answer? Tap here to leave your answer...
Answer
Submit Answer
A
A
Recent Activity
3060903 tn?1398568723
Blank
Nighthawk61 I DO NOT KNOW THE WORD FEAR... Comment
7 hrs ago
408795 tn?1324939275
Blank
fretboard uploaded new photos
May 04
463897 tn?1448485050
Blank
MH Community Mgr commented on Bubulous's status
May 03
Blank
Weight Tracker
Track your weight over time
Start Tracking Now
Top Hepatitis Answerers
683231 tn?1438659664
Blank
flyinlynn
Auburn, WA
163305 tn?1333672171
Blank
orphanedhawk
Rural Mural, CA
446474 tn?1446351282
Blank
HectorSF
San Francisco, CA
1815939 tn?1377995399
Blank
pooh55811
Avatar m tn
Blank
can-do-man
IN
317787 tn?1460223707
Blank
Dee1956
DC
Hepatitis C Community Resources
RSS Expert Activity
233488 tn?1310696703
Blank
Marathon Running Done Over Many Yea...
May 21 by John C Hagan III, MD, FACS, FAAOBlank
233488 tn?1310696703
Blank
New Article on Multifocal IOL vs &q...
May 21 by John C Hagan III, MD, FACS, FAAOBlank
748543 tn?1443740527
Blank
TMJ/TMJ The Connection Between Teet...
01/15 by Hamidreza Nassery , DMD, FICOI, FAGD, FICCMOBlank
Top Hepatitis Answerers
683231 tn?1438659664
Blank
flyinlynn
Auburn, WA
163305 tn?1333672171
Blank
orphanedhawk
Rural Mural, CA
446474 tn?1446351282
Blank
HectorSF
San Francisco, CA
1815939 tn?1377995399
Blank
pooh55811
Avatar m tn
Blank
can-do-man
IN
317787 tn?1460223707
Blank
Dee1956
DC