Quantitative VS Qualitative

[iwillbeatthis]

I'm a little confused regarding the difference between the quantitative and qualitative tests.
Is the quant the regular PCR <43?

And I am not sure how a TMA differs from a PCR. "The Heptimax is a 2 part TMA not a PCR. I am looking for a PCR that only measures actual RNA without including dead virus particles".

Can someone clarify this for me?
Thanks,
Bree

[tayyabahmad]

What is difference between quant and qual pcr? My quant pcr is negative .can my qual pcr also negative?

[Jakied]

  the qualitative Pcr is more sensitive than the quantitative.  Quali checks for the virus

   Quanti checks for AMOUNT of the virus.

[iwillbeatthis]

thank you everybody.
Bree

[Cory255]

Qualitative viral load tests — These tests determine the presence of HCV RNA in the blood. This type of test is usually used to confirm chronic infection with HCV. If viral RNA is detected, a positive result is reported; if viral RNA is not detected, the test result is negative.

Quantitative viral load tests — These tests measure the amount of virus in one milliliter of blood. They are often used to assess whether or not treatment with interferon or interferon plus ribavirin is likely to be successful and, later, if treatment is working.

[eureka254]

There are a variety of different tests available besides Heptimax -- you can find a good description of each of them here:

http://www.pdfdownload.org/pdf2html/pdf2html.php?url=http%3A%2F%2Fwww.questdiagnostics.com%2Fhcp%2Ftopics%2Fheptimax%2Ffiles%2Fhep_c.pdf&images=yes

In regards to TMA vs PCR, you might find the below article of interest:

Hepatology. 2000 Oct;32(4 Pt 1):818-23.
"Detection of residual hepatitis C virus RNA by transcription-mediated amplification in patients with complete virologic response according to polymerase chain reaction-based assays."  Sarrazin C, Teuber G, Kokka R, Rabenau H, Zeuzem S.
Medizinische Klinik II, J.W. Goethe-University, Frankfurt am Main, Germany.
Abstract

"A considerable proportion of patients with chronic hepatitis C who achieve a virologic end-of-treatment response relapse after discontinuation of therapy. It is conceivable that polymerase chain reaction (PCR)-based assays with a lower detection limit of 100 to 1, 000 hepatitic C virus (HCV) RNA copies/mL are still too insensitive to detect residual viremia. End-of-treatment serum samples of 47 patients with a virologic relapse according to results of qualitative PCR assays (Amplicor HCV; Roche Molecular Systems, Mannheim, Germany) were tested by transcription-mediated amplification (TMA), an isothermal, autocatalytic target amplification method that has the potential to detect less than 50 HCV RNA copies/mL. Virologic sustained responders (n = 59) and nonresponders (n = 49) served as controls. In end-of-treatment serum samples of virologic sustained responders and nonresponders an almost complete concordance between PCR and TMA results was observed (98%). However, HCV RNA was detectable by TMA in end-of-treatment serum samples from 16 of 25 relapse patients (64%) who were HCV-RNA-negative according to Amplicor HCV version 1.0 (lower detection limit 1,000 copies/mL) and in 8 of 22 patients (36%) who were HCV-RNA-negative according to Amplicor HCV version 2.0 (lower detection limit 100 copies/mL). End-of-treatment alanine transaminase (ALT) levels of sustained virologic responders and TMA-negative relapsers were similar, whereas a trend toward higher ALT values was observed in TMA-positive relapsers compared with sustained virologic responders (P = 0.09). In conclusion, HCV RNA can be detected at the end of treatment by TMA in a considerable proportion of patients who were classified as virologic end-of-treatment responders with a subsequent virologic relapse according to PCR-based methods."

http://www.ncbi.nlm.nih.gov/pubmed/11003628?dopt=Abstract

[Trinity4]

I don't see the concern with dead particles.  Quantatative measures the amount of any HCV RNA virus in serum to the upper limit or sensitivity of the test.  Qualitatative determines only the presence of HCV RNA in serum to the upper limit of the test.  Absence of detectable HCV RNA in serum including dead particles is still UND.  With your RVR I would not be overly concerned other than to confirm you are UND.  If it were me, I would be comfortable with the Labcorp <43 but it's your EOT PCR so you should do whatever you're comfortable with.  

Trinity

[Bill1954]

Bree, a qualitative test provides a pos/neg result, quantitative testing issues an actual viral load; i.e. 2,200,000 IU/mL.

PCR and TMA testing are both nucleic acid tests, but use different methodology.

Heptimax uses both PCR and TMA methodology; PCR test sensitivity to 43 IU/mL, then TMA assay if <43 IU/mL.

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

“Real-time polymerase chain reaction (PCR), followed by quantitative transcription-mediated amplification (TMA) for samples with <43 IU/mL HCV RNA.

Linear range: 5 to 69,000,000 IU/mL
    
Alias: HCV viral load, HCV quantitation

CPT code*: 87522

Reference Range: HCV RNA <5 IU/mL”

--Bill

[iwillbeatthis]

thanks, but I'm still confused. what is the difference between quan and qual tests?
mine have always said RNA Quant RT PCR.
and why did someone say "The Heptimax is a 2 part TMA not a PCR. I am looking for a PCR that only measures actual RNA without including dead virus particles".

Is a Heptimax and the Quanta Sure the same as the <43 VL test, just more sensitive?

[Trinity4]

Quest's "HCV RNA QUALITATATIVE TMA" written on the report form as " HCV RNA QUAL TMA". As it's name suggests it's a qualitative and goes down to 5 IU/ml, the same sensitivity as Heptimax. At this point, you don't need numbers, just need to know whether you're UND.  Regardless of where the blood is drawn, the test is only run at the Nichol's Institute at Cupertino, CA, which supposedly has the highest standards.

Trinity