5 replies to this topic

[MichelleH]

Hi everyone,

I am trying to locate something I read a week ago regarding BCR-ABL testing units being used for research tools and not Diagnostics.  Is that the case for all testing?

The lab that my son's bloods get sent to have changed recently to  "As of 6/5/13 BCR-ABL testing in the Molecular Haematology laboratory is performed using a Qiagen assay."  Both old and new reports claim to be on IS method.  Are there Assay's that are more accurate than others?

[Trey]

Michelle,

You have seen one of my several references to CML PCR testing where I have explained that the PCR manufacturers say the equipment and reagents are:

"For Research Use Only. Not for use in diagnostic procedure".    They should follow this with "wink, wink, nod, smile".

Here are some examples:

http://www.qiagen.co...cr-Controls-Kit

"For Research Use Only. Not for use in diagnostics procedures. No claim or representation is intended to provide information for the diagnosis, prevention, or treatment of a disease."

http://www.cepheid.c...t-catalog/<br/>

(see asterisk at bottom of page) "For Research Use Only. Not for use in diagnostic procedure"

http://www.roche-as....abl_V090310.pdf

(Top of first page) "For life science research use only. Not for use in diagnostic procedures. For in vitro use only"

And so on......these were just the first three I picked at random.  I am not aware of any exceptions, but there may be.  But that would not change the principle here.

Of course everyone ignores this and proceeds to use PCR testing for diagnostic purposes, and it is helpful to those of us with CML, especially those with low level minimal residual disease (MRD).  Hence the winking et al.

But there is a good reason why the manufacturers equivocate about their equipment.  They are not reliable enough for medical diagnostics, so major decisions should not be based on what one PCR says.  [NOTE: typo fixed per Phil's input below -- thanks]

All of the modern PCR testing equipment (about 5 years old or less) is relatively about the same accuracy, assuming controlled testing conditions (big assumption).  But they all report results differently.  One lab's .3% could be another lab's 10.0% so they are not comparable.  Any changes in lab used or equipment or processes or calculations requires a reset in the individual patient's trend line.  A trend is best defined as three in a row, but at least two.

I am not anti-PCR testing; I have probably had a couple dozen done on me.  I get one every 6 months and I believe I am better off for having the information they provide.  But there are many variables, and the PCRs are all different, and no two labs or equipment are directly comparable even if International Scale is applied. 

So we should all take the warnings to heart and use PCRs as they should be used:  Use trends only, from the same lab, with the same equipment, using the same calculations/scale, assuring "speedy" delivery from your vein to the PCR.

[PhilB]

Small typo there Trey - I think you meant to include a 'no' in 'so major decisions should be based solely on what one PCR says.'

[Trey]

Thanks.  Fixed it above.

[CallMeLucky]

Trey, wondering if your detective skills might be better than mine.  I'm now having PCR run through Genoptix, which is owned by Novartis.  I checked their site and found some interesting statements.

Wondering if you could find anything more along the lines of what you have above for this particular lab since I was unable.

http://www.genoptix....2-dos-final.pdf

"Test Performance Characteristics

Unless otherwise noted, all tests were developed by, and their performance characteristics

determined by, Genoptix, Inc. They have not been cleared or approved by the U.S. Food and

Drug Administration. Current FDA guidelines indicate such clearance is not necessary. These

tests are used for clinical purposes. They should not be regarded as investigational or for

research. This laboratory is certified under the Clinical Laboratory Improvement Amendments

of 1988 (CLIA-88) as qualified to perform high-complexity laboratory testing.

If Genoptix changes its analytic methodology such that test results or their interpretation

may be significantly different, these changes will be communicated to clients."

The key statement above is "unless otherwise noted"  below is the full description of the BCR-ABL PCR test they offer and no where does it state it should not be used for diagnostic purposes.  I'm wondering if Novartis is willing to stand behind this test more than some other labs.

Regardless though I still agree with everything you wrote about the PCR itself, it does seem like there is some variability.  But I am wondering if not all labs are equal.

Genotrace® Assay for

Chronic Myelogenous Leukemia

(CML)

This quantitative real-time RT-PCR assay detects fusion transcripts resulting from

breakpoints in various clustered regions of the BCR gene fused to the ABL gene: e13a2,

e14a2, the major breakpoint region; e1a2, the minor breakpoint region; and e19a2,

the micro breakpoint region. The presence of these breakpoints is characteristic of the

reciprocal translocation between the long arms of chromosome 9 and chromosome 22

[t(9;22)] (Philadelphia chromosome). BCR-ABL is required for the diagnosis of Chronic

Myelogenous Leukemia (CML) and is present in a subset of acute leukemia (~20% of

Acute Lymphoblastic Leukemia [ALL]) cases. Minor and micro BCR-ABL breakpoints have

been associated with certain phenotypic features of CML and may also confer different

prognostic significance. CML patients in chronic phase and carrying predominantly minor

BCR-ABL transcript tend to have a more "monocytic" CML. CML patients carrying a micro

breakpoint BCR-ABL transcript tend to have a more "neutrophilic" CML. Reporting will be

on the International Scale (IS) when the BCR-ABL1 fusion transcripts result from a major

breakpoint (b2a2 and b3a2). The IS is anchored to the baseline BCR-ABL1 expression

level from the International IRIS trial (100% IS) with a major molecular response (MMR)

corresponding to 0.1% IS.

Reverse-Transcriptase Polymerase Chain Reaction (RT-PCR). Serial Reporting will be

provided when repeat samples are submitted. Results are reported on a scale of

0.001% - 100%.

• Clotted, hemolyzed or frozen samples ARE NOT acceptable.

• Samples should be shipped as soon as possible, but at least within 48 hours post

collection.

• Store at room temperature until transport.

• Ship at room temperature.

• In excessive heat, ship with cold pack. DO NOT freeze cold pack. Refrigerate only.

Peripheral Blood:

• 4-5 mL in purple-top (EDTA) tube.

• Gently invert tube 8 times after draw.

• If the WBC is < 5,000: 2-3ml in two (2) purple-top (EDTA) tubes.

Bone Marrow Aspirate:

• 2-3 mL in purple-top (EDTA) tube.

• Gently invert tube 8 times after draw.

Monday through Saturday/4-8 days

Incomplete information on a test requisition may cause a delay in reporting.

Also noted that it appears Quest does not have a disclaimer.  http://www.questdiag...c=TH_bcrablQuan

[Trey]

Genoptix and Quest are labs, not PCR equipment or reagent manufacturers.  It is the manufacturers which try to cover themselves with the " research only" disclaimer, not the labs you discussed.  So your real question might be which PCR machine and reagents Genoptix and Quest use for BCR-ABL, then look at the manufacturer website for the disclaimers. 

This article discusses in a not-easy-to-read manner the variability of PCRs, and how future standardization of PCR reagents could potentially improve reliability. 

http://bloodjournal....2/e111.full.pdf