QFT News - Progression.

As Rog has reported, Cellestis have released their latest QFT News which is primarily all about the superiority of QFT in identifying those with latent TB that will progress to active TB as demonstrated by the large scale, longitudinal study by Diel et al.


It's a very worthwhile read.


At the same time, the Company have released a web resource dedicated to the issue of TB Progression. 


Here is a diagram taken from the Cellestis documentation that summarizes the comparison between QFT and TST very neatly.

A Big Diel.

As Rog has already reported, the results of the long awaited longitudinal study by Diel has finally been formally published. Whilst I have discussed the findings from this study previously here and here its importance is such that it is well worth discussing again.

Firstly (and we will see this in the following), this study gives the Company some really solid, incontrovertible evidence of the efficacy of QuantiFERON TB that they will no doubt be able to use to complement their already extensive marketing. My understanding is that whilst the results of this study have been available for several months the Company is prevented from using them until it has been officially published in print in a peer reviewed journal. That now appears to have been done by the American Journal of Respiratory and Critical Care Medicine, here.

This report is actually an update of Diel's longitudinal study that was published back in 2008. It was that study that enabled me to understand that "It's all about Progression". If you are suitably enthused you might want to click on that link.

Longitudinal studies (the longer the better) are very important in convincing the medical community of the true effectiveness in the real world of treatments, interventions, diagnostics etc. It takes no mental giant to work out why that is. Furthermore longitudinal studies are expensive both in time and resources. They are therefore "worth their weight in gold" (as long as they support the original contention, of course). The other attribute of a study that adds weight to it's value is the size of patient group.

This study has followed 954 close contacts of active Tb patients over a mean period of 3.5 years.

I believe that the results from such a study would be hard to deny.

You can read the results for yourself but in summary the results are:

QFT did not miss a single contact that subsequently progressed to active TB. Let me say that another way - of the 756 patients that QFT identified as not having latent TB, not a single one went on to develop active TB.

In comparison, the TST skin test, even at the very tight 5mm cutoff, missed 11% (2) of the contacts that subsequently went on to develop active TB. At the commonly used 10mm cutoff the TST missed a massive 47% (9) of the contacts that subsequently went on to progress to active TB.

Now, the scientists can apply all sorts of fancy statistics to that but to me it is summarised with the statement that using the TST would have resulted in either 2 or 9 people being turned out into the community to later develop active TB and potentially spread it to others. On the other hand, QFT allowed nobody that later progressed to active TB to be turned out to spread TB further.

As a side note, this statistic alone, destroys the value of the "use TST then retest the positives with QFT" proposal that has been suggested in some jurisdictions. Under such a program those 2 or 9 people would never have been tested with QFT.

But it gets better, a lot better.

On the other side of the coin the TST would have resulted in either 555 or 207 people (depending upon which cutoff was used) to be treated for latent TB. QFT on the other hand would have determined that only 147 needed to be treated.

Using the TST you actually end up with an unenviable choice. Use a 5mm cutoff, treat a massive 555 people for latent TB and still miss 2 people that later progress to active TB or; use a 10mm cutoff, reducing the number of people to treat to 207 but miss 9 people that later progress to active TB.

Surely it makes sense to use QFT, treat only 147 people and miss not a single progression.

So, a huge saving in costs, a huge reduction in people subjected to antibiotic treatment and not a single progression missed.

I believe it will be very hard for anybody, when faced with these results, to deny the superiority of QFT based TB Control program over a TST based system. I look forward to these results permeating throughout the TB Control Community. I would imagine that there are many TB Controllers who have been waiting for such ammunition.

Dear Anonymous.

G'day "Anonymous",

You have commented:

"More grandstanding from the master of sophistry masked in verbal diarrhea. If this is a thesis, your pretensions to academia fail, but keep up the ramp as your "investments" dwindle. If your ramp succeeds you may be able to sell to some more "suckers" north of 2.50 as would appear the motive behind this so-called thesis."

I always appreciate comments that dispute my thoughts that are presented with a modicum of reasoning and logic. After all, I am not the fount of all wisdom. The wisest thing that I do is to listen to others and learn.

Unfortunately, your comments don't seem to even make the vaguest attempt to reach for anything of value to anybody.

Generally, I no longer bother to reply to comments that consist purely of unsupported criticism. However, whilst your postings clearly fall into this category, I am making an exception. (It's my blog - I'll break my own rules if I wish)

I actually have no problem whatsoever in your considering my posts to be "verbal diarrhoea". Furthermore, it is within your rights to express that opinion - even though it adds nothing at all to the discussion or the community knowledge. Perhaps my ramblings add nothing either but at least they have an intention of doing so and I am willing to support them with a logical argument.

As to sophistry. Depending upon which definition you use, this could be considered a compliment or an insult. Whilst I would (of course) prefer the first, I suspect that your intent is the latter. The problem that you have with that accusation is that sophistry (used in the negative sense) implies the presentation of a logical argument with the intent of deceiving somebody.

As a starting point, you and other readers have my assurances that I have no intent or interest in deceiving anybody.

Perhaps a better assurance might be achieved by considering my more than ten years of public postings. I am simply not smart enough to maintain a deception for such a long period of time.

Ultimately, however, it is the content of my posts that, I believe, speak most strongly for my integrity. I have always provided in detail the reasoning behind my views. After all, I would achieve no personal satisfaction from simply spouting comments with no reasoning applied. It is my (sometimes failed) attempt to build my skills of expression and logic that drive me to make the effort to write my postings.

You make the strange accusation that I am a stock ramper. If I am then I am a very poor one. A successful share ramper should by now be sitting a massive pile of ill gotten gains. I assure you that I am not.

More specifically, you make the accusation that my post is a ramp for CST. I am wondering if you have actually read it carefully. If you do then you will see that firstly it does not suggest any action to anybody other than that they make decisions for which they are willing to account to themselves for. The result of such a suggestion (if I was bold enough to believe that my post may actually impact anybody's thinking) could just as equally be to sell CST shares as to hold or buy.

In the end, I am happy with who I am and am enjoying the never ending task of becoming more proficient at the things that I do. I am by no means under the misapprehension that my posts are revealing some hitherto unknown secrets - they are nothing more than a result of my own personal thoughts and my attempts to translate them into the written word. If the result of that is postings that you find objectionable then there is little that I can do about that, other than to suggest that you don't read them or, better still, address them with contrary, logically supported thoughts of your own. (I would respectfully request that if you would like to do that then you select a nickname for yourself - addressing posts from "Anonymous" is a little tiresome and results in unnecessary confusion)

Finally, (here's some irony) it strikes me that perhaps the reason behind your attack on me exemplifies exactly the point that I make in my post. I suspect (but admittedly have no evidence) that you have at some point made some investment decisions regarding CST that you now feel unhappy about. You now wish to blame somebody else (me, it seems) for the decisions that you have made. If that makes you feel somewhat better about yourself then I am more than willing to passively provide that need - as sad as it is.

Try to have a great 2011.

(With apologies to other readers. It is always my intent to provide posts of interest. In this case, please forgive my indulgent actions in defending myself).