Rapid Oral HIV Test Has Disadvantages... TO TEST ΣΑΛΙΟΥ ΓΙΑ ΤΟΝ HIV KAI TA MEIONEKTHMATA TOY....

διαβάζουμε τη δημοσίευση στο Lancet Infect Dis. Published online January 24, 2012

Oι συγγραφείς τονίζουν την πιθανότητα λάθους, του test παρά τη μεγάλη του ειδικότητα, σε περίπτωση που το τεστ χρησιμοποιείται ευρέως σε περιοχές με χαμηλή επίπτωση του νοσήματος.

Οι ίδιοι δεν ευνοούν την ευρεία χρήση του σ’ αυτή την περίπτωση, ενώ επισημαίνουν την ανάγκη επιβεβαίωσης της διάγνωσης με τις παραδοσιακές αιματολογικές μεθόδους.

Προς γνώση και συμμόρφωση λοιπόν..

Στην Ελλάδα έχουμε δώσει παραπάνω σημασία σε αυτό που προβάλλουν οι Φαρμακευτικές από αυτό που ισχύει τελικά...


Όλη αυτή η εμπορία του πόνου καταλήγει σε τραγικά λάθη.

ακολουθεί το κείμενο των επιστημόνων..
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Lara C. Pullen, PhD
January 25, 2012 —

The oral HIV test has a 2% lower sensitivity but similar specificity compared with blood-based tests, according to pooled data from a new review and meta-analysis performed by 
Nitika Pant Pai, MD,
from the Department of Medicine, McGill University, and
the Division of Clinical Epidemiology and Infectious Diseases, McGill University Health Center, Montreal, Canada, and colleagues,
published online January 24 in Lancet Infectious Diseases.

Similarly, the oral test (OraQuick, OraSure) has a high positive predictive value (PPV) in high-prevalence settings (98.65%; 95% credible interval, 85.71% - 99.94%) that is comparable with the PPV of blood tests in the same setting (98.50%; 95% credible interval, 93.10 - 99.79).

However, the PPV in low-prevalence settings was lower for oral (88.55%; 95% credible interval, 77.31% - 95.87%) compared with blood (97.65%; 95% credible interval, 95.48% - 99.09%) specimens.

The differences found in these head-to-head comparisons should be considered when planning worldwide use of the popular oral test.

The authors of the study note that although the specificity estimates were similar to the manufacturer's claims, the sensitivity estimates of the oral test fell short.

In an accompanying comment, Chi Chiu Leung, MD, and Shui Shan Lee, MD, from the Chinese University of Hong Kong describe the clinical application of the study:

"Oral fluid-based Oraquick offers the attraction of being more convenient and non-invasive. 

However, although its better acceptability might promote access to HIV screening, this seems to be at the cost of a substantial false-positive rate, even though the estimated specificity of 99.74% might have dwarfed that of most other diagnostic tests in use.
 
This factor must be considered for test interpretation, especially when the availability of such a rapid test allows penetration of screening programme into lower-risk groups."


The editorialists explain that the lower PPV for oral specimens was more noteworthy in low-prevalence settings (HIV < 1%).

They also emphasize the PPV values in their commentary because they feel that it may be most relevant to clinicians.

The PPV provides the actual probability that the patient being tested is HIV-positive.

Thus, although the oral test is highly specific, the subtle difference between the false-positive rates in that test vs those in the blood-based tests becomes substantial when the HIV prevalence is less than 1%.

Although Dr. Leung and Dr. Lee appear to discourage rapid adoption of the oral HIV test because of its lower PPV, they do note that confirmatory testing (both positive and negative) is generally considered important for such a major disease as HIV.

Repeat testing would decrease the concern about the lower PPV of the oral test.
Jacqueline A. Hart, MD contributed to this article.

The study was supported by the Canadian Institutes for Health Research.
The study authors, as well as the editorialists, Dr. Leung, and Dr. Lee, have disclosed no relevant financial relationships.

Lancet Infect Dis. Published online January 24, 2012