An interview with Robert Notenboom, PhD, Consultant for Phoenix

Q: Does Phoenix have a theme for AACC 2009?

Notenboom: Our theme is educating the health care worker on the problems with the current Syphilis algorithm: “Flipping the Treponemal Paradigm.” The fortuitous discovery by Wassermann in 1906 that cardiolipin could be used for the sero-diagnosis of Syphilis led to great optimism and universal acceptance of a paradigm that is still reflected in the testing algorithms in many jurisdictions. While eventually more specific treponemal antibody tests became available, in most instances the testing process still starts with applying a nonspecific (cardiolipin-based) manual test. Once a negative result is obtained, no further testing is routinely carried out and a treponemal infection is ruled out. This practice could lead to the erroneous conclusion that sensitivity of nonspecific tests is “adequate.” However, data published by the CDC shows the serious limitations of these tests in terms of specificity and sensitivity.

We suggest that the following algorithm based on TREP-SURE™ is more reliable and cost effective than the current/established one. (Flipping the Treponemal Paradigm … New Approach)

Further simplification of this algorithm is likely to happen once the benefits of Trep-ID™ are firmly established.

Q: Which products are you featuring, and why?

Notenboom: We are featuring our new product: TREP-SURE third-generation EIA, which is FDA cleared. This product has a reduction in both false-negative and false-positive results.

We are also featuring a new product, Trep-ID, currently in clinical trials. The use of the new Trep-ID is likely to provide a “fingerprint” of the patient’s treponemal antibody status and shows promise as an indicator of treatment failure or reinfection. The benefits of Trep-ID are considerable as many patients following “adequate treatment” will not sero-convert to negative or remain “serofast.” In such patients Trep ID can establish a new baseline.

Q: Tell us about these products you’re featuring. What are the competitive advantages, and/or how do they represent advances over previous versions?

Notenboom: TREP-SURE represents a new approach to Syphylis testing. It offers better sensitivity and increased specificity. The rapid plasma reagin (RPR) blood test for Syphylis is a difficult test to interpret when low levels of nontreponemal antibody are present. The test may be negative during early or late infection. Using immuno-blots or western blots as new confirmatory tests to resolve discrepant test results and based on about 3 million results, the characteristics of TREP-SURE are 99.9% sensitivity and 99.9% specificity. It should be noted that no serum dilution is required.

A lot of positive RPR results are false-positives, especially when screening low-risk populations.

In addition, this new approach is more efficient, and results can be reported on the same day. EIA is completely automated, whereas RPR is a manual, labor-intensive test.

The overall cost of the two approaches is comparable, depending on the test volume.

To sum up, advantages of the TREP-SURE Screen ELISA include:

  • Samples (serum or plasma) do not require predilution: 100 µL of sample can be added directly to the well.
  • The assay detects all isotypes, which is essential in order to identify all patients with early disease.
  • There is a very low number of “equivocals,” negative results in low O.D. Values, while most positives generate results greater than 2.5 O.D. Values.
  • There is a high sensitivity for all stages of Syphylis disease (greater than 99.9% in active Syphylis, and greater than 90% in dark field positive patients).
  • Specificity is greater than 99.9%, with no cross reactions due to various other conditions, such as Lyme Borreliosis or pregnancy.
  • There is a high tolerance for potentially interfering substances, such as lipids and hemoglobin, and samples can be taken directly from the centrifuged blood clots.
  • Incubations are carried out at 37°C, reducing variation due to changes in temperature.
  • TREP-SURE is well-suited for automation, with results that can be integrated in a laboratory information system through bar coding.

Q: Will Phoenix be making presentations or demos in the booth during exhibit hours?

Notenboom: We will be featuring product displays and data discussion.

Q: Looking beyond AACC, what can laboratories expect to see from Phoenix in the future?

Notenboom: Release of its new Trep-ID ELISA, which will fingerprint antibodies the patient expresses to a T. pallidum infection and marketing of the TREP-SURE for blood donor screening.