Newsletter No. 2/2009

As usual this time of the year Düsseldorf will host the World Forum for Medicine - MEDICA 2009 (November 18-21, 2009), and everything will be well-prepared to enable the diagnostic community discuss and plan. We from DIARECT would like to invite you to meet with us and to talk about everything you need in antigens as well as immunoassay stabilization components and substrates. You will find us at the booth of our partner company, SurModics, Inc., in hall 03/C16-9. The DIARECT management will be attending Medica from Wednesday to Friday (November 18-20), and we are looking forward to seeing you there. To arrange an appointment, please give us a call or send an email or fax.

The question of what the true definition of ANA (antinuclear antibodies) should be causes quite a stir within the diagnostic community. However the answer seems to be quite clear: ANA as a diagnostic technique developed with the advent of the immunofluorescence assay (IFA) which at first used cryostat sections of rodent organs and subsequently, as a considerable improvement, the human epithelioma cell line, HEp-2.
In this respect ANA developed into an established and sensitive "incoming inspection" of sera from patients with reasonable clinical indications. And a positive ANA result was typically followed by more specific antibody testing based on distinct antigenic targets for a more precise diagnostic assessment.
So far so good!
However, more than ten years ago when more and more reliable and highly purified recombinant individual antigens became available, a number of diagnostic companies were striving towards an alternative design, namely the combination of wisely selected individual antigens in profile as well as screening assays - that time mostly as enzyme-linked immunoassays (ELISA). This point in time hallmarks the beginning of a still open and for a short time renewed and rather agitated debate on the most appropriate strategy to analyze problematic sera that arrive at a clinical lab with the question mark "ANA".
This debate on multiparametric vs. IFA testing reached a peak at last year's ACR meeting in San Francisco, continued at the AACC meeting in Chicago in July 2009 (c.f. William Check, September 2009, CAP TODAY: Making sense of the ANA hodgepodge) and again at the ACR meeting last month in Philadelphia. Even the 6th national meeting of "Deutsche Vereinte Gesellschaft für Klinische Chemie und Laboratoriumsmedizin" (German Society for Clinical Chemistry and Laboratory Medicine) in Leipzig last month (www.dgkl2009.de) focused on this question (Philipp von Landenberg, ANA - immunofluorescence or ELISA).
The up-to-date situation of this debate will be communicated by Dr. D. Roggenbuck's (Dahlewitz) ACR congress report summarizing the objectives of the meeting of the "IUIS/WHO/AF/CDC Committee for the Standardization of Autoantibodies in Rheumatic and Related Diseases".
Although the outcome of this ongoing controversy has still not been determined, and the mandatory 'accurate' answer in all likelihood will not even be found by the experts- so to speak "ex cathedra" -, one undisputable necessity will remain:

The requirement for an extensive panel of distinct and clinically approved specific human autoantigens for unequivocal serological diagnosis.

The IUIS/WHO/AF/CDC Committee for the Standardization of Autoantibodies in Rheumatic and Related Diseases convened at the annual congress of the American College of Rheumatology held in Philadelphia October 16th-21st, 2009. The session organized by the coordinators Angela Tincani and Edward K.L. Chan and moderated by Pier Luigi Meroni was entitled: Autoantibodies in Diagnosis and Follow-up of Rheumatic Diseases. Is There a Revolution in the Use and Interpretation of Diagnostic Tests for Rheumatic Diseases?
The coordinators defined the following objectives for the session:

• identify the common clinical problems associated with inaccurate ANA results


• describe the current technologies that clinical laboratories are using and how physicians should be engaged with the clinical laboratory


• outline the proper use and interpretation of autoantibody testing in a clinical rheumatology setting


• state the role and ethical obligations of the manufacturer, diagnostic laboratory and the clinician in the production, sale and use of autoantibody diagnostic kits

The moderator Pier Luigi Meroni, MD gave a short introduction regarding ANA detection and reminded the participants of the discussion at the 2008 ACR meeting last year. False reports of ANA by major laboratories in the US employing non-immunofluorescence techniques were criticized. This was the committee's reason to deal with this issue und organize the current session.
The first speaker, Merlin R. Wilson of New Orleans, LA, presented cases of several inaccurate ANA reports he came across while running a specialized referral laboratory. He received sera from patients with suspected rheumatic disease which had been referred to other private laboratories earlier. Reports given by these laboratories did not match the clinical picture of patients and were sent by doctors to his laboratory running immunofluorescence tests for retesting. He presented two extreme examples showing discrepant data where the immunofluorescence data did support the clinical suspected diagnosis.
Eng M. Tan, of La Jolla, CA, one of the fathers of autoimmune diagnostics and the discoverer of the Sm autoantibody in patients with Sjögren's syndrome gave an overview of tests available for rheumatic diagnostics. He discussed screening ANA assays and compared immunofluorescence on HEp-2 cells with enzyme immunoassays and multiplex bead assays. He reminded of the meaning of specificity and sensitivity in terms of ANA detection. He stressed the fact that doctors are used to understanding ANA assessment as a sensitive test for screening.
Luis Eduardo C. Andrade of Sao Paulo, Brazil, presented algorithms for ANA testing and interpretation. He talked about his experience in Brazil regarding the use of ANA and presented the Brazilian approach to deal with the rising demand in ANA detections.
Marilyn Lightfoote of Rockville spoke as representative of the Food and Drug Administration (FDA) about the role of her organisation in ANA testing. She explained the work of the FDA in terms of product registration and clearly pointed out limitations regarding post-market surveillance of diagnostic products.
During the subsequent discussion several rheumatologists expressed their uneasiness and anger with the current state of ANA testing in the USA. Laboratories seem to report wrong results and fail proficiency tests of external quality control examinations. There is a clear demand to require that laboratories state the method used for ANA detection. Laboratories should critically check the technique employed and consider immunofluorescence testing as gold standard. The FDA was asked to have a look into the matter and use their authority to improve the situation.

SurModics, a leading producer of protein stabilizers, synthetic blockers and other IVD reagents, has expanded their partnership with DIARECT to conveniently offer their advanced line of BioFX TMB substrates to diagnostic customers in Europe. These substrates are specially formulated to assist in the rapid detection of bioanalytes used in quantitative and qualitative ELISAs and other immunoassays, and were among the first to be developed using stable, one-component, aqueous buffer compositions that do not contain aprotic solvents, such as DMSO, to allow for easier handling and waste disposal.

In a comparison study among leading TMB manufacturers (Figure 1), the BioFX Super Sensitive TMB demonstrated the fastest enzyme kinetics among leading competitors allowing for the development of quick and sensitive tests. The BioFX TMB substrates are currently available in multiple kinetic formulations, including the BioFX TMBC, TMBW, TMSK, and TTMB which are specifically formulated in order easily customize the dynamic range in any test without dilutions and without compromising assay sensitivity.