PATENTED* DUAL PATH PLATFORM
(DPP®) TECHNOLOGY
DPP Information
*United States Patent #7,189,522 issued March 2007.
Patent protection is also are pending  in several foreign jurisdictions worldwide

CHEMBIO has developed a new and innovative chromatographic immunoassay technology--Dual Path Platform (DPP®)--for rapid, point-of-care diagnostic testing of a wide variety of analytes.  This technology offers significant advantages over  Lateral Flow (LF) technology.

DPP® Video Files
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CORPORATE COMMENTS:
Javan Esfandiari, Senior Vice President of R&D jesfandiari@chembio.com commented that “The independent flow paths of DPP®  sample and conjugate assays increase the efficiency of antibody binding to the immobilized antigen. This has resulted in improved sensitivity in several different assays Chembio’s R&D team is currently developing. The sample delivery efficiency for all samples has been substantially improved via DPP®. This will facilitate the development of new rapid tests using oral fluid, for example.”

DPP® TECHNOLOGICAL ADVANTAGES :

• Significantly increased analytical and clinical sensitivity.
  • DPP® HIV rapid tests results show substantially improved sensitivity, from 10-50X more sensitive than LF!
  • Independent migration paths for the sample and conjugate account for this increased sensitivity coupled with a more effective binding of the analyte to the binding site in the test zone prior to the reaction of the conjugated marker with the test zone complex.
• Decreased overall assay interaction time – It’s Faster!
  • DPP® can use either dry or liquid conjugate systems.
  • Samples such as blood, feces, and saliva are known to migrate very slowly in conventional LF assays but with separate and independent migration paths sorbent material may be utilized to permit faster migration without the concern for the conjugate migration requirements.
  • Speed of DPP® assays are enhanced, as well as sensitivity, due improved background clearance from better uniformity and consistency of migrating conjugate particles in the absence of the sample particles.
• DPP® is able to effectively resolve normal aggregation/agglutination migratory issues, a common concern  in LF assays with large particle analytes (e.g., bacteria):
  • In DPP®, the bacterial samples (after filtering) are applied directly to the test site and immobilized while the marker conjugate is free to migrate without the sample to the test zone.
  • This approach allows DPP assays to be extremely sensitive and specific.
• Enhanced multiplex capability with independent and simultaneous delivery of samples!
  • DPP® provides multiple analyte results with a high degree of sensitivity without compromising specificity due to cross-reactivity as is common in other LF methods.
  • Analytes able to migrate independently without the conjugate and reach the test zone independently and are thus able to bind equally so that the same level of sensitivity is maintained across all different analytes (e.g., HIV&TB, or HIV 1/2, etc.).
  • Easier to read results due to the fact that  different colored latex particles can be used to conjugate different antigens or antibodies provided in the conjugated pad or in the buffer solution.
  • Up to 5 test lines per cassette.
• Easier and more user friendly test procedure:
  • DPP reduces the time to results when compared to conventional LF by providing a visual color at the test site for the user to note when it disappears that then it is time to add the buffer at the test site rather than wait for a predetermined amount of time after adding the sample to add the buffer solution to the assay.
• Adaptable to multiple sample types:
  • Able to run different types of body fluids including: blood, serum, oral fluids, sputum, urine, feces, etc. and  still maintain a high level of sensitivity.
  • Able to provide highly sensitive and specific results while using minimal sample volumes.
  • Able to test for the presence of any ligand.
• Diverse potential applications for DPP®!
  • DPP® has potential applicability in a multitude of diverse applications where LF intellectual property restrictions combine with the need to provide faster and more accurate results coupled with the feasibility of expanding a multiplexed test parameter, such as:
    • Medical Diagnostics
    • Consumer OTC Diagnostics
    • Animal Health & Veterinary Diagnostics
    • Food Safety & Pathogen Screening
    • Environmental Sample Screening
    • Bioterrorism
    • Forensic Detection
    • Other Unique Agricultural & Industrial Uses

 DPP® CORPORATE BUSINESS STRATEGY:

Chembio has completed several new products and others in development utilizing its new DPP® technology.  These products include single analyte, multiplex and confirmatory assays for a number of infectious diseases includ.  TB, and other infectious diseases. These studies confirm the advantages of DPP® technology over single-path LF designs commonly employed in today’s rapid diagnostic assays. In March 2005, Chembio announced that it had filed a series of patent applications with the United States Patent and Trademark Office (USPTO) regarding the DPP® technology, and since then, has filed in several other foreign jurisdictions worldwide. In March 2007, Chembio was issued United States Patent Number 7,189,522 for its Dual Path Immunoassay device. Additional patent protection is pending in the US and worldwide. Chembio plans to develop new assays using DPP and is actively pursuing licensing agreements with several interested companies. Lawrence Siebert, President & CEO of Chembio, commented, “We believe that our Dual Path Platform is an extremely valuable technology and that we will be able to both develop new tests using the technology as well as license the technology to other companies interested in using this innovation in their test applications.”

For more information regarding this technology contact the following CHEMBIO DPP® representatives:

Research & Development:

Javan Esfandiari,
Senior VP, Research & Development
jesfandiari@chembio.com

Tel. No. (631)-924-1135 Ext. 112
Fax No. (631)-924-6033

HIV 1 /2 STAT-PAK® Assay
HIV 1 /2 STAT-PAK® Dipstick Assay
SURE CHECK® HIV 1/ 2 Assay
Product Information

By the end of 2007 there were approximately 33 million people living with HIV/AIDS including 15.5 million women and 2 million children under the age of 15. Nearly 3 million people were newly infected with HIV/AIDS. In the same year, 2 million people died of HIV/AIDS-related causes.
HIV/AIDS is caused by infection with Human Immunodeficiency Virus, HIV 1 or HIV 2. HIV 1 is the most frequently found strain worldwide. Infection with HIV 2 is found primarily in West Africa, although infections have been identified in other areas of the world.

HIV is spread by sexual contact with an infected person, by sharing needles and/or syringes (primarily for drug injection) with someone who is infected, or, less commonly (and now very rarely in countries where blood is screened for HIV antibodies), through transfusions of infected blood or blood clotting factors. Babies born to HIV infected women may become infected before or during birth or through breast-feeding after birth. Patients with HIV/AIDS and HIV/AIDS related diseases usually have a high level of the antibody to the viruses.

The standard screening test for antibodies to HIV is the enzyme immunoassay (EIA) or ELISA which is widely used in the United States and around the world. This test requires two visits to a clinic or medical facility; one to receive pretest counseling and to have blood drawn for HIV testing, and the second to receive test results and additional counseling and if needed referrals. Rapid, point-of-care (POC) tests have been developed which produce results within 20 minutes or less and allows testing, counseling and referrals to be accomplished in one visit. Rapid tests are less costly for testing agencies to perform due to the fewer outreach visits required to deliver results. Patients receive counseling, test results and referrals (if warranted) in one visit. Also, studies have shown that rapid tests are as sensitive and specific as conventional immunoassays.

Chembio Diagnostic Systems, Inc.’s SURE CHECK® HIV 1 / 2, HIV 1/ 2 STAT-PAK® and HIV 1/ 2 STAT-PAK® Dipstick tests are easy-to-perform, single-use diagnostic tests for the rapid, visual detection of antibodies to HIV 1 and HIV 2.

Assay Features

Convenient & Cost Effective

• Ideally suited for field and point-of-care testing
• Minimal sample size required—5 µl (assay dependent) fingerstick orvenous whole blood, serum or plasma
• Room temperature storage
• Long shelf life
• No special laboratory equipment required

Time & Labor Saving

• Ready-to-Use Reagents
• Simple procedure
• Total test time of 10 to 15 minutes (assay dependent)
• No special equipment required
• Results are easy to interpret

Reliable Results

• Built-in IgG procedural control
• Highly sensitive and specific

New! DPP® HIV 1/2 Screen
for Use with Oral Fluid or Blood Samples
Product Information

By the end of 2007 there were approximately 33 million people living with HIV/AIDS including 15.5 million women and 2 million children under the age of 15. Nearly 3 million people were newly infected with HIV/AIDS. In the same year, 2 million people died of HIV/AIDS-related causes.
HIV/AIDS is caused by infection with Human Immunodeficiency Virus, HIV 1 or HIV 2. HIV 1 is the most frequently found strain worldwide. Infection with HIV 2 is found primarily in West Africa, although infections have been identified in other areas of the world.

HIV is spread by sexual contact with an infected person, by sharing needles and/or syringes (primarily for drug injection) with someone who is infected, or, less commonly (and now very rarely in countries where blood is screened for HIV antibodies), through transfusions of infected blood or blood clotting factors. Babies born to HIV infected women may become infected before or during birth or through breast-feeding after birth. Patients with HIV/AIDS and HIV/AIDS related diseases usually have a high level of the antibody to the viruses.

The standard screening test for antibodies to HIV is the enzyme immunoassay (EIA) or ELISA which is widely used in the United States and around the world. This test requires two visits to a clinic or medical facility; one to receive pretest counseling and to have blood drawn for HIV testing, and the second to receive test results and additional counseling and if needed referrals. Rapid, point-of-care (POC) tests have been developed which produce results within 20 minutes or less and allows testing, counseling and referrals to be accomplished in one visit. Rapid tests are less costly for testing agencies to perform due to the fewer outreach visits required to deliver results. Patients receive counseling, test results and referrals (if warranted) in one visit. Also, studies have shown that rapid tests are as sensitive and specific as conventional immunoassays.

Chembio Diagnostic Systems, Inc.’s DPP® HIV 1/2 Screen, SURE CHECK® HIV 1 / 2, HIV 1/ 2 STAT-PAK® and HIV 1/ 2 STAT-PAK® Dipstick tests are easy-to-perform, single-use diagnostic tests for the rapid, visual detection of antibodies to HIV 1 and HIV 2.

New DPP® HIV 1/2 Screen
for Use with Oral Fluid, Blood, Serum and Plasma Samples
Patented DPP® System

Assay Features:

• Enables direct binding of sample to antigen
• Sharp & Distinctive Visual Results
• Simple, Flexible & Safe
• Use with Non-Invasive Oral Fluid Sample and all Blood Matrices
• Diluted Sample is Contained in Closed Vial, Available for re-test
• All of Chembio’s HIV Tests Convenient & Cost Effective
• Ideally suited for field and point-of-care testing Minimal sample size required—5 µl (assay dependent) fingerstick orvenous whole blood, serum or plasma
• Room temperature storage Long shelf life
• No special laboratory equipment required Time & Labor Saving
• Ready-to-Use Reagents Simple procedure
• Total test time of 10 to 20 minutes (assay dependent) No special equipment required
• Results are easy to interpret Reliable Results
• Built-in IgG procedural control Highly sensitive and specific
  
  
  

DPP® Syphilis Screen & Confirm
Product Information

Syphilis, caused by the bacterial spirochete Treponema pallidum, is a significant source of human morbidity and mortality worldwide. In fact, it is estimated that there are over 12 million cases of syphilis occurring worldwide every year. In the United States syphilis has a storied history. With an incidence great enough to instigate its own (and one of the earliest) specialized medical journals (American Journal of Syphilis, Gonorrhea and Venereal Disease), syphilis reached its peak incidence in the early 1940’s (approx. 450/100,000 population) and gradually tapered off over the subsequent 60 years, with a small spike in incidence during the late 1980’s. Recently the United States Centers for Disease Control (CDC) estimated an all time low in syphilis incidence in 2000, but more importantly the CDC has seen a steady increase in reported cases since then. Discussion with regards to causative factors of this rise in incidence can be found below.

Given the historical context of syphilis in humans as well the sequelae of pathological features if left untreated (including congenital syphilis of the new born), widespread guidelines have been implemented that take into account both disease progression and epidemiology.

Infection with syphilis leads to one of four clinical scenarios.

Primary Syphilis – Typical presentation is a painless genital lesion that heals spontaneously with 1 to 6 weeks.
Secondary syphilis – Typical presentation is a generalized skin manifestation, such as rash or other lesions that may persist for months.
Latent syphilis – Typically no clinical manifestations.
Tertiary syphilis – Typically occurring in untreated cases that has the potential for a wide range of systemic manifestations effecting a wide range of organ systems such as cardiac, neurologic, skeletal, and skin.

In women, infection with syphilis at any stage can be transmitted to the developing fetus with devastating consequences. For this reason current recommendations state all pregnant women to be screened for antibodies directed against T. pallidum during their first prenatal visit.

Recent data from 2007 epidemiologic studies suggest an overall syphilis incidence of 3.7/100,000 in the U.S. This number represents an overall increase of 12% from recent years and is believed to be concentrated, for the most part, in a subset group representing men who have sex with men (MSM). Extrapolation of this data suggests approximately 70,000 new cases of syphilis occurring in the U.S. annually, with a male:female ratio of 3.5:1.

Syphilis remains a significant global public health problem with the World Health Organization (WHO) estimating 12 million new cases of the disease worldwide each year including 100,000 per year in the United States and 140,000 per year in Western Europe. 

DPP® Screen & Confirm provides the most conclusive evidence, at the point-of-care (POC), of active, untreated disease as compared with current methods, thereby enabling diagnosis and treatment in a single visit to a clinic.

Standard diagnosis of syphilis is currently done using two different laboratory-based serologic tests, namely a non-treponemal screening test, usually either the Rapid Plasma Reagin (RPR) or Venereal Disese Research Laboratory (VDRL), followed by a more specific treponemal confirmatory (EIA) assay.  Chembio has developed the first dual non-treponemal & treponemal POC syphilis test. 

Utilizing Chembio’s patented Dual Path Platform technology, DPP® Screen & Confirm permits the simultaneous yet separate detection of both markers at the point of care. The test, which will be eligible for a CLIA waiver (Clinical Laboratory Improvement Act waiver allows use in point of care settings of simple to use tests), therefore represents a considerable advance in diagnosis as well as in  time to result and ease of use.

Assay Features:

• Convenient  & Cost Effective
• Ideally suited for field and point-of-care testing
• Minimal sample size required—10 µl whole blood, 5 µl serum or plasma
• Room temperature storage
• Long shelf life
• Time & Labor Saving
• Simple, two-step procedure
• Total test time of 15 minutes
• No special equipment required
• Reliable Results
• Built-in IgG procedural control Highly sensitive and specific

• Ideally suited for field and point-of-care testing
• Minimal sample size required—10 µl whole blood, 5 µl serum or plasma
• Room temperature storage
• Long shelf life

• Simple, two-step procedure
• Total test time of 15 minutes
• No special equipment required

• Built-in IgG procedural control
• Highly sensitive and specific

M. bovis bacteria are frequently excreted by infected animals via exhaled air, sputa discharge, feces, milk, urine, and vaginal and uterine discharges, as well as from peripheral lymph nodes. Housing (in contrast to free-range) and zero-grazing may predispose animals to the disease. For example, the highest incidence of bovine TB is routinely observed where intensive dairy production is most common, notably in the milk sheds. Transmission of bovine TB can also occur through animal contact with infected environmental sources such as soil and water.

Many TB-infected free-range wildlife populations may be visibly asymptomatic, showing no obvious clinical symptoms even when lesions are well developed, thus making timely detection problematic. In addition, even though seemingly asymptomatic, these animals are highly contagious. No practical treatment or preventive measures exist for free-ranging wildlife other than relatively ineffective cull practices, while sylvatic reservoir hosts often complicate domestic herd eradication efforts – for example, the ongoing challenges within the United Kingdom concerning TB management in cattle and badger populations.

Numerous methods are available for the detection of animals infected with TB. To date, skin testing remains the only “reliable” test to detect bovine TB. Among these, the CFT (Caudal-Fold Tuberculin Test) is often used as a frontline skin screening TB test. An accredited veterinarian is generally required to perform and read such skin tests. A positive response to the CFT test indicates that the animal has mounted an immune response capable of recognizing M. bovis. The test hasn’t shown to be as specific or sensitive when used on other animal species aside from Bovids, whether free-range or exotic. Skin testing often produces high rates of both false positive and negative results, particularly when the species tested is not bovid. Exposure to other closely related mycobacteria – such as M. avium (avian tuberculosis) and M. paratuberculosis (Johne’s disease) – represent two examples of other mycobacterium species that can yield a false positive CFT test. A false negative CFT response can occur in an animal that is infected with bovine TB but is also co-morbidly infected with another disease that prevents a proper immune response, is in the very early stages of the disease, or in the event of problematic test administration. It is estimated that the false negative rate of the CFT test may be as high as 15%. In other species, the tuberculin skin test is so unreliable that alternative tests are required in order to confirm TB infection.

TB due to either M. tuberculosis or M. bovis has gained increasing recognition as a serious emerging disease of multiple zoo and other exotic wildlife species, as well as in captive wildlife herds (e.g., Cervid species). Tuberculin skin testing has proven to be unreliable or ineffective for most of these species, necessitating reliance on other diagnostic procedures such as the culturing of trunk washings in elephants, which in turn are proving to be similarly insensitive and nonspecific.

Serological assays have shown promise as a diagnostic alternative to skin testing or culture testing for many of these species. Serological blood based TB assays are appealing not only due to better sensitivity and specificity for captive wildlife, exotic zoo species, and other non-traditional livestock, but also because they require only a single handling event, thereby minimizing capture-associated injuries. The serological test concept is simple, rapid, easy to interpret, inexpensive, and is very useful as a slaughter surveillance test or an effective and efficient trap and cull assay.
Chembio Diagnostic Systems, Inc. has developed a family of novel lateral-flow serological tests for TB for non-human primates (PrimaTB STAT-PAK®), white tail deer, reindeer, and elk (CervidTB STAT-PAK®), cattle (BovidTB STAT-PAK®), badgers (BrockTB STAT-PAK®), camels, llamas, and alpacas (CamelidTB STAT-PAK®) and exotic species such as elephants (ElephantTB STAT-PAK®). These tests are all antibody detection assays that employ unique cocktails of carefully selected recombinant antigens of M. bovis and M. tuberculosis. The tests can use serum, plasma, or whole blood samples and yield a result positive or negative result within 20 minutes.
Chembio Diagnostic Systems, Inc.’s family of TB STAT-PAK® veterinary test assays are currently undergoing validation for USDA licensure and market introduction.

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DUAL PATH PLATFORM (DPP)

HUMAN DIAGNOSTICS PRODUCTS

ANIMAL / VETERINARY DIAGNOSTICS PRODUCTS