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Innovative Tuberculosis Diagnostics

TB: A Global Threat

Tuberculosis (TB) is a life-threatening infectious disease caused by microbes named Mycobacterium tuberculosis, which most commonly affects the lungs. It is transmitted from person to person via droplets from the throat and lungs of people with the active TB disease. More than 2 billion people – one third of the world' s population – are infected with TB bacilli and one in every 10 of those people will become sick with active TB in his or her lifetime. TB inflicts people in developing countries  with higher rates of incidence, drug-resistance and mortality. People living with HIV are at a much greater risk. To better combat TB and curb its spread, giving accurate diagnose and improving the detection rate in early stage of the disease is a critical task for healthcare professionals.

Disease Facts

  • 8.6 million new TB cases were reported in 2012, including 1.1 million cases with HIV co-infection;

  • In 2012, 1.3 million people died from TB, including 430,000 people living with HIV;

  • TB is one of leading causes of death in females causing 410,000 female mortalities in 2012;

  • TB morbidity has decreased by 45% since 1990;

  • TB/HIV co-infection:

- An estimated 1.3 million lives were saved globally between 2005 and 2011 by implementing collaborative TB/HIV activities;

- Globally, 48% of the TB patients known to be living with HIV in 2011 were started on antiretroviral therapy (ART).

  • l  Multidrug-resistant TB (MDR-TB)

   -  In 2012, a total of 94,000 TB patients eligible for MDR-TB treatment were detected. More than half of these cases were in India, China and the Russian Federation;

   - The number of MDR-TB cases identified in the 22 high MDR-TB burden countries doubled between 2009 and 2012, and reached about 83,715 worldwide. Only 28% of the estimated MDR-TB cases were diagnosed.

TB High burden countries

The 22 high TB burden countries accounts for 80% of the tuberculosis cases in the world, including:Afghanistan, Bangladesh, Brazil, Cambodia, China, Democratic Republic of Congo, Ethiopia, India, Indonesia, Kenya, Mozambique, Myanmar, Nigeria, Pakistan, Philippines, Russian Federation,  South Africa, United Republic of Tanzania, Thailand, Uganda, Viet Nam, Zimbabwe, More info of TB

   The map of the TB High burden countries

Laboratory TB Diagnostics

    AFB Smear: Acid Fast Bacilli (AFB) smear is a method to directly observe existence of Mycobacterium Tuberculosis under a microscope when sputum specimen from suspected patient is smeared on a glass slide and stained.  It is a commonly-used method for screening infectious pulmonary TB cases. The advantages of FAB include quickness and low-cost, however, the low detection rate- less than 30% for sputum specimens from clinically diagnosed or suspected patients-is a major defect causing detection failure in some positive specimens and lost opportunities for early proper medication treatment.
     Culture: This is a micro-bacterial method to inoculate specimen on cultural base and observe whether suspected bacteria grows over time. A widely-used solid cultural-base for TB detection is Lowenstain-Jensen or L-J recommended by International Union Against Tuberculosis and Lung Disease (IUATLD). Culture is sensitive; however, the method involves complex procedures and, due to the long growth cycle of TB, takes weeks for result.  The automated liquid-cultural systems e.g. BacT/ALERT 3D and BACTEC 960 System provide better testing performance and is regarded as "gold standard" for tuberculosis pathogen diagnosis. These systems reduce the length of testing time to a week, yet it requires investment on expensive equipment by the users.
     Immunological Testing: The immunology testing employs a biological process called immunological reaction of which the antigen from the pathogen binds with the specific antibody to produce readable signals.  The available immunological TB testing includes rapid test which uses serum or peripheral whole blood as specimen. The method is quick and low-cost.  Result can normally be optically read in the test card in about 15 minutes. However, the sensitivity and specificity remain to be improved. It is mainly used as an auxiliary laboratory testing.
     PCR-based Testing: PCR is the most widely used nucleic acid amplification technology in pathogen diagnosis. But normal PCR is prone to laboratory cross-contamination and subsequent false positive.  Later appeared florescence quantitative PCR technology technically resolves contamination problem by sealing off the reaction space, however, it depends on intricate and expensive equipment and special laboratory, preventing it from wide application in low-resource setting.

EasyNAT® TB Diagnostic Kit

EasyNAT® Diagnostic Kit for Mycobacterium tuberculosis Complex (MTBC) DNA(Isothermal Amplification - Lateral Flow) is developed on Ustar's novel microbe detection platform which integrates CPA amplification technology and disposable, contamination-proof DNA detection device. The testing involves three steps: Step1, Liquifiy sputum and extract DNA to produce an amplification template and add it into in a 0.2 ml Eppendorff tube containing the CPA reagents; Step 2, Put the tube into an heat block maintaining 63℃ for one-hour for isothermal amplification, Step 3, Insert the amplified tube into the Ustar disposable DNA detection device for qualitative read-out in 15 minutes. The turn-around time is about 3 hours. The whole amplification and DNA detection process takes place in a sealed-off condition thus preventing cross-contamination. EasyNAT® TB detects as low level as 10 pathogens per 1 ml.  It is fast, easy-to-use, and requires no costly qPCR machine and PCR infrastructure, thus useful in different levels of clinical institutions, especially as a point-of-care testing in low-resource setting.  Ustar's isothermal nucleic acid amplification system for tuberculosis diagnosis was selected and recommended by World Health Organization (WHO) in 2010.

Q & A

Q1: How EasyNAT®  TB kit helps better diagnose TB ?

EasyNAT®  TB kit is designed as a screening tool for active pulmonary TB  to replace sputum AFB Smear Microscopy as to improve the detection rate in people with suspected TB infection. AFB Smear has been widely-used as a quick and low-cost method for screening active pulmonary TB,  however, its detection rate is normally lower than 30%, causing diagnose failure and loss of best treatment opportunities. In a large clinical trial at 4 county-level TB hospitials in China (n=2,200), EasyNAT® TB is proved to have high sensitivity and specificity compared with L-J solid media culture while reduce turn-around time from 54 days to just 4-5 hours.  It is simple and easy to use, requiring only basic lab infrastructure, hence particularly useful in low-resource setting in developing countries. 

 Q2: How about the testing performance of EasyNAT® TB kit ?

Clinical evaluation indicates that NATeasy™has similar sensitivity compared to BacT/Alert 3D fast liquid culture with high specificity and better sensitivity than L-J solid culture and AFB smear.
In a clinical evaluation conducted at Shanghai Centers for Disease Control from March to June of 2008, sputum specimens from 180 persons suspected of having TB based on their clinical symptoms and presentation and from 98 non-TB patients with lung cancer, lung edema, and other pulmonary illnesses presenting at the same hospitals were collected. For comparison with NATeasy™all of collectedspecimens were also processed for AFB smear, L-J solid medium and BacT/Alert 3D liquid culture. The detection rates of mycobacteria in 180 specimens was 50.6 % (91/180), 36.1% (65/180) and 38.9% (70/180) and 53.9% (97/180) by NATeasy™, AFB, L-J culture and BacT/Alert 3D liquid culturerespectively.  NATeasy™ sensitivity for smear negative and liquid culture positive specimens was 96.9%. The specificity of NATeasy™in culture negative specimens was 98.8%.
Besides, NATeasy™ had also been sent for verification testing at China National Institute for Controls of Pharmaceutical and Biological Products, NICPBP) in Beijing in 2008. NATeasy™ passed national reference panel with lowest detection level of 10 bac. copy/ml. 

Q3: Who is supposed to use EasyNAT® kit?

EasyNAT® TB testing kit is meant for use in different levels of hospitals or clinics where patients with TB-like symptoms first visit. It is especially useful in low-resources setting due to its features of simple and easy-to-use as well as equipment-free. In addition, the glassified CPA reagent meant for ambient temperature delivery enables it applicable even in remote area where machine-based laboratory is impossible. However, it is also applicable in big hospitals due to its significant benefits of quickness that culture is far from achievable. In this sense, NATeasy™ Isothermal TB testing kit provides TB professionals with a choice of first-line testing in addition to AFB Smear.

 

Q4: What is the package and testing cost of EasyNAT® ? 

EasyNAT®Isothermal Amplification TB Detection Kit composes of a CPA reagent kit and a disposable cross-contamination-free DNA amplicon detection device kit, both in 20 tests package. We provide reagents in liquid form or glassified form upon customers' need. The testing cost per test is similar to that of RT-PCT test but the initial investment on expensive equipment is saved.

 

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