Hybrid Capture 2 Technology

Hybrid Capture 2 (hc2) technology serves as the platform for QIAGEN’s nucleic acid hybridization assay for detection of human papillomavirus (HPV), Chlamydia trachomatis (CT), and Neisseria gonorrhoea (GC). This diagnostic method allows rapid, standardized testing of genetic material of the infectious agents in virtually any laboratory setting. It employs specific RNA probes, hybridization, antibody capture, and signal amplification that utilizes qualitative chemiluminescent detection.


The digene HPV Test, using Hybrid Capture 2 technology, provides an accurate, cost-effective, user-friendly method by achieving reliable detection without the need for dedicated and isolated lab space, sophisticated laboratory expertise, or concern related to inhibition and contamination.
Benefits of Hybrid Capture:

* Same-day, objective results using a micro-plate test format
* High-throughput automation for handling increasing test volumes
* Minimal required specimen preparation allowing samples to be processed quickly and efficiently
* Less complex workflow than target amplification methods
* Reduced risk of cross-over contamination due to signal amplification instead of target amplification
* Extensive clinical validation data available

hc2 technology superior to PCR methods for HPV DNA testing

For routine HPV diagnostics, it is essential to have a test system at hand which reports clinically relevant results and, hence, can impact clinical decision-making. In contrast to the detection of other infectious disease parameters, a high clinical sensitivity is critical for reliable HPV diagnostics. The hc2 technology fulfills this requirement better than any other method as outlined in multiple clinical validation studies.

In contrast, a high analytical sensitvity as provided by nucleic acid amplification technologies such as PCR is counterproductive for HPV diagnostics as they may detect many transient HPV infections of clinical insignificance. Cervical cancer screening methods require HPV detection correlating to disease and not to the sheer presence of the virus, since 90% of infections is cleared by itself without consequences.

hc2 technology measures sensitivity versus defined clinical endpoints (CIN 3+/SCC) and ensures reporting of positive results only when risk of disease progression exists. QIAGEN’s digene HPV Test has an excellent clinical sensitivity of up to 100% in primary adjunctive screening when combined with a Pap smear test.

* Clinically validated cut-off of 5000 copies/ml
* Proven in extensive multiple trials
* Ensures high negative predictive value

PCR screening can miss severe disease


PCR methods show a high analytical sensitivity with detection limits between 10-400 copies of HPV DNA resulting in detection of clinically irrelevant viral levels as such infections can be cleared off by immune response. Due to viral integration and loss of the targeted regions (L1, E1, E2) or mutation, PCR can miss cases of severe precancer and cancer cases.

* Risk of missing cases of cancer
* Detection of clinically irrelevant viral levels


Hybrid capture (hc2) versus PCR — analytical sensitivity and clinical sensitivity. The analytical sensitivity of hc2 has been adjusted to 5,000 copies of HPV DNA, and the analytical sensitivity of PCR methods can be <10 copies of HPV DNA.
How Hybrid Capture 2 Technology works

The Hybrid Capture 2 System is a signal-amplification assay that uses a technique combining antibody capture and chemiluminescent signal detection. The basic steps of the Hybrid Capture 2 assay are outlined below:

Basic Steps

Clinical specimens are prepared by adding a base solution, which disrupts the virus or bacteria and releases target DNA. Presence or absence of target DNA is read from the results of the chemiluminescent reaction.

Hybridize RNA probe with target DNA Hybrid Capture Signal Amplification

Fig 1: Hybridize RNA probe with target DNA. Target DNA combines with specific RNA probes, creating RNA:DNA hybrids


Fig. 2: Hybrid Capture. RNA:DNA hybrids are captured onto a solid phase coated with universal capture antibodies specific for RNA:DNA hybrids.


Fig. 3: Signal Amplification. Capture RNA:DNA hybrids are detected with multiple antibodies conjugated to alkaline phosphatase. The signal resulting from the chemiluminescent reaction is read and results interpreted.

Doctors call for cancer screens

DUBAI // Doctors have called for a national cervical cancer vaccination and screening programme to catch cases earlier and reduce the rate of the second most common cancer found in women, one that has seen progressively higher incidence in the UAE.

Cervical cancer affects 9.9 women in every 100,000, according to figures by Health Authority Abu Dhabi (HAAD), almost twice the incidence in the broader Middle East, which amounts to nearly five in every 100,000.

It afflicts women at a rate second only to breast cancer, but 70 per cent of cases are diagnosed in the late stages. At that point, only one in three women has a chance of survival. There is no co-ordinated screening programme for cervical cancer in the UAE, as there is in countries where most cases are detected in the early stages.

Dr Saad Aswad is a senior consultant gynaecologist and oncologist – the only specialist of his kind in the UAE – at Tawam Hospital in Al Ain. He compiled a detailed report on a proposed screening programme for cervical cancer drawing on the expertise of more than 40 health professionals and forwarded it to the Ministry of Health in 2004. There has still been no move to implement any of the plans. MoH officials were not available yesterday to comment.

“We need to do something to protect the women,” Dr Aswad said. “Cervical cancer is a cancer we can prevent. Why are we not doing this across the country? If the Ministry of Health introduced it, I think everyone would follow.”

While schoolgirls in Abu Dhabi are offered the Gardasil vaccination for up to Dh50 (US$13.60) for the required three doses, it can cost up to Dh1,900 in Dubai and is not as widely available in other emirates.

Dr Aswad said the preventive vaccine should be available across the whole country.

“We must push for this to be nationwide. It is much easier to implement prevention than cure.”

HAAD said in April it planned to build on a successful pilot vaccination programme in schools and make the vaccine available to all schools in the Emirates.

Last year it vaccinated around 6,000 girls aged 17 and has given another 4,000 the first dose this year. There was a 70 per cent uptake during the pilot scheme. Dr Mawahib al Biate, head of the gynaecology department at the GMC Hospital in Ajman, said a national vaccination programme was needed in the UAE.

“Prevention is always better than the cure,” she said. “A national programme would be a very good idea because of the rates here.” She also said it did not make sense for such an important vaccine to be offered cheaply to some but not others.

In 1998 the MoH reported only eight diagnosed cases of cervical cancer in the country. Last year Tawam Hospital alone saw at least 100 cases, Dr Aswad said.

Recent studies into the efficacy of Gardasil, which was approved by the US Food and Drug Administration in 2006, showed it was effective against the human papillomavirus (HPV) type 16 for an average of eight and a half years. The women in the study, by the University of Washington in the US, were vaccinated in 2001, so more follow-up tests are needed to establish the length of protection. HPV 16 and 18 cause 70 per cent of cervical cancer cases worldwide. Gardasil, made by Merck, is licensed in 109 countries, but some of them find it more difficult to implement a vaccination programme, Dr Aswad said.

Health officials estimate one in 10 women will get an HPV infection in their lifetime, but it is more common in women under 30. Some strains are sexually transmitted, and questions have been asked in some countries about the moral issue of vaccinating young girls.

“Here cervical cancer is increasing out of proportion with the population growth,” Dr Aswad said. “It is time to start protecting the women.”

Dr Ibrahim Abd Elrahman, a consultant gynaecologist and obstetrician at The City Hospital in Dubai, applauded any effort to introduce a national vaccination programme. He saw many women who had never had a Pap smear. “Often I get someone in their late 20s or early 30s who say they have never had one. I organise one with their consent.”

Mitya Underwood

* Last Updated: May 14. 2009 12:14AM UAE / May 13. 2009 8:14PM GMT

Cervical cancer strikes younger women in UAE

By Nina Muslim, Staff Reporter
Published: May 14, 2009, 10:30
http://archive.gulfnews.com/nation/Health/10313458.html

Dubai: Women in the UAE are dying at a younger age from cervical cancer, about ten years younger than the world average of 49, prompting doctors to call for better awareness and prevention.

Dr Sa'ad Gazzal Aswad, head of obstetrics and gynecology at Tawam Hospital said at a press conference on Wednesday that he was seeing more and more women between the age of 35 and 40, instead of 50 a decade ago.

"I don't know why; we will have to study more. But the point is that it affects young women of childbearing age with children, leaving (the children) when they die," he told Gulf News later.

"The impact is really sad. I had a 32-year old patient who died and she had nine children, the youngest is 2. The cancer affects not just the person but the whole family," he said.

He added the patient, like more than 70 per cent of all cases he has been receiving, was referred to him when her cancer was already considered advanced and had a lower rate of survival. According to Tawam Hospital records, about 100 cases of cervical cancer were recorded last year.

Furthermore, more women in their 20s were presenting with abnormal pap smears, or pre-cancerous lesions.

Cervical cancer is caused by strains 16 and 18 of the Human Papilloma Virus (HPV), which is the same virus (but different strain) that causes genital warts. It is transmitted through sexual contact, which does not necessarily involve sexual intercourse. There are two vaccines available to prevent the cancer, but only one is approved by the US Food and Drug Administration.

Dr Wissam Haddadin, franchise manager of the cervical cancer vaccine Gardasil, produced by Merck, Sharpe and Dohme, said more awareness and prevention were needed to stop the preventable disease from striking women down.

"Some people don't realise (in cervical cancer's case) there is a causative agent," she said.

She added prevention and awareness in the region was very low, saying a 2006 informal survey the company conducted found about 20 per cent of women questioned knew what a pap smear was and only 9 per cent did it.

Pap smear is a screening procedure, in which a cell scraping is taken from the cervix and examined for pre-cancerous lesions.

Some screening programmes are taking place, including at primary healthcare centres under the Ministry of Health. Private medical centres also offer the service. However, there is no comprehensive and uniform policy in place to ensure all women in the UAE are being screened for the cancer.

Do you have regular checkups? Do people avoid being checked for fear of having an illness? Do you know of anyone who had successfully battled cancer due to early detection?
Your comments

The article has definitely created awareness about cervical cancer. More information regarding symptoms, causes and cures would help readers understand the disease better. Also at what age must a woman get herself tested and details could help women to have regular checkups. Generally people avoid checkups either because they are very busy in their family life, they feel fit or they have a fear of having an illness. Women (especially working women) lead a hectic life and have no time for themselves. My cousin?s wife (age 37) was diagnosed with breast cancer last year. She underwent mastectomy and then chemotherapy and radiation and now is leading an almost normal life. She feels weak at times and does not have the energy she had before the illness. Cancer is a killer disease and fighting it is possible if detected in the early stages. Awareness about the disease and its various forms must be spread so that people will not hesitate to go for required tests. Regular exercise and a healthy diet could ward off most diseases. A regular checkup even if a person is perfectly fine and healthy is necessary.
Naina Nair
Sharjah,UAE
Posted: May 14, 2009, 17:23

Doctors should advise the women to do this Pap smear test and should encourage them to do it, there is no harm if the doctor will tell his patient to do this check up test, I told my wife to do a full check up and they didn't even tell her about this test.
Samer K.
Dubai,UAE
Posted: May 14, 2009, 17:20

I had been experiencing abnormalities in my menstrual cycle. When I came to Dubai, I decided to visit an OB/Gynaecologist for a check up. I found out that a year after giving birth, I must have a pap test and also that the doctor discovered some infection. And she told me that if I had taken long to seek doctor's advice, it could lead to cervical cancer. So, that is when I realised that a single infection that I didn't mind for a long time could worsen my health. So, now, I do my pap test every year to check the condition of my cervix. It is good for women to be aware and please do not be ashamed of this kind of situation. Doctors are here to understand us and to help us prevent the sickness. Always remember that Prevention is better that CURE.
Mhadzie
Dubai,UAE
Posted: May 14, 2009, 11:44

I am a mother and know how preoccupied my lot is with looking after our young children and families. Most mothers are so busy attending to the needs of the rest of the family members that they hardly have ANY time left for themselves. This lack of time for oneself often does take quite a toll on the mothers. I sincerely appreciate such eye-opening articles by Gulf News. Please continue the good work.
Shiuli Dutt Dey
Dubai,UAE
Posted: May 14, 2009, 11:43

the issue is that most of these tests are not even covered by insurance so unfortunatly people think about the financial aspect. Insurance should cover one test on a regular basis, this would also save them money when curing at an early stage instead of big expenses at a late stage.
From A Reader
Abu Dhabi,UAE
Posted: May 14, 2009, 11:00

There definitely should be more awareness about Cervical cancer, since it is becoming very common among women at a very early age.The worst thing about this cancer is that it is diagnosed at 3rd or 4th stage and it becomes too late to save the patient then. I would like to urge every woman to educate themselves by reading about cervical cancer and to take precautionary measures in advance. Also, it is important to spread the awareness about the disease among my friends and family. Being 23 years old, I would like to get preventive vaccination for the same. I would like to know about hospitals and clinics which would conduct the necessary test. I think the authorities should take measures to spread the awareness among women. Many people haven't even heard about this disease.
Zahrah
Dubai,UAE

How do I talk to my partner about HPV?

You and your partner may benefit from talking openly about HPV. You can tell your partner that:

* HPV is very common. It can infect the genital areas of both men and women. It usually has no signs or symptoms and goes away on its own.
* Most sexually active people get HPV at some time in their lives, though most will never know it. Even people with only one lifetime sex partner can get HPV, if their partner had it.
* There is no test yet for men to find out if they have HPV. But the most common health problem caused by HPV in men is genital warts. The type of HPV found on your HPV test can cause cervical cancer in women; it does not cause genital warts.
* Partners who have been together for a while tend to share HPV. This means that your partner likely has HPV already, even though your partner may have no signs or symptoms.
* Having HPV does not mean that you or your partner is having sex outside of your relationship. There is no sure way to know when you got HPV or who gave it to you. A person can have HPV for many years before it is found.

If your sex partner is female, you should talk to her about the link between HPV and cervical cancer, and encourage her to get a Pap test to screen for cervical cancer.
Common Questions about HPV
Is there a treatment for HPV or abnormal cells?

There is no treatment for HPV (a virus). But there are treatments for abnormal cervical cells, which can be killed or removed. Treating abnormal cells will stop them from growing into cancer. But it may not remove the virus (HPV). That’s why it’s important to go back to your doctor as told, to make sure abnormal cells do not grow back. You may need to get Pap tests more often for a while. But most people do eventually fight the virus off.
Does having HPV or abnormal cervical cells affect my chances of getting pregnant or having healthy babies?

Having HPV or cell changes on your cervix does not make it harder to get or stay pregnant. The type of HPV that is linked to cancer should not affect the health of your future babies. But if you need treatment for your cell changes, the treatment could affect your chance of having babies, in rare cases. If you need treatment, ask your doctor if the treatment can affect your ability to get pregnant or have a normal delivery.
couple Will I pass HPV to my current partner?

If you have been with your partner for a while, your partner likely has HPV too. But your partner likely has no signs or symptoms of HPV. Partners usually share HPV, until your bodies fight it off naturally. There is no way to know if your partner gave you HPV, or if you gave HPV to your partner.
Can I prevent passing HPV to a new partner?

Condoms may lower your chances of passing HPV to your new partner, if used all the time and the right way. But HPV can infect areas that are not covered by a condom—so condoms may not fully protect against HPV. The only sure way to prevent passing HPV to a new partner is to not have sex.