False Positives Vs False Negatives
Because STI tests arent perfect, people who design them often have to choose whether its better to have more false-positive or more false-negative results. Which is better depends on the severity of the disease and the healthcare providers ability to treat it.
Imagine, for example, that a condition has no serious long-term consequences but the treatment itself is grueling. In such cases, a false positive is worse than a false negative because it may expose a person to needless treatments that cause more harm than good.
On the other hand, if an infection is serious and requires immediate treatment, the test would need to be highly sensitive to avoid a false-negative result. Doing so can lead to a missed diagnosis. One such example is an HIV test.
Performance Evaluation Of A New Rapid Urine Test For Chlamydia In Men: Prospective Cohort Study
- Accepted 17 February 2009
Quick Chlamydia Urine Test Accurate In Men
2 Min Read
CHICAGO – A rapid urine test for chlamydia identified 84 percent of infections in men, offering a quick and painless way to diagnose the common sexually transmitted disease, British researchers said on Tuesday.
They said a study of the test among 1,200 men, published in the British Medical Journal, offers hope for on-the-spot treatment.
This new test is both accurate and swift, allowing men attending the clinics to be tested and treated on site in one visit, Dr. Helen Lee from the University of Cambridge, who developed the test, said in a statement.
Lee is also president and chief executive of Diagnostics for the Real World in Sunnyvale, California, a university spin-off company that is commercializing the test.
Chlamydia is the most common sexually transmitted disease among women and, in 70 percent of cases, causes no symptoms. The bacterial infection can lead to pelvic inflammatory disease, ectopic pregnancy and infertility.
It can also make a woman more likely to be infected with or to pass on the AIDS virus.
Once diagnosed, chlamydia can be easily treated with antibiotics, but it often goes undiagnosed.
Rapid tests for the infection in men have been relatively inaccurate and uncomfortable, requiring a painful swab of the urethra, the team said.
Horror stories about painful swabs have put men off getting tested for chlamydia, and other non-invasive tests are expensive, technically complex and take days to obtain the result, Lee said.
Editing by Maggie Fox
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Do Regular Sti Tests Include Herpes
No. If you dont have symptoms, STI testing includes gonorrhea, chlamydia, HIV and syphilis, and only involves time with a medical assistant. The Centers for Disease Control does not recommend herpes testing for people without symptoms.
If you think youve been exposed to herpes, but you arent showing symptoms, make sure to tell your health care provider prior to getting tested. At Planned Parenthood, herpes testing requires a visit with the nurse practitioner.
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How Accurate Is A Urine Test
The accuracy of a urine test to detect STD has always been questioned. When we talk about undergoing a test for STDs we do find that there are a number of methods that are in use. Each of it offers its own pros and cons. A urine test is the most preferred as it is simple and does provide accurate results, which again are dependent on the window period.
Urine tests provide accurate results when the disease causing bacteria is present in the urine samples of the patient. But, when there is an infection and the bacteria are not present in the urethra, a urine test cannot detect the same. So, when a urine test is conducted within the window period, the result might not be accurate but when it is conducted after the window period, the test results can be accurate. Other than urine tests, even normal blood tests show STDs if the condition is in a progressive stage.
If you are undergoing a urine test for STD accuracy, it also helps to go in for a second test like Swab Test as it helps to confirm the existence or non-existence of STD. Remember that a wrong analysis can often lead to medical as well as personal consequences.
What Is The Purpose Of Urinalysis
There are several reasons why a doctor or medical professional will recommend a urine test. Many disorders can be diagnosed in their early stages by detecting abnormalities in the urine. These abnormalities include increased concentrations of constituents that are not usually found in significant quantities in the urine, such as:
Sbus Appraisal Of The Evidence
- Urine specimens are somewhat less sensitive than vaginal and cervical specimens. Vaginal specimens have the highest sensitivity for diagnosing chlamydia in women.
- Urine, vaginal, and cervical specimens have similar specificity. In other words, they are equally likely to yield a correct, ie, negative, finding in women who are not infected.
- The scientific evidence is insufficient to compare the diagnostic accuracy of urine specimens alone versus various combinations of specimens, since only one study in the assessment included such a comparison.
- The scientific evidence is insufficient to draw conclusions on the cost-effectiveness of using urine specimens as the only test for establishing a chlamydia diagnosis in women. Too few studies of sufficient quality are available. The total cost of chlamydia testing is influenced mainly by how specimens are taken. Vaginal and urine specimens can be collected by the patient herself. This lowers the cost in comparison to taking cervical specimens, where health professionals must collect the specimen.
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How Much Does The Test Cost
The cost of chlamydia testing varies based on many factors. Chlamydia testing may be paid for by health insurance when ordered by a doctor. Because health plans vary, its important for patients to discuss the cost of testing, including any copays or deductibles, with their health plan.
For patients without health insurance coverage, the cost of testing may include the cost of the office visit and sample collection as well as technician fees. Testing may also be available for free or at low cost through community-based organizations and local health departments.
Swab Method If You Have A Penis
You will be asked to remove your pants and underwear and cover with a paper blanket. You may be asked to sit on an exam table.
A medical professional will swab the head of your penis with alcohol or another sterile agent. Next, theyll insert a cotton swab into your urethra at the tip of your penis.
The medical professional may also use a swab or very small brush to gently rub your anus, inside your mouth and throat, or both.
If more than one sample is taken, a new, clean swab will be used for each sample. The swabs are sent to the lab for testing to determine if chlamydia trachomatis bacteria is present.
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Sensitivity & Specificity Of The Test
Definition: Sensitivity is the ability of a test to identify patients that have the disease.
So if 10 people have a disease and eight of ten of those patients as being positive. Then those are true positives. Sensitivity then is 80%. Rest two of those patients, however, are going to be negative, even though they have the disease and those are called false negatives.
So when a test that is highly sensitive is good for ruling out disease, when the test is negative .
Definition:Specificity of the test, is its ability to identify those without the disease.
10 people dont have any disease. So if 7 out of 10 patients have been tested negative because they dont have the disease and it didnt show in the test as well. So those are truly negative and the Specificity of the test is 70%. So, 3 of them have been indicated as positive, even though they dont have the disease. Those are referred to as False positive.
So when the test is specific is good at ruling in the disease when test positive
How To Get Tested
Chlamydia testing is usually ordered by a doctor. In people without symptoms, a doctor can evaluate their risk and suggest an appropriate screening schedule. If a patient has symptoms of this infection, a doctor will order testing to diagnose or rule out chlamydia.
Testing for chlamydia can be conducted at a hospital, doctors office, health clinic, or community health program.
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How Does A Doctor Test For Stds
What procedure will a clinician follow in testing someone for STIs?
It depends on the infection. When health care providers test for sexually transmitted infections, they usually test for a few different ones. To decide what to test for, providers examine their clients. They talk with them about their visible symptoms, other symptoms they may feel, and what kind of risks they may have taken.
Depending on whats found during the examination and conversation, the health care provider may take samples of
- blood to check for CMV , hepatitis, herpes, HIV, or syphilis
- urine to check for chlamydia and gonorrhea
- cells to check for BV , chlamydia, gonorrhea, HPV , molluscum contagiosum, or scabies
- fluid, secretions, or discharge to check for BV, gonorrhea, herpes, HPV, pelvic inflammatory disease, syphilis, or trichomoniasis
- cells from the cervix for Pap tests to detect changes associated with certain types of HPV that can cause cancer
- saliva can be used to test for HIV
Recently, some health officials have called for similar tests on cells collected from the rectum if people have anal sex.
Most health care providers will not do a screening for sexually transmitted infections unless the client asks. So, dont let embarrassment become a health risk. If youre sexually active, you should ask to be screened for infections.
Chlamydia Can Be Treated And Cured With Antibiotics
Individuals diagnosed with chlamydia should abstain from sexual activity for one week after finishing antibiotics. Keep in mind that it is possible to become reinfected with chlamydia after receiving treatment. This is why it is crucial for partners of those who have chlamydia to also get tested and treated if found positive. Chlamydia often occurs along with gonorrhea . If you have one of these STDs, you might have the other because the risk factors and symptoms are very similar. Getting tested for both is important.
Whether or not symptoms are present, testing or screening for chlamydia can be done as early as 24 hours after exposure. The incubation times vary from person-to-person for the most accurate results, get tested two weeks after initial exposure. If you test positive for chlamydia, it is advised to get retested two weeks after completing treatment to be sure that all of the Chlamydia trachomatis bacteria is cleared from your system.
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Can I Take The Test At Home
Tests are available to detect chlamydia at home. Most at-home chlamydia tests are self-collection kits, which allow you to obtain a swab or sample of urine at home and return it to a laboratory by mail. If an at-home chlamydia test returns positive results, a doctor may suggest confirmation testing with a laboratory-based method.
Appendix: Key Questions Reviewed By The Work Group And Member Responsible For Literature Summary
- Does the sensitivity and specificity of available tests for C. trachomatis and N. gonorrhoeae vary with respect to anatomic site from which the specimen was collected and/or specimen type?
- Joan Chow, DrPH, California Department of Public Health, Richmond, California
- Katherine Whitaker, PhD, Food and Drug Administration, Rockville, Maryland
- What specimen types are optimal for of C. trachomatis and N. gonorrhoeae screening purposes?
- Charlotte Gaydos, DrPH, Johns Hopkins University, Baltimore, Maryland
- Sarah Guerry, MD, Los Angeles County Department of Health Services, Los Angeles, California
- Barbara Van Der Pol, PhD, Indiana University School of Public Health, Bloomington, Indiana
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What Happens During A Chlamydia Test
To do a chlamydia test, you will need to provide a sample of fluid from the part of your body that may be infected. There are two ways to gather the sample:
- A first-catch urine sample. You use a sterile cup to a collect urine from the very first part of your urine stream. To get an accurate test result, you will need to stop urinating for two hours before the test.
- A swab sample. Your provider will use a special swab or brush to gather cells, usually from the genital area . This may cause some brief discomfort. In certain cases, the rectum, cervix, throat, or eyes may be swabbed. Your provider may give you the option to swab yourself following special instructions.
Test results are usually ready in a day. There are some rapid chlamydia tests that can provide results in 90 minutes or less.
You can also buy at-home collection kits to test for chlamydia and other STDs. With these kits, you collect a swab or urine sample at home and send it to a lab for testing. It’s important to follow all the instructions carefully.
You should not use an at-home test if you have symptoms of chlamydia or if your partner has chlamydia. In that case, it’s important to talk with your provider right away so you don’t delay treatment.
Ask your provider whether at-home chlamydia testing is right for you.
How Do You Test For Chlamydia
Nucleic Acid Amplification The three NAA tests described below work by finding the DNA of chlamydia bacteria. Because NAA tests search for the bacterias genetic material, it is very unlikely that a false-positive test result will occur. The incubation period for chlamydia is 1-5 days, so wait at least five days after potential chlamydia exposure before getting tested to ensure the most accurate results possible.
- Testing via urine samples needs to consist of first-catch urine . Patients should not include more than the first-catch in the collection cup to avoid diluting the sample.
- Patients should not urinate for at least one hour prior to providing a sample.
- Female patients should not cleanse the labial area prior to providing the specimen.
Why shouldnt you get tested for chlamydia via a blood test?
Enzyme-linked immunosorbent assay Antibodies, IgM
- IgM antibodies are found mainly in the blood and lymph fluid they are the first antibody to be made by the body to fight a new infection.
- This blood samples results should not be used as a diagnostic procedure without confirmation of the diagnosis by another medically established diagnostic product or procedure.
Enzyme immunoassay Antibodies, IgG
- IgG antibodies are the most abundant type of antibody they are found in all body fluids and protect against bacterial and viral infections.
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Testing With Polymerase Chain Reaction And Transcription Mediated Amplification
The performance of the Chlamydia Rapid Test was assessed to meet the requirements for Conformité Européenne licensure, which stipulate that the comparator test should be a state of the art assay and should be performed with specimens approved for the test. Polymerase chain reaction testing for chlamydia, which is licensed for urine specimens, was chosen as the ideal standard test for the study. The Roche Amplicor CT/NG polymerase chain reaction assay has undergone comprehensive evaluations with male urine samples and is similar in reliability to other nucleic acid amplification methods for detection of C trachomatis in urine.13
Urine specimens were sent to a laboratory accredited by the Clinical Pathology Accreditation for C trachomatis testing with the Amplicor CT/NG polymerase chain reaction assay according to manufacturers instructions . Samples that yielded discordant results with the Chlamydia Rapid Test and the polymerase chain reaction assay were tested with the mono-specific Aptima CT kit, a transcription mediated amplification assay according to manufacturers instructions at the Sexually Transmitted Bacteria Reference Laboratory . In addition, 100 randomly selected specimens negative with polymerase chain reaction and 20 concordant positive samples were masked and tested by this latter assay to minimise potential bias introduced by testing discordant samples only.
True Care Is Here For You
As an added benefit to no-cost pregnancy testing at True Care, we include STD/STI screening and treatment for chlamydia, gonorrhea, and trichomoniasis. Abortion is an invasive procedure so its important to know beforehand if you have an STI. If left untreated, the infection could spread.
The only way to ensure you do not contract an STI/STD is to practice abstinence. Another way to prevent contracting STIs is by remaining in a long-term, monogamous relationship like marriage. Any time you do have a new sexual partner, you should make sure you both get tested beforehand.
Take care of your sexual health by making an appointment today for no-cost pregnancy testing including no-cost testing and treatment for chlamydia, gonorrhea, and trichomoniasis. We promise youll receive judgment-free and compassionate care.
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