PASS or FAIL? The Home Testing Equation
or
A Home Testing Primer

August 15, 1997

Media Contacts: Sarah Goodwin, 404/727-3366 - sgoodwi@emory.edu
Kathi Ovnic, 404/727-9371 - covnic@emory.edu
http://www.emory.edu/WHSC/

A rash of Food and Drug Administration (FDA) approvals and improved technology has enhanced the ability of health care consumers to test themselves at home for an increasing number of medical conditions.

This is good news. Convenient and affordable home tests give consumers greater awareness and control over their health status.

Without leaving home, consumers can now learn their HIV status, the best time to conceive, blood clotting ability and even presence of illicit drugs. Advancements continue to be made for in-home tests for pregnancy, blood pressure, blood sugar, cholesterol, markers for colorectal cancer and some gynecologic cancers and presence of a potentially blinding disease called macular degeneration.

The following is a primer of some of the most popular in-home tests now on the market.

HIV

Over-the-counter HIV home test systems have been available for more than a year. They retail for about $60. The systems allow the buyer to take a blood sample at home, send it to a designated laboratory for HIV-1 antibody testing, and call anonymously using a precoded identification number to learn test results.

The buyer is asked to read a pre-test counseling booklet about HIV and AIDS then send a blood sample taken from a finger stick to a designated laboratory. About one week after mailing the test card to the laboratory, consumers may call for results by identifying themselves with the precoded number. Negative results are given by prerecorded message which also outlines the one-month window during which an HIV+ person may test negative. Professional counselors personally speak to callers about positive or inconclusive results. Referrals to local medical resources are provided if needed.

Experts hope the convenience and confidentiality afforded by home HIV testing will encourage more at-risk persons to seek their HIV status. The Centers for Disease Control and Prevention has estimated that more than 60 percent of Americans at risk for contracting HIV have not been tested.

OVULATION

Over-the-counter urine kits help women determine the most fertile days of their menstrual cycle. The tests measure surges i wish to become pregnant and whose only form of contraception is abstaining from sex during ovulation, Dr. Murphy says. "However, we do not recommend use of the kit for this purpose."

The tests are about $60 and require that women test their urine in much the same method used for home pregnancy tests. A dark spot on a test strip exposed to the urine indicates the hormone surge has occurred and ovulation will occur within a day.

For women wishing to become pregnant, the test indicates the most optimal time for intercourse, usually the five days prior to ovulation and the day of ovulation itself. According to reproductive medicine specialist Ana Murphy, M.D., of The Emory Clinic Perimeter, home LH tests are better predictors of ovulation than charting basal body temperature.

"Although much cheaper, it is much more difficult to predict ovulation with temperatures, says Dr. Murphy, who also directs the Emory Center for Reproductive Medicine and Fertility. "Once the temperature goes up, ovulation has already occurred. Patients with irregular cycles find the ovulation kit more cumbersome and expensive because they may need to test for longer periods of time and therefore may need to use more than one kit."

BLOOD CLOTTING

The FDA approved in March the first home test for blood coagulation. The prothrombin time (PT) test helps heart patients and others who are taking the "blood thinning" drug warfarin (Coumadin) determine whether the effect of the drug is within the therapeutic range. Patients draw a small of amount of blood using a finger stick test then run the sample through a hand-held electronic device. Results are displayed on the device's screen. The system can store results of up to 40 tests, providing the patient's doctor valuable data for making dosing recommendations.

"Blood thinners" (anticoagulants) are often prescribed to persons with artificial heart valves, irregular heart beats or other conditions associated with tendency to blood clotting. But anticoagulants are risky and must be closely monitored says Emory Heart Center cardiologist Arturo Corso, M.D., of The Emory Clinic Smyrna. If the drug level is too high, patients are at risk for hemorrhage; if too low, patients are at risk for developing blood clots that may obstruct blood vessels and cause strokes or even death.

The home test currently is only available for the blood thinning effect of warfarin, though studies are being conducted on other anticoagulants. It is available via prescription for home use under a doctor's supervision.

DRUGS OF ABUSE

The first over-the-counter test for illicit drugs was approved by the FDA in January. The test is able to detect in urine the presence of marijuana, PCP, amphetamines, cocaine, heroin, codeine and morphine. Urine samples collected at home are sent to a special laboratory for extensive testing. Test results may be obtained by calling a toll-free number and using an anonymous identification number supplied in the kit. Counselors carefully explain tests results, including false positives and negatives, and will make referrals for drug abuse counseling or medical treatment.

PREGNANCY

When performed correctly, home pregnancy tests are about 95-100 percent accurate, says Richard White, M.D., a gynecologist and obstetrician at The Emory Clinic Perimeter.

Most tests ask users to test first morning urine on the first day after a missed period. The best tests require the least number of steps, says Dr. White, and display "error indicator" signals.

False negative results may occur if insufficient time has elapsed since conception, reading results before the allotted time or excessive shaking of the urine sample. If the test reads negative after instructions were carefully followed, manufacturers usually recommend users wait a specified number of days before retesting. A positive results is usually a sure indication of pregnancy -- and time see a health professional for confirmation and prenatal care.

HIGH BLOOD PRESSURE

The same mercury or aneroid sphygmomanometers used in conjunction with stethoscopes by health professionals to gauge blood pressure are available to the consumer to test ones' own blood pressure. The devices are highly accurate, but may be a challenge to the untrained. The automated electronic or digital meters also available are much simpler to use, says internist Warren Davis, M.D., of The Emory Clinic Perimeter, and still serve the purpose of allowing patients to monitor any significant changes in their own blood pressure. Most blood pressure monitors require "recalibration" at least once a year by a trained technician.

DIABETES

Many persons with diabetes are encouraged by their doctors to monitor their own blood glucose levels between office visits. Blood glucose tests are more accurate than urine glucose tests, says internist/endocrinologist William Domin, M.D., of The Emory Clinic Smyrna, and they provide users instant data on current glucose levels. After collecting a sample of blood from a finger stick and placing it on a test strip, the user either compares the color that develops on the strip with a chart or, depending on the kit, feeds the strip into a small machine that provides a blood glucose range. Some meters store test results for later review by one's doctor.

The American Diabetes Association (ADA) cites several factors than may lead to less precise readings, including a dirty meter, one not at room temperature, an outdated test strip or a meter not calibrated for the users particular choice in test strips. Dr. Domin says results may skewed if insufficient blood is collected on the strip. The ADA suggests testing one's measurement skills by taking one's own meter to the doctor's office and conducting a test there after the physician's staff has conducted its own blood test. Another type of urine test which measures ketones may be recommended should one's diabetes get out of control.

CHOLESTEROL

The cholesterol home test currently on the market provides instant information on one's total blood cholesterol level, but does not distinguish between low-density lipoprotein (LDL -- the "bad" cholesterol) and high-density lipoprotein (HDL -- the "good" cholesterol), says family practitioner William J. Arban, M.D., of The Emory Clinic Fayetteville. He believes getting a full lipid profile which provides an LDL/HDL ratio and triglyceride count is necessary, since recent studies point to LDL and HDL as separate risk factors for coronary artery disease. A kit is currently undergoing testing for possible FDA approval that would provide an LDL/HDL ratio, though test results would not be instantaneous; buyers would have to send blood samples to a lab for analysis.

COLORECTAL CANCER

Cancer and other disorders of the colon or rectum may be detected by testing for the presence of blood on the outside of stool. Home fecal occult blood tests are available that detect excreted blood. A test strip dipped into toilet water after a bowel movement changes to certain colors if exposed to blood.

"Colorectal is one of the most common of all cancers -- and one of the most easily detected by home testing or regular colonoscopies conducted by a physician," says internist Gary D. Vogin, M.D., of The Emory Clinic Perimeter. "When detected early, prognosis is usually good. After age 50, all persons should regularly check for colorectal cancer."

GYNECOLOGIC CANCERS

An in-home kit is available that allows women to perform their own vaginal self-exams. Kits include a plastic speculum, lubricant and mirror that clips on to a light. The kits are purported to help women detect external vaginal diseases such as vulvar cancer or signs of sexually transmitted diseases such as the vaginal warts associated with human papilloma virus (HPV). Manufacturers suggest women may also use the kits to detect internal discoloration that may signal cervical cancer.

"Any woman can check her vulva/outer vagina with a mirror and light," says obstetrician/ gynecologist Mary Dolan, M.D., of The Emory Clinic Perimeter. "You really don't need a 'kit' to do this. Cancers of the vulva are relatively rare (usually occurring only in older women). Before performing vulvar/external vaginal exams, you may want to identify with your doctor what is normal. I would, however, not advise women to try their own internal gyncologic examinations. Not only would this be logistcally difficult, but visualizing the cervix is sometimes even difficult for trained health professionals. Unless you know what to look for, i.e., what is normal, then you're not doing yourself any benefit."

MACULAR DEGENERATION

As some people age, the macula in the central portion of the light-catching retina on the back of the eye is prone to changes that may reduce vision. Most persons diagnosed with age-related macular degeneration have the slowly progressive and lesn luteinizing hormone (LH) -- a pituitary hormone which encourages egg cells in the ovaries to produce estrogen. Ovulation usually occurs about a day after the surge is detected.

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