U.S. Pharmacist

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The Value of Nonprescription Home Test Kits

W. Steven Pray, PhD, DPh
Bernhardt Professor, Nonprescription Products and Devices
College of Pharmacy, Southwestern Oklahoma State University

Weatherford, Oklahoma



4/19/2010

US Pharm
. 2010;35(4)(OTC suppl):3-8. 

The history of self-care diagnostic test kits is short but dynamic. Until the 1970s, the only home kits were diabetic urine tests. Testing at home for such conditions as pregnancy was unheard of. If a woman wished to determine whether she was pregnant, she made a physician appointment, provided a urine sample, and waited several days before learning the outcome. The situation began a radical upheaval in 1977 with the introduction of a new OTC product that revolutionized the self-care arena—the original e.p.t Pregnancy Test (e.p.t stands for early pregnancy test).1 Three decades later, few remember or understand the professional and public controversy that surrounded e.p.t’s introduction. For instance, some feared that teens might increase sexual activity since they would be able to discover (and perhaps terminate) pregnancy without informing their parents. Physicians and pharmacists feared that the product’s accuracy might be questionable. However, the public embraced the product to the extent that competitors soon appeared and home pregnancy tests underwent numerous design changes. Further, home pregnancy tests were just the beginning of a host of additional home diagnostic kits for dozens of uses.2 Some have been controversial, such as home HIV/AIDS tests, but the overall concept of home testing kits has gained widespread acceptance. 

General Advice for Home Test Kits

Home test kits allow patients to be personally involved in diagnosing or monitoring their health. However, pharmacists must provide general advice for all kits.2 Patients must be urged to read all directions provided by the manufacturer and to follow them exactly. If the test requires waiting a specific time before reading it, patients must not estimate when the appropriate amount of time has passed but should use a watch or clock with a second hand. Should they fail to do so, the developing color or indicator may not register correctly. Patients should also be advised to check the expiration date prior to use if the kit is not to be used immediately. 

Home Pregnancy Tests

Many women wish to learn whether they are pregnant, as discovering pregnancy early allows the woman to decide whether to carry the pregnancy to term (early termination of pregnancy decreases the risk of complications), gives her a warning to stop taking any drugs that might have adverse effects on her fetus (e.g., alcohol, caffeine, marijuana, methamphetamine, cocaine), and alerts her to consult with her physician about safer alternatives for regularly ingested medications (e.g., stopping Accutane for acne).2 She can also halt any x-rays of the abdomen. Her physician can calculate her due date more accurately, cease scheduled fertility treatments, and initiate prenatal vitamins and minerals. 

Home pregnancy tests are simple to use. The patient removes the test stick from the wrapper and takes off the cap. She holds the stick in her urine stream for 5 to 10 seconds and reads it when directed, discarding it after use.3 

Pregnancy tests measure human chorionic gonadotropin (hCG) produced by the trophoblast of the fertilized ovum.2,3 Levels of hCG rise to detectable status a few days before the end of the first month of pregnancy and are most reliably detected after the first missed period. A problem arises because tests have vied for years to advertise themselves as the earliest to detect pregnancy, either through package wording or the very trade names themselves (e.g., First Response). A number of years ago, the manufacturers began to claim accuracy in testing before the period is missed. The earlier the patient uses such tests, however, the lower her hCG levels and the less likely that pregnancy will be detected. Thus, testing too early will result in many false negatives. The accuracy of the tests is claimed to be 99%, but independent testing has challenged those figures.3,4 The manufacturer of one test provides a chart warning the patient about testing too early.5 If patients test one day before their missed period, only 87% will get a positive result. Testing 2, 3, or 4 days before the missed period gives positive results in only 84%, 74%, and 53% of cases, respectively. Thus, testing 4 days before the missed period as advised by the majority of currently available tests may miss pregnancy at least 47% of the time. As a result of this uncertainty, the patient should be advised that if her test is negative and her period still has not started 3 days later, she should test again. If the test remains negative, she should make an appointment to see a physician to discover if she has a medical condition that requires intervention. 

Accu-Clear is a home pregnancy test that suggests testing the first day of the missed period, making it possibly more reliable than other tests.6 Many of those other tests state “test 5 days sooner,” with the numeral “5” prominently displayed. Their labels imply that the patient can test 5 days before the day the period is expected to start. However, on closer reading, the package actually directs the user to test 5 days sooner than waiting until the period is missed (e.g., the day after the period was expected to begin). Thus, the patient in actuality is to test 4 days before the missed period rather than 5 as implied by the package. Such products also include Answer Early Result, Clearblue Easy Digital, e.p.t Digital, First Response, First Response Gold Digital, and Fact Plus (TABLE 1).7 

If the patient is testing early, she should use first morning urine to maximize the chances of picking up the smaller levels of hCG.5 If she is testing later (e.g., after the period is expected to begin), she may test urine at any time. Patients are warned that drinking large amounts of fluid before testing may cause false negatives. False positives with home pregnancy tests can also result if the patient has had a miscarriage or birth within the past 8 weeks or if she is using fertility medications that contain hCG (e.g., Profasi, Pregnyl).2,5

Ovulation Prediction Tests

Pregnancy is an elusive goal for perhaps one in six couples due to fertility problems. The woman may be ovulating irregularly or the man’s sperm count may have dropped.2,8,9 Male issues cause infertility 33% of the time. Ovulatory disorders and other female issues are responsible for 33% of cases, and the rest are undetermined or due to both partners.9 Either may have residual damage from a prior sexually transmitted disease. Several products can help couples achieve pregnancy.8 Female issues may be detected with several approaches, such as fertility monitors, ovulation prediction kits, basal body temperature monitoring, or salivary ovulation tests. 

Fertility Monitor: Clearblue Easy Fertility Monitor is a $150 handheld electronic system that measures luteinizing hormone (LH) and estrogen.2,10 Twenty test sticks come with the initial purchase, and the patient may buy additional test sticks. The company claims 99% accuracy in detecting the LH surge. To use this product, a woman first presses an “m” button on the monitor the morning after her period begins, which sets the monitor at day 1.10 Setting the “m” button at a certain time of the day (e.g., 10 am) indicates that the woman will be able to test during a window that runs from 3 hours prior to that time (e.g., 7 am) to 3 hours after that time (e.g., 1 pm). This monitor requests testing only on specific days; the woman should not test on days that the monitor does not request it. The woman turns the monitor on each day during the testing window, prior to urinating. After the stick is exposed to urine, the monitor notifies the patient of low, high, or peak fertility status. Couples can maximize the chance of pregnancy by engaging in sexual activity on at least one day of high fertility and one day of peak fertility.2,8 

The major advantage of the fertility monitor over the older ovulation prediction kits is that detecting the rise in estrogen informs the user of an additional 1 to 5 days of high fertility prior to her peak fertility days. This “fertility window” maximizes chances of a successful conception. Products that identify the window of fertility are increasingly being recognized as superior to other methods. Older products only identify 2 days of peak fertility.  

Results can be affected by tetracycline and by medications that affect the menstrual cycle, including hormonal contraceptives, fertility products containing LH or hCG, and hormone replacement therapy.10 Prescription clomiphene (Clomid) may affect the monitor’s ability to detect high-fertility days. A fertility monitor is most appropriate for women whose cycles last from 21 to 42 days, but women who have had a recent pregnancy, stopped breast-feeding, halted hormonal contraceptives, or had other treatments that affect the cycle should wait to use it until they have had two consecutive normal menstrual cycles. 

Ovulation Prediction Kits: Ovulation prediction kits include Clearblue Easy Digital, Accu-Clear Early Ovulation Predictor, Answer Daily Ovulation Tracker, Answer One-Step Ovulation Test, EarlyDetect Ovulation, and  First Response Ovulation Test (TABLE 1).2,7 Ovulation prediction kits do not indicate days of high fertility and thus may lead to lower rates of conception. Nevertheless, they remain popular because they are relatively simple to use and are less expensive than fertility monitors. Ovulation prediction kits measure LH in the urine, which typically surges from 24 to 36 hours prior to ovulation.2,8 Before using an ovulation prediction kit, a woman should have an approximate idea of when she ovulates. Because most menstrual cycles range from 21 to 40 days, a woman may ovulate from day 5 to day 23 of the cycle. She begins testing her urine using the five to seven sticks when suggested by an enclosed chart (generally 2-4 days before ovulation is expected); she may need to purchase a second kit if the first does not detect the LH surge. Patients may test at any time of the day but should test at the same time each day. Fluids should be reduced for 2 hours prior to testing to help ensure that LH is detected. 

Women who ovulate irregularly may not be able to detect the LH surge. Menopause and polycystic ovary syndrome elevate LH levels and can cause false positives. Having undergone an abortion less than one month prior to testing also makes the results unreliable. The patient should allow two normal cycles before trusting the results. Tetracycline, hormonal contraceptives, fertility treatments containing LH or hCG, and hormone replacement may affect the results. Clomid can increase LH levels; women should wait 3 days after stopping it before using these tests.8 If the patient has used these products for 3 months and failed to detect a surge, she should make an appointment with her physician. 

Basal Body Temperature Monitoring: Women may also use basal body temperature thermometers to monitor fertility. These digital thermometers (e.g., BD Digital Basal Thermometer) depend on the physiological fact that a woman’s temperature rises slightly after ovulation.2 The woman takes her temperature under basal (standardized) conditions, such as prior to arising from bed, eating, drinking, or smoking. An enclosed chart helps her track temperature variations. When the temperature is rising, peaking, and falling, intercourse is more likely to result in conception. Once used as contraceptive devices, basal thermometers are now promoted solely to increase the likelihood of conception. 

Salivary Electrolyte Examination: A well-known fertility-awareness technique is to test cervical mucus with the fingers to detect periovulatory changes. Several devices (e.g., MaybeMOM, Fertility Scope) claim to help patients monitor fertility using similar methodology. Females undergo an electrolyte change approximately 3 to 4 days prior to ovulation that persists for 2 to 3 days following ovulation. When a saliva sample is dried, it exhibits specific microscopic fernlike characteristics.11 These devices include a microscope and laboratory slides. The patient tests at the same time each morning, just upon arising, before consuming any food or water, and prior to smoking. She licks one slide and allows it to dry for 5 to 10 minutes. Upon microscopic examination, a clear slide is said to indicate infertility, and fernlike crystals indicate the time surrounding ovulation. The FDA cautions that these tests suffer from numerous shortcomings. For instance, not all women “fern,” others may not be able to see the ferning, women who fern on some days of the period do not necessarily fern on all fertile days, and ferning can be disrupted by smoking, eating, drinking, brushing the teeth, how the saliva is placed on the slide, and where the woman was when she conducted the test.9 

Male Fertility Test: A product known as Baby Start Male Infertility Test measures the male sperm count to detect male issues causing infertility.12 The minimal standard for full male fertility is 20 million sperm per mL of ejaculate. Baby Start has two sperm count tests. The male ejaculates, waits 15 minutes, and places the ejaculate in a test cassette, reading the results when indicated. 

Blood Glucose Monitors

Throughout much of the 1970s, patients with diabetes who sought to determine the percentage of glucose in the blood were only able to do so through using sticks, strips, or tablets to test urine (e.g., Clinistix, Clinitest, Diastix, Tes-Tape).2 The advent and widespread acceptance of blood glucose monitors (meters) in the mid-1970s revolutionized control for patients with diabetes. Since their inception, blood glucose monitors have undergone numerous changes, each designed to make them more user-friendly and increase their utility. 

The Rapidly Changing Market: Blood glucose monitors appear on the surface to be small, uncomplicated devices. However, they are in actuality extremely intricate machines that use the latest technological advances to provide an accurate reflection of blood glucose. As soon as one manufacturer develops an innovative and useful new feature for its monitors, other companies must determine whether it is worth emulating to improve the health of that company’s purchasers. As a result of this rapidly changing market, blood glucose monitors experience an obsolescence virtually unprecedented among devices sold in pharmacies. 

The cost of blood glucose testing strips is a major issue behind the dynamic nature of the blood glucose testing market. Each monitor requires a specific strip, a requirement so exact that when a meter is discontinued, the strips often become impossible to locate, forcing patients to purchase a new meter. A box of 50 blood glucose test strips may sell for $30 to $40, and a box of 100 strips may retail for $60 to $75.13 

The Importance of Counseling: Blood glucose monitors are complicated, but pharmacists can provide general advice. The patient should follow a standard set of steps, such as first washing the hands with soap and warm water.14 The sample area or site should be cleaned with alcohol and allowed to dry thoroughly. The lancet should be used to puncture the skin at the site indicated. The patient must follow directions for inserting the strip and using the meter. The patient should read the instructions for both prior to first use. Keeping the manuals will allow patients to troubleshoot the meter should an error message appear. 

Calibration Issues: Most glucose meters require pre-use calibration.14 This may consist of entering a calibration code or use of a check strip. Some autocoding meters utilize special test strips that eliminate the need for coding, as calibration occurs with each strip insertion. Meters can usually read blood glucose values ranging from 0 to 600 mg/dL. However, patients are urged by the FDA to interpret very high or low values with extreme caution.15  

Sample Size Required: One of the disincentives to testing blood glucose is the need to obtain blood samples. Older blood glucose meters required 4 to 10 mcL of blood, a volume that dictated using the finger’s rich blood supply as a site.14,15 Unfortunately, the fingers also have the nerves required for sensitivity of touch. Thus, repeated blood withdrawal produces a pain/discomfort that endures throughout the day and causes patients to skip tests. To help prevent this discomfort-associated noncompliance, manufacturers gradually decreased the sample size required by the meters (sample sizes decreased to 1 mcL, then to 0.6 mcL, next to 0.3 mcL). This innovation opened the possibility of sampling at alternative sites. Withdrawal at alternate sites reduces pain because the needlestick can be more shallow, and there are relatively fewer nerve endings in the palm, forearm, upper arm, calf, or thigh. 

The FDA has issued precautions related to alternate-site testing.14,15 The FDA asserts that blood in the fingertips exhibits changes in blood glucose more rapidly than blood in other sites. This could be crucial, as the alternate sites may not reflect the current blood glucose when blood glucose is undergoing rapid change (e.g., following a meal, insulin administration, or exercise). The FDA also warns patients not to test at an alternate site if they think they are hypoglycemic, if they are not aware of symptoms when they experience hypoglycemia, or if alternate site results do not agree with patients’ perception of their blood glucose.  

Other Features: Test solutions are often supplied with the initial meter purchase and are also available separately from pharmacies. Patients must understand that these quality control checks help ensure accuracy of testing. Patients may drop meters, immerse them in water, or expose them to heat (e.g., the inside of a car in summer) or extreme humidity, causing inaccurate readings. Test solutions are used as though they were the blood sample. The results provided by the meter are compared to the value the control solution should provide. If they differ, the monitor is not working properly. Manufacturers may also include a cartridge or special control test strip with the meter to indicate that the meter is performing according to specifications. Most blood glucose monitors store previous readings, including the time and date of the reading. The number of previous readings varies with the specific meter. Many meters include download capabilities, allowing users to transfer readings directly to their home computer, obtaining 14- and 30-day averages as well as averages of all readings taken at any specific time (e.g., 6 am or noon). 

Other Home Test Kits

Home pregnancy tests, ovulation predictors, and blood glucose monitors constitute the majority of the home test kit market. However, there are numerous other tests that patients might request (TABLE 1), some of which should be discussed briefly. 

Colorectal Cancer: While at least two tests are available for home testing for occult blood in the stool that might indicate colorectal cancer, their value is debatable. The U.S. Preventive Services Task Force issues recommendations for screening, including such examinations as colonoscopy, flexible sigmoidoscopy, CT colonography, and physician-supplied high-sensitivity fecal occult blood tests (e.g., Hemoccult II) that are read by a physician and laboratory.16,17 Federal agencies accord no role to home tests that are purchased in pharmacies and read by the patient (e.g., ColoCARE, EZ Detect). 

Urinary Tract Infections: AZO Test Strips claim to allow a patient to diagnose a urinary tract infection (UTI) by detecting white blood cells and nitrite.18 The manufacturer suggests that the patient use the strips at the first sign of a UTI, such as pain, burning, urgency, or frequency. Whether or not the patient obtains a positive or a negative result with residual discomfort, the pharmacist should always suggest a physician appointment, rather than purchase of nonprescription phenazopyridine tablets, which only relieve symptoms and do not treat the infection. 

Menopause: The RU25 Plus Menopause Test Kit measures follicle-stimulating hormone to detect the increase that occurs with onset of perimenopause and menopause.19 It allows the woman with recently missed menstrual periods, vaginal dryness, irritability, night sweats, insomnia, and hot flashes to decide whether they are due to menopause or to another cause. 

Blood Alcohol: QED A150 is a saliva test that detects salivary alcohol in a range of 0.0% to 0.145%.20 The company claims good correlation with blood alcohol. However, it is questionable to advise a drinker who wishes to drive to rely on the results of this test. 

Drug Screening: First Check is a family of drug tests that allow urine to be tested for various combinations of marijuana, cocaine, methamphetamine, opiates (heroin), ecstasy, amphetamines, barbiturates, tricyclic antidepressants, benzodiazepines, methadone, PCP, and oxycodone. The company claims 99% accuracy, comparable to a laboratory screening.21 

Cholesterol: CholesTrak is a fingerstick test for total cholesterol that requires the user to place 1 to 2 drops of blood into a device.22 It does not provide HDL or LDL levels. 

HIV/AIDS: The Home Access HIV-I Test System and Home Access Express are examples of kits that require the user to send a blood sample to a laboratory, phoning them at a specified period of time to obtain results.23 The FDA characterizes the tests as very reliable. No other tests are FDA approved for home HIV detection. 

Paternity: A company known as GeneSys Biotech allows patients to test for paternity.24 The patient takes buccal swabs of the left and right cheek for himself and the child of concern. Using devices supplied by the company, the patient inserts both samples in an envelope supplied with the kit and mails them in. The company uses the polymerase chain reaction to test DNA, providing either a 100% exclusion as the child’s father or a 99.99% inclusion as the father. 

Other Tests: Patients can also test for vaginal fungal infections (e.g., Vagisil Screening Kit), prostate specific antigen, and dozens of other problems and laboratory values. Several companies offer the tests discussed here and many others.25 The pharmacist can point out these vendors to interested patients. 

Conclusion

Home tests kits are a volatile and ever-changing market. Manufacturers constantly introduce new products and modify existing products to incorporate technological advances. It is critical for the pharmacist to stay abreast of this market to allow patients to maximize the benefits of self-testing. 

REFERENCES

1. A timeline of pregnancy testing. National Institutes of Health. http://history.nih.gov/ exhibits/thinblueline/ timeline.html. Accessed March 1, 2010.
2. Pray WS. Nonprescription Product Therapeutics. 2nd ed. Baltimore, MD: Lippincott Williams & Wilkins; 2006.
3. Pregnancy tests. The National Women’s Health Information Center. www.womenshealth.gov/faq/
pregnancy-tests.cfm. Accessed March 1, 2010.
4. Home pregnancy tests: how to use a popular test wisely. FDA. www.fda.gov/MedicalDevices/
Safety/AlertsandNotices/ TipsandArticlesonDeviceSafety/ ucm109396.htm. Accessed March 1, 2010.
5. Fact Plus: the Fact Plus Pregnancy Test Stick. Swiss Precision Diagnostics. www.factplus.com/product_
details.php. Accessed March 1, 2010.
6. Cole LA, Sutton-Riley JM, Khanlian SA, et al. Sensitivity of over-the-counter pregnancy tests: comparison of utility and marketing messages. J Am Pharm Assoc. 2005;45:608-615. www.medscape.com/viewarticle/
515242. Accessed March 1, 2010.
7. Various products. www.drugstore.com. Accessed March 1, 2010.
8. LH urine test (home test). MedlinePlus. National Institutes of Health. www.nlm.nih.gov/medlineplus/
ency/article/007062.htm. Accessed March 1, 2010.
9. Infertility. MedlinePlus. National Institutes of Health.  
www.nlm.nih.gov/medlineplus/
infertility.html. Accessed March 1, 2010.
10. Frequently asked questions about the Clearblue Easy Fertility Monitor. www.clearblueeasy.com/
clearblue-easy-fertility- monitor-faq.php. Accessed March 1, 2010.
11. Ovulation (saliva test). www.fda.gov/MedicalDevices/
ProductsandMedicalProcedures/ InVitroDiagnostics/ HomeUseTests/ucm126061.htm. Accessed March 1, 2010.
12. Baby Start (FertilMARQ). Test Medical Symptoms @ Home, Inc. www.testsymptomsathome.com/
emb01.asp. Accessed March 1, 2010.
13. Pray WS. Self-monitoring of blood glucose: more effective with patient monitoring. Power-Pak C.E. www.powerpak.com/index.asp?
page=courses/105843/ disclaimer.htm&lsn_id=105843. Accessed March 2, 2010.
14. Glucose testing devices. www.fda.gov/MedicalDevices/
ProductsandMedicalProcedures/ InVitroDiagnostics/ GlucoseTestingDevices/default. htm. Accessed March 1, 2010.
15. Getting up to date on glucose meters. www.fda.gov/ForConsumers/
ConsumerUpdates/ucm049051.htm. Accessed March 1, 2010.
16. Screening for colorectal cancer. Recommendation statement. U.S. Preventive Services Task Force. October 2008. www.ahrq.gov/clinic/uspstf08/
colocancer/colors.htm. Accessed March 1, 2010.
17. Colorectal cancer screening tests. Centers for Disease Control and Prevention. www.cdc.gov/cancer/colorectal/
basic_info/screening/tests.htm . Accessed March 1, 2010.
18. AZO Test Strips. Amerifit Brands, Inc. www.azoproducts.com/products/
azo_test_strips_directions. Accessed March 1, 2010.
19. A breakthrough in menopause testing. www.home-menopause-test.com. Accessed March 1, 2010.
20. QED saliva alcohol test kits. Blue Grass Drug Screen, Inc. www.usscreeningsource.com/qed_
alcohol_test_kits.htm. Accessed March 1, 2010.
21. First Check products. First Check Diagnostics Corp. http://secure.
firstcheckfamily.com/First- Check-products-C1.aspx. Accessed March 1, 2010.
22. CholesTrak Total Cholesterol Test. AccuTech, LLC. www.accutech-llc.com/
cholestrak.html. Accessed March 1, 2010.
23. Testing yourself for HIV-1 questions and answers. FDA. www.fda.gov/
BiologicsBloodVaccines/ SafetyAvailability/ HIVHomeTestKits/ucm126460.htm. Accessed March 1, 2010.
24. Home DNA test kit procedures. GeneSys Biotech. www.paternity-answers.com/
home-test-procedures.html. Accessed March 1, 2010.
25. Home health testing. www.homehealthtesting.com. Accessed March 1, 2010.
26. Diabetes Technology. Meters and monitors. Diabetes Network. www.diabetesnet.com/diabetes_
technology/blood_glucose_ meters.php. Accessed March 1, 2010.
27. Vagisil screening kit. Combe, Inc. www.vagisil.com/kit/. Accessed March 1, 2010. 

To comment on this article, contact rdavidson@uspharmacist.com.

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