Home-Use Tests
This section provides information about home-use tests to screen
for certain diseases or conditions. For tests prescribed by your
doctor, see the section on lab
tests. You can also use the glossary
from this page.
What Are Home-Use Tests?
Home-use tests allow easy access to medical information about your
health status. They can be cost-effective, quick, and confidential.
Home tests can help:
- detect possible health conditions when you have no symptoms,
so that you can get early treatment and lower your chance of developing
later complications (i.e. cholesterol testing, Hepatitis testing).
- detect specific conditions when there are no signs so that
you can take immediate action (i.e. pregnancy testing).
- monitor conditions to allow frequent changes in treatment (i.e.
glucose testing to monitor blood sugar levels in diabetes).
Despite the benefits of home testing, you should take precautions
when using home-use tests. Home-use tests are intended to help you
with your health care, but they should not replace periodic visits
to your doctor. Many times, you should talk to your doctor even
if you get normal test results. Most tests are best evaluated together
with your medical history, a physical exam, and other testing. Always
see your doctor if you are feeling sick, are worried about a possible
medical condition, or if the test instructions recommend you do
so.
See also: Home Diagnostic
Tests: The Ultimate House Call?
How Can You Get the Best Results With Home-Use
Tests?
Follow the tips listed here to use home-use tests as safely and
effectively as possible.
- Read the label and instructions carefully.
Review all instructions and pictures carefully to make sure you
understand how to perform the test. Be sure you know:
- what the test is for and what it is not for
- how to store the test before you use it
- how to collect and store the sample
- when and how to run the test, including timing instructions
- how to interpret the test
- what might interfere with the test
- the manufacturer's phone number if you have questions
- Only use tests regulated by FDA.
There are several ways to find out if a home-use test is regulated
by FDA. You can ask your pharmacist or the vendor selling the
test. You can also search for the product in FDA's databases (see
"How Can You Know If A Home-Use Test Is Regulated
By FDA.") If a test is not regulated by FDA, the U.S.
government has not determined the product to be reasonably safe
or effective, or substantially equivilant to another legally marketed
device.
- Follow all instructions.
You must follow all test instructions to get an accurate result.
Most home tests require specific timing, materials, and sample
amounts. You should also check the expiration dates and storage
conditions before performing a test to make sure the components
still work correctly.
- Keep good records of your testing.
- Call the "800" telephone number listed on your
home-use test if you have any questions.
- When in doubt, contact your doctor.
All tests can give false results. You should see your doctor if
you believe your test results are wrong.
- Don't change medications or dosages based on a home test
without talking to your doctor.
How Can You Know If an Over-The-Counter
Test Is Regulated By FDA?
To find out if an Over-The-Counter use test is regulated by FDA,
you can look for it in IVD Over-The-Counter Database. To search
the IVD Over-The-Counter Database:
- Enter any word in the name of the test in the first space on
the page where it says “Test Name."
- You might also want to select the “Test Type” from
the drop down menu if you know what kind of test it is.
- You do not need to enter any other information.
- Select Search at the bottom of the screen to submit your request.
The database will search for records that match your request. It
will list the records, and you can select any that interest you.
If the database finds no record of the test you requested, the test
may not be regulated by FDA.
Search
IVD Over-The-Counter Database Now
If the database did not find any record of the test you requested
you may contact us for further information.
Contact Us Now
How Can You Get Consumer Information About
Home-Use Tests?
Home-use tests can be used to screen for different types of diseases
or conditions. Some tests require a doctor's prescription, but most
are available over the counter (OTC) at your local pharmacy. Each
of the links below describe one type of home-use test.
- Cholesterol
[to test your risk of heart disease]
- Drugs of Abuse [to test for illegal drugs]
- Fecal Occult Blood
[to measure blood in stool to screen for colon cancer]
- Glucose [to monitor
blood sugar levels]
- Hepatitis C
[to test for Hepatitis C infection]
- HIV [to test for
HIV infection]
- Menopause [to
determine onset of menopause]
- Ovulation [to determine female fertility]
- Pregnancy [to
determine pregnancy]
- Prothrombin Time
[to measure blood clotting]
- Vaginal pH [to
measure acidity in vaginal secretions]
Should You Buy Home-Use Tests Online?
Although many good home-use tests are available online, others
may not work or may even be harmful. Some tests sold online are
illegal, that is, being sold without FDA's knowledge. If you think
that you have a medical condition or disease, see your doctor or
healthcare professional. Don't try to diagnose yourself with questionable
products obtained over the Internet.
See also: Buying Diagnostic
Tests From the Internet: Buyer Beware!
How Can You Find Out About Problems Reported
To FDA For Medical Tests?
FDA keeps data on medical devices that have malfunctioned or caused
a death or serious injury in the Manufacturer and User Facility
Device Experience (MAUDE) database.
Search
the MAUDE database.
How Can You Report Your Own Problems
With a Test?
If your symptoms don't seem to agree with your test results, or
if your test or device does not seem to be working properly, you
can report it to FDA's MedWatch program.
Report Problems
to MedWatch program.
If you want to notify OIVD directly of a problem with a home-use
test, contact us at fdalabtest@cdrh.fda.gov.
How Does FDA Evaluate Home-Use Tests?
Before home-use tests come to market, FDA receives a submission
from the manufacturer describing the product. FDA reviews these
submissions to determine if:
- the user will get acceptable results from the test compared
to the results obtained when a professional performs the test;
- the user will be able to interpret test results correctly;
and
- the benefits of the test outweigh its risks.
See also: FDA Review of Home-Use Devices
Lab Safety Tips
Home Pregnancy Tests – How to Use a Popular
Test Wisely
(posted 4/2/04)
The first home pregnancy tests were marketed in the mid 1970’s.
These tests are one of the most popular products for home diagnostic
testing. It is estimated that about 33% of women have used these
tests. The tests are popular because they allow women rapid access
to highly sensitive and personal information. These tests can lead
to earlier diagnosis and can provide pregnant women an opportunity
to seek earlier health care intervention.
FDA is involved in the premarket review of these tests. Since the
1976 Medical Device Amendment, FDA assures that new pregnancy tests
perform as well as those tests on the market since 1976. Premarket
compares test performance between a new test and an established
test. In these kinds of pregnancy devices the new test is compared
to varying levels of the hormone human chorionic gonadotropin (hCG)
that is the marker for pregnancy.
Recent investigators point out that the FDA review of analytical
performance does not always mean a woman is pregnant. This discrepancy
is because different tests have different abilities to detect low
levels of hCG. Also hCG levels differ between pregnant women depending
on the timing of the onset of pregnancy with regard to a menstrual
period and depending on each woman’s unique biology.
The result is that pregnancy tests may be labeled up to 99% accurate
when compared to other hCG tests, not to pregnancy. This
may be true based on information submitted to the FDA. Therefore,
labeling of these tests should clearly indicate that there is a
possibility for both false positive tests and false negative tests,
so patients should contact their health care provider to discuss
any result.
Patients may frequently recognize incorrect results with the passage
of time. False negatives may be detected by ongoing failure to have
a period or the development of other obvious signs of pregnancy.
False positives may be demonstrated by the unexpected onset of menses
(regular vaginal bleeding associated with “periods”.)
Repeat testing and/or other investigations such as ultrasound may
provide corrected results.
If a patient has a negative result, it is always wise to consider
this a tentative finding. Women should not use medications and should
consider avoiding potentially harmful behaviors, such as smoking
or drinking alcohol, until they have greater certainty that they
are not pregnant.
Since September of 2003, studies for pregnancy tests have been
posted on the Office of In Vitro Diagnostic Web Page (www.fda.gov/cdrh/oivd/)
under new 510(k)s – decision summaries. FDA is considering
what educational or regulatory tools might be available to help
clarify the status, use, and interpretation of these tests.
Common Problems with the Use of Glucose Meters
Glucose Testing Tips:
Diabetes care has come a long way since the introduction of insulin
and the first oral anti-hyperglycemic medicines. Life span and quality
of life have improved for majority of affected individuals. Even
better, a large part of diabetic care formerly performed in hospital
clinics can now be managed at home with use of well designed home
based glucose meters, a telephone and a good patient-doctor relationship.
The Office of In Vitro Diagnostics (OIVD) is charged with the job
of evaluating many devices, including glucose meters. OIVD helps
these meters come to the public market. Another of its tasks is
the continuous evaluation of the same devices for long term safety
and effectiveness not just of the devices, but of how the devices
are used.
OIVD is taking this opportunity to provide some friendly tips in
Point of Care glucose testing inspired by some comments we have
received from manufactures and users of these devices.
Causes of false results may be patient/sample based or user/device
based. Some common problems and their effects on meter glucose readings
are listed below.
Problem |
Results |
Recommendation |
| Sensor strips not fully inserted into meter |
false low |
always be sure strip is fully inserted in meter |
| Patient sample site(for example the fingertip)
is contaminated with sugar |
false high |
always clean test site before sampling |
| Not enough blood applied to strip |
false low |
repeat test with a new sample |
| Batteries low on power |
error codes |
change batteries and repeat sample collection |
| Test strips/Controls solutions stored at temperature
extremes |
false high/low |
store kit according to directions |
| Patient is dehydrated |
false high |
stat venous sample on main lab analyzer |
| Patient in shock |
false low |
stat venous sample on main lab analyzer |
| Squeezing fingertip too hard because blood is
not flowing |
false low |
repeat test with a new sample from a new stick |
| Sites other than fingertips |
high/low |
results from alternative sites may not match
finger stick results |
| Test strip/“Control” solution vial
cracked |
false high/low |
always inspect package for cracks, leaks, etc. |
| Anemia/decrease hematocrit |
false high |
venous sample on main lab analyzer |
| Polycythemia/increased hematocrit |
false low |
venous sample on main lab analyzer |
The advantage of Point of Care testing is eliminated if proper
technique is not followed. In addition to the above recommendations,
laboratory professionals must remember to wash hands and change
gloves between patients. Also, clean the surface of the meter if
blood gets on it. This each time, every time approach helps
protect both the patient and the health care worker from blood borne
agents like HIV and HCV.
All operators, from patients to non-lab health care workers to
medical technologists and physicians, should be thoroughly familiar
with any device prior to using it. The best way to do this is to
read the package insert and user manual carefully before
using a device for the first time. It sounds simple, and it is.
If you have any questions, ask someone who is familiar with the
device. Another option is calling the customer service telephone
number located on most package inserts. The people on the other
end are there to help. Another good tip is to reread the package
insert every few months. It is a good practice and their may be
changes.
Next, watch an experienced laboratory professional, doctor, nurse
or diabetic educator perform the test. Then perform the test in
front of someone who has experience in using the glucose meter and
instructing others on its performance. Ask for tips.
Specific problems come up from time to time including glucose readings
that don’t make sense. For example you might feel fine when
the glucose meter reading is obviously too high or too low. Remember,
the best way to resolve any questionable result, and the best sample
from any sick patient, is still a venous blood sample tested at
a central lab. Even then any result that does not fit the clinical
picture needs to be investigated and, at a minimum, repeated.
For more information also see FDA’s diabetes website at:
http://www.fda.gov/diabetes/
Updated 5/1/03
Glucose Meter Test Results: Useful Tips to
Increase Accuracy and Reduce Errors
Have you ever wondered why you got a bad glucose meter test result
when there is nothing obvious wrong with your meter, your test strips
are new, and you’ve been running glucose tests for years?
The simple answer is that glucose meters are not perfect, and neither
are the people who use them! This chart lists some tips to help
you get the most accurate results from your glucose meter.
| Make
sure you... |
Because |
- follow the user instructions about sample size. Repeat
the test if you have any doubt that enough blood was added.
|
If there is insufficient blood on the test strip,
the meter may not be able to read the glucose level accurately.
Although many meters are designed to alert you when the sample
size is too small, some meters detect only large errors. There
have been cases where meters have displayed glucose levels that
were less than half the actual levels without displaying error
messages. |
- insert the test strip completely into the meter guides.
|
When a test strip is not fully inserted into
the meter, the meter cannot read the entire strip area. Many
meters are designed to detect strip placement errors and will
not provide a result. But, just as described above, many meters
detect only large problems. There have been cases where meters
have displayed glucose levels that were significantly higher
or lower than the actual levels when there was only a small
error in strip placement. |
|
Even small amounts of blood, grease, or dirt
on a meter’s lens can alter the reading. |
- check the test strip package to make sure the strips are
compatible with your meter.
|
Test strips are not always interchangeable, and
meters cannot always detect incompatible strips. Test strips
that look alike may have different chemical coatings. Small
variations in strip dimensions can also affect results. |
- check the expiration date on the test strips.
|
As a test strip ages, its chemical coating breaks
down. If the strip is used after this time, it may give inaccurate
results. |
- enter the correct calibration code from the outside of
the strip bottle each time you run a test (if applicable).
|
Results can vary significantly between manufactured
lots of reagent strips; the calibration codes help the meter
compensate for these variations. |
- run quality control as directed.
|
Running quality control is typically the only
way to know when test strips have gone bad. Test strips do not
always last until the expiration date on the bottle. This may
be because the manufacturer has over-estimated the dating or
because the cap was not replaced promptly after use. |
- check the results from your meter against laboratory results
as often as possible.
|
Over time, test systems can drift apart. Since
results from either test system maybe used to treat your patients,
it is important for the systems to remain synchronized. |
- question results that are not consistent with physical
symptoms. If a test result seems wrong, have a blood sample
tested by the main laboratory.
|
There may be many reasons why a test result is
incorrect. In addition to the items above, some physiological
conditions such as dehydration, hyperosmolarity, high hematocrit,
or shock may significantly affect test results. |
|
