How to prepare for diagnostic tests

How to prepare for diagnostic tests

January 21, 2023
7 min read

A laboratory (lab) test is a procedure used by a health care provider to get information about your health by collecting a sample of your blood, urine, other bodily fluids, or body tissue. Laboratory tests are routinely used to assist in the diagnosis or screening of an illness or condition. Screening aids in the early detection of illnesses. Other tests are performed to monitor an illness or to determine whether or not a medication is beneficial. In addition, lab tests may be performed to offer more broad information on your organs and bodily systems.

For example, a student who is having difficulties reading may be subjected to diagnostic testing to discover whether he or she has dyslexia or visual impairment.

If you want to take one of these tests, here is some very general information that you should know about before appearing for the test.

General guidelines to get prepared for lab tests-

  • You should compulsorily follow all the instructions given by your health provider.
  • Be honest. It is very necessary to tell the professional if you didn’t follow the exact instructions given by them. As even minor changes can have hazardous effects on your health. Example- Some medications may increase or decrease blood sugar levels. Taking them too close to a blood sugar test might affect your results.
  • Inform the lab professional about the drugs and supplements you have been using prior. Following these guidelines will almost certainly result in the most dependable and accurate outcomes.

Other frequent test preparations include:

  • Avoiding certain meals and beverages, such as cooked meats, herbal tea, and alcohol
  •  Avoiding overeating the day before a test
  • Avoiding certain activities, such as rigorous exercise and sexual activities
  • Smoking cessation
  • Avoid certain medications and/or supplements. Discuss any medications you are currently taking with your doctor, including over-the-counter medications, vitamins, and supplements.
  • You may be urged to drink additional water before some blood tests to assist retain more fluid in your veins. Drinking water 15 to 20 minutes before some pee tests may also be required.

After taking all these measures, if you still are concerned and have more questions about certain tests, talk to your healthcare provider and ask him for the additional measures as it varies from test to test.


Blood tests prerequisites

There are some specific tests that need extra/ special preparations.

Some of the most common lab tests include fasting and those are-

Some of the most popular lab tests that need additional specific preparations are:

  • Creatinine Test, which may require fasting or avoiding cooked meats
  • Cortisol Test. For this test, you may need to rest for a bit before your sample is taken. You may also have to avoid eating, drinking, or brushing your teeth for a certain time before your test.
  • Fecal Occult Blood Test. For this test, you may need to avoid certain foods or medicines.
  • 5-HIAA Test. For this test, you may be asked to avoid a variety of specific foods. These include avocados, bananas, pineapples, walnuts, and eggplants.
  • Pap Smear. A woman may be instructed not to douche, use tampons, or have sex for 24 to 48 hours before this test.


Fasting for a Blood Test

Sometimes, people are advised to fast before tests.

Creatinine test, which may need fasting or abstaining from cooked meats Foods and drinks are absorbed into your system when you eat and drink properly and this might have an impact on the outcomes of some blood tests.

What kinds of blood tests require the patient to fast?

Glucose Tests- Blood sugar levels are determined via glucose testing. A glucose tolerance test is one kind of glucose test. You must fast for eight hours prior take this exam.

You will get your blood tested when you get to the lab or medical institution. Drink a glucose-containing specialty beverage. Test your blood again after one hour, two hours, and potentially three hours.

Diabetes is diagnosed with glucose testing.


Lipid tests- These tests detect cholesterol, a waxy molecule that resembles fat and is present in all of your body's cells as well as triglycerides, a form of fat found in the circulation. You may be at risk for heart disease if you have high levels of triglycerides and/or LDL cholesterol.

Some people also ask if it is okay to have any other fluid except water during the fast, but the answer is no. Coffee, soda, juice, and other drinks can enter your bloodstream and influence your outcomes. Additionally, you must not:

  1. Chew gum
  2. Smoke
  3. Exercise

Your outcomes may also be impacted by these activities.

However, you can have water. Drinking water before a blood test is advised. It assists in maintaining more fluid in your veins, making it easier to draw blood.

What are the general guidelines to get prepared for lab tests?
What are the specific tests that require fasting?
How long should I fast before a blood test?
Can I keep taking my medication when I'm fasting ?
When can I resume eating and drinking normally?
Can I drink coffee before a lab test?
How should I collect a urine sample for a lab test?
Can I exercise before a lab test?