Should you get blood work done when sick? Answers on risks and using tests

Should You Get Blood Work Done While Sick?

Getting sick is never fun. Between the symptoms that make you miserable and having to take time off from work or school, being under the weather can really put a damper on life. When you're not feeling well, your first instinct may be to make an appointment with your doctor to find out what's wrong and how to start feeling better. During this appointment, your doctor may recommend getting some blood work done to help diagnose your illness. But is getting blood drawn and tested really necessary when you're already sick? Here's what you need to know about getting blood work done while you're sick.

Why Doctors Recommend Blood Work When Sick

There are a few key reasons why your doctor may want you to get blood testing done when you're sick:

• To help diagnose the illness. By looking at certain markers in your blood, your doctor can get clues about what is going on in your body. Blood work can help confirm or rule out certain conditions.
• To check for complications. Some illnesses can cause complications that may not have obvious symptoms at first. Blood tests can help spot early warning signs of complications.
• To monitor severe illnesses. For severe infections or illnesses, blood testing allows doctors to keep an eye on how your body is responding to treatment.
• To screen for other conditions. Blood work results can sometimes reveal other underlying conditions you may not have known about.

So in short, blood testing when you're sick provides important diagnostic information to help guide treatment. Without it, your doctor may be left guessing more about what is wrong.

Common Blood Tests Doctors Use

If your doctor orders blood work when you're sick, what exactly will they be testing? Some of the most common blood tests used to diagnose and monitor illnesses include:

• Complete blood count (CBC) - Measures levels of different cells in your blood, including red blood cells, white blood cells, and platelets.
• Basic metabolic panel - Checks electrolyte, kidney, and glucose levels.
• Inflammatory markers - Tests for signs of inflammation and infection, such as sedimentation rate or C-reactive protein.
• Liver function tests - Assess how your liver is working by measuring enzymes and proteins.
• Thyroid panel - Screens thyroid hormone levels to uncover thyroid problems.
• Infectious disease testing - Specific tests that can identify antibodies or antigens from certain infections, like mononucleosis.

There are many more blood tests that provide doctors with clues about what's happening inside your body when you're sick. The testing your doctor chooses will depend on your symptoms and their initial suspicions about your illness.

Is Blood Testing Accurate When You're Sick?

A common concern is whether blood testing is affected by being ill. Are the results still accurate and reliable? In most cases, getting blood drawn and tested while you're sick should not significantly impact the accuracy of the results.

For routine blood tests like a CBC or metabolic panel, there is no evidence sickness substantially alters results. Your white blood cell count may be elevated because your immune system is ramped up, but for most basic blood tests, the results should still provide useful diagnostic information.

One exception is that certain illnesses, like severe infections or cancers, can temporarily impact certain organ functions. So tests related to the kidney, liver or thyroid function may be harder to interpret in the context of a serious illness. But overall, blood testing remains a useful diagnostic tool even when you're under the weather.

Tips for Getting Your Blood Drawn When Sick

If your doctor has ordered blood work to help figure out your sickness, here are some tips to make the process smoother:

• Ask if you can get blood drawn at your doctor's office. This avoids an extra trip to a third-party lab.
• Tell the phlebotomist you're sick. They may be able to take extra precautions.
• Bring water and snacks to drink and eat afterwards to avoid feeling lightheaded.
• Apply a cool compress to the blood draw site afterwards if you tend to bruise easily.
• Get plenty of rest after. Blood draws can make you feel more tired.
• Call with any questions about preparing for the blood test. Fasting or medication changes may be required.

Potential Risks of Blood Testing When Sick

While in most cases getting blood drawn and tested while you're ill is safe and worthwhile, there are a few potential downsides to consider:

• It may require extra trips out when you feel miserable. However, many doctors can draw blood in-office.
• You may have more difficulty getting to the lab if you're very ill.
• Drawing blood could theoretically increase your infection exposure risk.
• Testing too early in an illness may not reveal anything useful yet.
• The blood draw may worsen certain symptoms like fatigue or dizziness temporarily.

Discuss any major concerns about getting blood work done with your doctor. But in most cases, the benefits will outweigh these risks.

What Blood Testing Cannot Tell Your Doctor

While blood work is a useful diagnostic tool when sick, it's important to understand it has some limitations. Blood testing cannot:

• Definitively diagnose all conditions. It provides clues but further testing is often needed.
• Reveal the cause or source of an infection.
• Show where inflammation or damage may be occurring in the body.
• Replace a full physical exam.
• Distinguish between different types of infections or illnesses that have similar markers.

Blood work when sick should be seen as one piece of the puzzle. Your doctor will combine it with your symptoms, exam findings, medical history and other test results to reach a diagnosis.

When to Get Blood Work Done if You're Sick

Deciding when to get blood testing done when you're under the weather depends on several factors:

• Severity of symptoms - The worse you feel, the more likely blood work could be helpful for your doctor.
• Duration of illness - Blood testing is more useful if you've been sick for several days to weeks vs just a day.
• Type of symptoms - Certain symptoms like fever, fatigue and sudden weight loss warrant testing.
• Presence of risk factors - Underlying conditions or older age make testing more advisable.
• Doctor recommendation - Your doctor may specifically advise blood work based on initial evaluation.

As a general guideline, consider asking your doctor about getting blood work done if:

• Your illness or symptoms have persisted over a week with no improvement.
• You have a fever over 101 F that won't resolve.
• You're experiencing significant fatigue, appetite changes or unexpected weight loss.
• You have severe pain, swelling or confusion.
• You are at higher risk due to old age, pregnancy or chronic conditions.
• Over-the-counter medicines are not helping your symptoms.

Listening to your body is important. Make an appointment to get evaluated sooner rather than later if your symptoms concern you.

Questions to Ask Your Doctor About Blood Testing

Having blood work done while sick can provide valuable insights about what's going on with your health. But it's important to discuss the purpose and implications of testing with your doctor too. Here are some suggested questions:

• Why do you think I need blood testing at this time?
• What types of blood tests will be done? What will they show?
• When will the results be available? How will you communicate them to me?
• Could any medications or other factors impact my results?

FAQs

Can blood tests still be accurate if I'm sick?

Yes, most routine blood tests like a complete blood count or metabolic panel will still provide accurate results even if you are sick. Illness can elevate certain markers like white blood cells, but overall the tests are still useful for diagnosis.

What are the risks of getting blood drawn when sick?

Potential risks include increased fatigue after the blood draw, lightheadedness if you are already dehydrated, and a small chance of increased infection exposure by visiting a lab. Discuss any concerns with your doctor.

Can blood tests diagnose any illness?

No, blood tests can only provide clues and must be combined with a full history and exam. They cannot definitively diagnose most conditions on their own or pinpoint the cause of an infection.

Should I get blood work done for mild symptoms?

Blood work is not usually recommended for mild short-lived symptoms. But if you have symptoms persisting over a week without improvement, it's reasonable to ask your doctor about getting tested.

What questions should I ask my doctor about testing?

Ask why testing is recommended, what specific blood tests will be done, when results will be ready, if medication or other factors could impact results, and what further testing may be needed.