Sometimes, you may be called by the doctor’s office or laboratory to come back and do a blood test. When that happens, there is nothing to worry about. There are so many reasons why the laboratory or the doctor’s office may call you to redo a test.
Some of the reasons can include an error on the doctor’s, patient’s, or technician’s part, an accident during transport and handling, or even lab errors inside the laboratory.
The reason is not necessarily that something is wrong with you. Let’s take a look at 15 reasons why you may be called to redo a blood test.
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Reasons For Repeating a Blood Test
1. Doctor made a mistake on the requisition form
It is not uncommon for a doctor to make a mistake on the form that was given to the patient to take to the lab to do the blood test.
The doctor may have missed a test or selected the wrong test for the patient. After receiving the results from the lab and noticing the error, the doctor may send you back to do the test that was missed.
In a case like that the doctor may explain to you the reason or if not, ask your doctor for an explanation.
2. Patient did not prepare properly for the test
You have to fast for 8 to 12 hours for a fasting blood sugar or lipids test. If you did not fast as were instructed or you were not told to fast and did not, then you will have to repeat the test.
Eating before a glucose or lipids test can affect test results. Your doctor wants to know what the results are after you have fasted for 8 to 12 hours to make correct interpretations of your results.
There are also other blood test for which you may need to fast. Always ask your doctor if you need to fast for a test. Sometimes, they forget to tell you.
3. Test was not done as instructed
If you did not follow the instructions given you by your doctor or the lab to do a particular test, then it may be that you may have to repeat the test.
Not following correctly lab instructions for a particular test can result in erroneous results.
4. Wrong tube was drawn for test ordered
Sometimes, a phlebotomist may make a mistake by filling the wrong tube for the tests ordered or not drawing a needed tube at all. The person will have to be contacted to come back to redo the tests.
Lab testing cannot be done with wrong tubes drawn or missing ones. That will result in erroneous test results. The correct tubes have to be drawn first.
5. Quantity was not sufficient
There are times when a technician may not collect enough blood for a particular test. Certain tests like coagulation need a definite amount of blood. Others need at least 1 ml or more. If blood collected is less than 1 ml, then the individual may have to return to repeat the blood draw.
The collection tube may have had a defect, thus having little vacuum or none at all or maybe the tube was used before. Also, it could be that the technician didn’t know how much blood to collect for that particular test. I wrote an article sharing how much blood to draw for a blood test. Go read it here.
Another reason is if the phlebotomist or nurse had difficulty drawing blood from the person. Sometimes, that results in insufficient blood or a hemolyzed sample.
6. Specimen was hemolyzed
If the sample is hemolyzed, it may be that the person will need to repeat the test or tests. A hemolyzed specimen can cause erroneous results.
A phlebotomist’s technique can cause hemolysis, as well as, if the person from whom the blood is being drawn is moving their arm.
Another reason is if a syringe was used to draw and transfer the blood. If the syringe is not used properly, hemolysis can occur.
7. No labeling of sample
If a specimen is not labeled or the patient name was not written on the tube, then there will be a missing sample for that person’s name. When this happens, the individual will have to be called back to redo the blood draw.
It is Unsafe to assume that a specimen found with no name on it is most likely the patient’s own. Don’t Ever Do that! What if it’s not? It’s best to ask the person to come back to do the blood test. Don’t take any chances.
A simple rule is to label the tube before drawing the blood or to do so after drawing the blood in the presence of the patient.
8. No sample was received
Sometimes, the laboratory may not get a sample for a particular patient. The patient blood was drawn but the specimen was not received.
It may be that the sample was left at the phlebotomy site, it was compromised during transport and handling, or it was left or forgotten some other place.
Depending on what occurred, the specific requirements for storing and handing the sample, and the amount of time that has elapsed a new sample will have to be taken.
9. Sample no longer suitable
Some laboratories send specimens to other laboratories for testing. If there is a delay in the shipping process or some conditions were not met, the samples may no longer be suitable for testing and another blood sample would have to be taken.
Each tests have certain conditions or requirements for storage, handling, and transport. If these requirements are not met, then the specimens will be rejected.
10. Specimen was contaminated or destroyed
Sometimes, an accident may happen at the laboratory or during transport and the sample may become contaminated or destroyed. In such cases, a new specimen is needed for testing.
Inform the patient of the incident and ask them to come back to redo the blood test.
11. Wrong test was done for patient
If the laboratory mistakenly did a test that was not requested by the doctor or missed a test that was requested by the doctor, then another sample may have to be drawn if the previous blood specimen is no longer suitable.
Most times, a laboratory will notice the mistake before the results are sent out. However, sometimes it may go out unnoticed.
12. Your body’s reaction to a new medication
Your doctor wants to tract how your body is reacting to a new medication or therapy. Your doctor may have drawn blood before the medication but will also ask you to do more blood tests over the next few days or so to monitor how you are doing.
This is common with individuals who are on blood thinners. Every week or so they have to do blood tests.
It is also common when a doctor is monitoring therapeutic drug levels. The person blood is drawn at regular intervals in order to measure the amount of drugs in their blood.
13. Abnormality or unexpected results
If a person’s blood test results come back showing test values below or above the normal ranges, the doctor may send you to redo the test or to do some other tests in order to make a correct interpretation of such results.
Borderline test results may not be concerning, so your doctor may decide that no further investigation or treatment is needed.
However, if the results are concerning, more blood tests will be requested. There is no need to panic just go through the process.
14. Anomalous results
If after receiving your blood test results your doctor observes that the results do not match or fit the pattern of your other results and history, then you will be requested to repeat the test.
There may have been something wrong with the test. It may be that an error occurred somewhere in the process of collecting the blood, transporting it to the lab, or while processing it in the laboratory.
To remove any suspicion or to make sure that the results actually reflect your health, your doctor will send you back to redo the test.
15. Confirm a diagnosis
If your doctor has determined that you have contracted a particular disease you will be sent back to repeat a blood test or do other tests in order to confirm the diagnosis.
Related Questions
1. Why do I need a second blood test in 2 weeks? If you are put on a new medication or treatment, your doctor will want to tract your body’s reaction to the new treatment. He/she wants to know if the medication is working or not, if he/she needs to increase or decrease the dose, or give you a different one.
2. Why does my doctor wants more blood tests? Here are several reasons why your doctor has sent you to do more blood tests:
- Your previous results were borderline or unclear
- Your doctor struggled to accurately interpret your test results
- More tests needed to get a full picture of your health
- Some tests require more than one sample
- You may have a health problem