Can Antibiotics Affect Blood Tests? What You Need to Know!
Are you considering health tests while on antibiotics? You must have a question in your mind, ‘Can antibiotics affect blood tests? Here is the complete insight to clear your confusion regarding the possible impact of antibiotics on your blood test results and common antibiotics that can alter your test reports.
A recent study published in the Journal of Ecohumanism in 2024 indicates a significant impact of antibiotics on diagnostic test results, particularly blood cultures, inflammatory markers, and Renal or Liver Function Tests, thus highlighting the possible connection.
Therefore, it is necessary to consult your doctor before undergoing a blood test or wait for at least 2 weeks after completing a course of antibiotics.
Do Antibiotics Interfere with Blood Test Results?
Not all antibiotics affect blood test results, but certain types, such as Beta-lactams, Vancomycin, and Cephalosporins, can alter them. Their interference may lead to inaccurate lab readings and potentially delay the correct diagnosis and treatment plan. Additionally, some antibiotics have immunomodulatory effects that can temporarily hide signs of infection or inflammation in the body.
How do Antibiotics Affect Blood Tests?
Antibiotics can interfere with blood test results in various ways, resulting in misleading outcomes. The extent of this interference, however, depends on the type of antibiotic, the timing of the test, and the specific biomarkers being measured. Some common ways by which an antibiotic can give a false positive or negative test result are mentioned below:
Suppresses the Bacterial Growth
One of the most common reasons for false test results while taking antibiotics is the temporary suppression of bacterial growth. It can lead to false-negative results, especially in blood culture, which is misleading for both the patient and the healthcare provider.
Changes the Level of Certain Biomarkers
Some antibiotics can alter the normal level of biomarkers in the blood, resulting in inaccurate test interpretations. Bilirubin, creatinine, and blood glucose are the most common markers that can be affected by antibiotics.
Immunomodulatory Effect
Some antibiotics have mild immunosuppressive properties. They may lower the level of infection or inflammation markers (such as CRP or white blood cell count), which can hide the signs of an ongoing condition.
List of Common Antibiotics that Can Alter the Test Results
Certain antibiotics can affect the accuracy of blood test results by altering the levels of specific biomarkers. This interference can lead to misinterpretation of a patient’s health condition, causing risks. Below is a list of commonly used antibiotics that may have an impact on the lab values:
Cefalotin
Cefalotin can significantly increase serum creatinine levels in the body, which can be misunderstood by the healthcare team as a sign of renal disease. To confirm if the rise in creatinine is due to antibiotic usage, a comprehensive Kidney Function Test may be needed.
Ceftriaxone
While on Ceftriaxone, patients may see a rise in bilirubin levels in their blood reports, falsely indicating a liver dysfunction. Liver screening may help to identify whether the bilirubin increase is due to Ceftriaxone or an underlying liver disease.
Cefpirome & Cefazolin
Both Cefpirome and Cefazolin antibiotics can raise the creatinine level in the blood, potentially leading to a false positive indication of a kidney disorder.
Amoxicillin
Amoxicillin can show a false positive diabetes in blood tests by indicating a false rise in the glucose level in blood. To confirm the reason, you may check your blood sugar level at home or get tested for HbA1c at your nearest clinic.
Erythromycin & Cotrimoxazole
Erythromycin can detect a false increase in prothrombin time (PT) and the International Normalized Ratio (INR), which can be misleading for your healthcare advisor.
Ciprofloxacin & Levofloxacin
Ciprofloxacin and Levofloxacin have been observed to disturb the blood glucose level, which can be misinterpreted as diabetes or abnormal glucose management.
Conclusion
Antibiotics can indeed affect blood tests by interfering with bacterial cultures, altering liver enzymes, or suppressing immune responses, potentially leading to inaccurate or delayed diagnoses. If you’re currently on antibiotics or planning a blood test, it’s important to consult a healthcare professional about timing and test type.
At The National Blood Test Clinic UK, we offer both home blood test kits and clinic-based blood testing to suit your convenience and medical needs. Book your test today and get accurate results, whether you choose testing from home or visiting one of our nationwide phlebotomy centres.
Frequently Asked Questions
Can antibiotics affect STIs test results?
Sexually Transmitted Infections (STIs) are typically treated with antibiotics. If you are currently getting antibiotic treatment for an STI, it is recommended to wait at least four weeks before getting tested to ensure the accuracy of results.
Can antibiotics affect blood culture results?
Yes, antibiotics can affect blood culture results. If you’re on antibiotics or have just completed a course, it is advisable to wait for a specific period (typically 2-4 weeks) before getting tested for blood culture.
Can antibiotics affect thyroid blood tests?
Yes, some antibiotics can affect thyroid test results by altering the thyroid gland's efficiency.
What type of drugs can alter the blood test results?
Certain drugs, such as antidepressants, antipsychotics, and mood stabilizers, can interfere with blood test results, leading to false or misleading outcomes. These medications can affect hormone levels, liver enzymes, and other biomarkers, potentially distorting the accuracy of diagnostic tests.