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Tests before surgery: which tests are important and why they are prescribed
Preparation for surgery is an important stage that helps the doctor assess the patient's health, predict possible risks, and choose the safest surgical tactics. Even if the patient feels well, the body may have hidden features that affect the course of the operation or anesthesia.
That is why before each planned operation, a complex of laboratory tests and instrumental examinations is mandatory.
Why is it important to take tests before surgery?
The analyses allow us to assess:
• the work of internal organs
• risk of bleeding
• blood clotting
• presence of inflammation or infection
• hemoglobin level and oxygen supply
• condition of the cardiovascular system
• the body's reaction to anesthesia
This is necessary so that the operation goes without complications and the recovery period is as safe as possible.
What tests are standard before a planned operation?
The list of examinations may vary depending on age, chronic diseases, and type of surgery. However, there are basic tests that are prescribed to almost everyone.
The most common studies:
• Complete blood count
• Biochemical blood test
• Coagulogram
• Blood type and Rh factor
• Blood glucose
• Urine analysis
• Tests for hepatitis B and C, HIV, syphilis
• ECG
• Fluorography or chest X-ray
Additional tests may be added for patients with chronic conditions.
Table: mandatory tests before surgery and why they are needed
| Analysis | What does it show? | Why is it important before surgery? |
|---|---|---|
| Complete blood count | hemoglobin, leukocyte, platelet levels | detection of anemia, inflammation, risk of bleeding |
| Blood biochemistry | liver, kidneys, electrolytes | assessment of the functioning of organs that affect anesthesia |
| Coagulogram | blood clotting | risk of bleeding or thrombosis |
| Blood type, Rh factor | individual parameters | necessary in case of blood transfusion |
| Glucose | blood sugar | control of the risk of complications during anesthesia |
| Urine analysis | kidney condition, infections | important for antibiotic selection |
| Hepatitis, HIV, syphilis | viral infections | affects treatment tactics and personnel safety |
| ECG | heart rate | identifies anesthesia risks |
| X-ray / fluorography | lung condition | important for anesthesia and ventilation |
Additional tests that may be prescribed
In some cases, the doctor prescribes additional examinations:
• thyroid hormones (TSH, T4)
• ferritin and iron
• inflammatory markers (CRP)
• Ultrasound of the abdominal organs
• echocardiography
• coagulation tests (D-dimer)
• PCR tests for suspected viral infections
This depends on the upcoming surgery and the patient's health condition.
Tests before surgery under general anesthesia
If general anesthesia is planned, special attention is paid to:
• heart (ECG, sometimes echocardiography)
• lungs (X-ray or fluorography)
• level hemoglobin
• liver and kidney function
The anesthesiologist uses this data to select a safe drug and dosage.
How long are test results valid?
Usually:
• general and biochemical tests — 10–14 days
• coagulogram — 7–10 days
• fluorography — up to 1 year (if there are no symptoms)
• ECG — 2–4 weeks depending on age
• infection tests — 1–3 months
But the final deadline depends on the requirements of the medical institution.
Do I need to prepare for the tests?
Yes, proper preparation affects the accuracy of the result.
The patient is recommended to:
• to come on an empty stomach (8–12 hours without food)
• avoid alcohol and fatty foods the day before the tests
• do not overwork yourself before the day of the examination
• inform the doctor about all medications taken
• drink enough water
If the patient is taking drugs that affect blood clotting (aspirin, anticoagulants), the doctor may change the regimen.
When to see a doctor before taking tests
If you have:
• cold symptoms
• high temperature
• exacerbation of chronic diseases
• high blood pressure
• unusual pain or weakness
— be sure to notify your doctor. Some surgeries may be postponed until your condition stabilizes.
Comprehensive tests before surgery are not a formality, but an important safety step. They help the doctor see the full picture of health and choose the best treatment option, and the patient feel calmer and more confident in the outcome.
