Laboratory tests: questions and answers that everyone should know

What are laboratory tests?

These are medical tests that are performed on human biological materials — blood, urine, feces, smears, sputum, tissues, etc. They allow doctors to detect inflammatory processes, organ dysfunction, the presence of infections, hormonal or immune failures, as well as predisposition to certain diseases.

What are the laboratory tests?

Laboratory studies are divided into several main groups:

• General clinical: blood, urine, stool analysis

• Biochemical: glucose, liver enzymes, cholesterol

• Immunological: antibodies, immunoglobulins

• Hormonal: thyroid gland, reproductive hormones

• Infectious: detection of viruses, bacteria, fungi

• Genetic: detection of hereditary changes, mutations

• Coagulogram: blood clotting

• Cytology/histology: research of cells, tissues

When does a doctor order laboratory tests?

• When symptoms appear (fever, pain, weakness)

• To clarify the diagnosis

• Before surgery

• To control chronic diseases

• After treatment — check the effectiveness

• During a preventive examination (once a year - recommended for everyone)

What tests should be taken preventively?

• Complete blood count

• General urine analysis

• Biochemistry (liver and kidney parameters, sugar, cholesterol)

• Thyroid hormones (TSH)

• Vitamin D, ferritin - for frequent fatigue

• Hepatitis B and C test (once in a lifetime or at risk)

• PCR for major infections - when planning pregnancy

How to prepare for tests?

• Most tests are passed on an empty stomach (don't eat for 8–12 hours)

• In the morning: no smoking, no coffee, water is acceptable in small quantities

• For 1–2 days: do not drink alcohol, fatty foods

• If you are taking medication, tell your doctor or laboratory technician.

• Important for hormones cycle phase (for women - check with your gynecologist)

What errors can distort the results?

• Failure to follow a diet or drinking alcohol the day before

• Intense physical activity before donating blood

• Independently changing the dosage of medications

• Improper collection of urine, feces, and swabs

• Stress — it can affect hormonal levels

How often do you need to take tests?

• General - annually

• Biochemical - as recommended by a doctor (sometimes every 6 months)

• Hormones - upon complaints or observation

• After 40 years of age - advanced diagnostics (including tumor markers)

Can I get tested without a doctor's referral?

Yes, in most private laboratories you can take any test yourself. But it is important: Interpretation of results should be the responsibility of the doctor., especially if you are not sure how to interpret them.

Table: Examples of laboratory tests by purpose