Clinical tests: what they are, what they’re for and when to have them

A complete blood count measures the red blood cells, white blood cells and platelets, providing a comprehensive overview of the blood system. Low red blood cell and haemoglobin counts may indicate anaemia.
High white blood cell counts are common in cases of infection or inflammation.
And if platelet counts are very low or very high, this can indicate a greater risk of haemorrhage or excessive clotting.

Glycemia measures the blood sugar level. Repeatedly high results can indicate diabetes or prediabetes, while sporadic spikes can result from stress, recent food intake or absence of fasting.

This test measures total cholesterol levels, HDL (“good” cholesterol), LDL (“bad” cholesterol) and triglycerides (type of “fat” in blood), which are essential to assess cardiovascular risk. Low levels of HDL and high levels of LDL can increase the risk of heart disease. Triglycerides are associated with diet, a sedentary lifestyle or genetic factors.

The key parameters to assess liver function in clinical tests include AST (aspartate aminotransferase), ALT (alanine aminotransferase) and GGT (gamma-glutamyl transferase), as well as bilirubin, all associated with liver function and health.

Abnormal results may indicate liver inflammation, irritation or overload, possibly related to medication, alcohol consumption, viral infections or metabolic changes.

Kidney function is normally assessed through creatinine and urea levels, which reflect the kidneys’ filtration rate. Changes can result from dehydration, medication or diminished renal function. Age, muscle mass and medical history can influence these results; therefore, they should always be analysed by a specialist.

One of the principal and most widely used inflammatory markers is CRP (C-reactive protein), a substance produced by the liver, which increases when there is inflammation or infection.

These hormones are measured above all to assess thyroid function, focusing primarily on TSH (thyroid-stimulating hormone), T3 (triiodothyronine) and T4 (thyroxine). Changes in levels can indicate hypo or hyperthyroidism (thyroid disorders). This analysis should aways take into account the clinical signs and family history.

Urine tests are used to identify urinary infections, kidney alterations and metabolic conditions. The presence of blood, proteins or leucocytes may suggest infection or inflammation. The pH level and other parameters help complete the assessment.

Stool tests can detect parasites, occult blood and gastrointestinal disorders. Positive results do not necessarily mean serious illness, but may justify further diagnostic measures, such as digestive exams or microbiological tests.

The recommended frequency depends on age, medical history, lifestyle and individual risk factors. Ideally, clinical tests should be performed once a year or as medically advised. However, people suffering from chronic conditions, who take regular medication or exhibit persistent symptoms may require more regular testing, always according to the physician’s guidelines.

Yes, in many cases this is possible, but it is recommended that they be overseen by a physician, since the specialist is able to determine the most suitable parameters for your case and interpret the results accurately. A prescription is only mandatory for specific tests that require clinical supervision.

No, this depends on the type of test. Fasting is only necessary for certain types of tests, especially those that measure glycemia, triglycerides and other metabolic parameters that may be influenced by recent food intake. Other tests, such as blood count, liver function (AST and ALT), kidney function (urea and creatinine), inflammatory markers, many hormone tests and tests for antibodies against infectious agents (immunity testing) or other components in our body (autoimmune disease testing), do not require fasting. The lab always provides information on the requirements.

Collection is quick and causes only slight momentary discomfort. Some people may develop a small bruise that disappears after a few days and does not pose any risk. Overall, laboratory tests are safe and well tolerated. 

Most routine tests (e.g.: blood count, cholesterol or glycemia) are ready in a few hours and delivered on the same day as collection. More specific tests, such as complex hormone testing, microbiological tests or genetic tests, can take longer. Laboratories always provide the expected deadlines.