We are equipped to provide full screening

Blood analysis

Anàlisi de sang a Vall d'Hebron

Blood tests are one of the most frequent medical tests. They involve taking a blood sample from the patient that is then analysed in a laboratory.

Hospital o serveis complementaris relacionats

Cross-departmental services

Where to find it


What is it for?

Information about the composition of the patient’s blood can be used for many different purposes. For this reason, not all the components of the sample are ever analysed, but rather those components that the doctor decides are useful, depending on the signs and symptoms the patient presents or what they need to know about the patient’s state of health. Blood tests can be requested to:

  • Confirm or rule out a particular health problem or illness.
  • Find out how a patient suffering from a disease is progressing and reacting to treatment. For example, cholesterol checks or tracking chemotherapy treatment.
  • Check a person's general health status to detect illnesses early on. For example, medical check-ups.

The most commonly used parameters in blood tests offer an overall view of the patient’s health status using different indicators:

  • Haemogram: tells us if there is anaemia or infections
  • Kidney function
  • Liver function
  • Fats in the blood, such as cholesterol
  • Existence of infectious or inflammatory processes

There are specific studies that should be carried out depending on each specific case, for example immunological studies, genetic analysis, etc.


How does it work?

Taking the blood sample is simple, the healthcare professional just needs to puncture a patient’s vein with the right type of calibre needle, depending on the patient, and fill the prepared tubes, depending on what needs to be analysed.

The puncture is usually done on the inside of the elbow, and, before doing so, the nurse places a compressor on the arm, normally a rubber band, so that the blood vessels fill up and the blood can be taken more easily. Sometimes it is difficult to puncture this area and alternative locations are used, such as the back of the hand and, especially in children, feet and neck and groin veins.

Once the professional has decided where to make the puncture, it must be cleaned with antiseptic solution before the needle is inserted.

In some cases, patients need to remain still during the extraction, but this is not always necessary. It all depends on the type of analysis required.



Although complications are not usual, some may occasionally occur:

  • Dizziness
  • Bruising in the area where the needle is inserted



There are no alternatives for taking blood samples.

Related professionals
Dra. Pilar
Reimundo Díaz -Fierros
Clinical Laboratories
Sra. Sandra
Prats Vázquez
Clinical Laboratories