Bleeding time

The bleeding time depends largely on the normal function of platelets and small blood vessels and their ability to form a clot at the site of vessel damage. The bleeding time is considered to be the oldest and simplest test used to assess platelet function.

What is bleeding time?

The bleeding time is considered to be the oldest and simplest way to assess the function of platelets. There are several factors that can affect bleeding time such as diet and race. It depends mainly on the proper function of platelets and small blood vessels and their ability to form a clot at the site of vessel damage. Bleeding time is the time from the time of standardized skin injury to the end of bleeding, which allows for an initial assessment of in vivo haemostasis

What are the functions of platelets?

Platelets are small discoidal cells, their small size and shape allow them to move along the sides of the vessels that they can “control”. The platelets respond very quickly to these reactions by forming a clot that blocks the injured area and prevents bleeding. Any abnormalities in platelet function can result in bleeding of varying clinical severity. Platelets play an important role in the following cases:

1. homeostaza,
2. vessel regeneration,
3. inflammatory processes,
4. thrombosis.

When do we do the bleeding time test?

Bleeding time testing is recommended in the following cases:

1. Abnormal, prolonged bleeding, formation of extensive bruises and hematomas after impact.
2. Suspected impairment of the number and function of platelets.
3. Suspicion of vascular diathesis.
4. Assessment of the effects of taking medications.

Factors influencing bleeding time disorders

Among the factors affecting the bleeding time, we can mention:

1. vitamin C deficiency,
2. alcohol poisoning,
3. liver failure
4. taking medications (aspirin, non-steroidal anti-inflammatory drugs, antibiotics – penicillin or antidepressants).

Bleeding time – examination

1. Preparation for the bleeding time test: on an empty stomach (at least 8 hours).
2. The course of the study: the Ivy method – a single incision of the forearm skin with a length and depth of 3 mm.
3. Time of waiting for the result: 1 day.
4. Standard: 1-4 minutes.

Comments: The test is not very repeatable, i.e. the results of the determinations obtained from the same blood sample may differ when the measurement is repeated in different laboratories. Besides – it is difficult to conduct further tests under the same conditions. The way the test is performed by the laboratory technician also has a great influence on the result. Due to the difficulty of reproducibility, bleeding time determination is currently rarely used in clinical practice.

Types of methods for measuring bleeding time

The methods of measuring platelets can be divided into:

1. immunological – where specific antibodies are used;
2. biochemical chromogenic;
3. molecular diagnostics;
4. general – functional (assessment of vessels and platelets);
5. general – coagulometric (coagulation assessment).

Under what circumstances is the bleeding time prolonged?

1. Primary and secondary thrombocytopenia
2. leukemia,
3. uraemia,
4. cirrhosis,
5. some infectious diseases,
6. von Willebrand syndrome,
7. vascular blemishes.