What Is a PLT Blood Test?

Submitted on March 27, 2012

The PLT blood test is also known as the platelet blood test or a platelet count. PLT in blood test stands for 'platelet'. PLT testing is done to count how many blood platelets there are in our blood. The number of platelets in one microliter of blood can range from 150,000 to 400,000.

Function of Platelets

Platelets help the blood to clot. Platelets are plate-shaped cells which are formed in the bone marrow, and slowly released into the bloodstream. They have a protein on their surface, which helps the cells to stick to each other, and to walls of blood vessels. This helps the blood to clot and stop flowing after an injury.

If the levels of platelets fall very low (below 20,000 in a microliter), the blood cannot clot easily, leading to greater blood loss. Extremely low levels of platelets can even lead to spontaneous bleeding, which can be a life-threatening situation.

On the other hand, if the levels of platelets are too high, they may stick to each other in clumps (or clots), causing blockage in a blood vessel. This can even lead to death by thrombo-embolism.

Reason Why It is Conducted?

If a person is suffering from unexplained bleeding, or if bleeding from even minor wound does not stop easily, or if there are unexplained bruises on the body, a doctor may order a plt lab test.

  • A plt test may indicate bone marrow diseases such as cancer of the bone marrow or leukemia. The increasing number of cancer cells crowd out the bone marrow cells (platelets) leading to a low level of platelets.
  • Decreased platelet counts are also found in patients who have chronic bleeding ulcers in the stomach, or other chronic bleeding problems.
  • Low plt blood test results may also be an indication of certain auto-immune disorders such as idiopathic thrombocytopenia or lupus, which also have low platelets count, since the body's immune system creates antibodies which attack its own organs.
  • Patients undergoing radiation and chemotherapy also have low platelet counts, as do persons who are taking drugs such as digoxin, sulfa drugs, valium, nitroglycerine or quinidine.
  • Certain renal diseases can also lead to a decrease in blood platelets.


It is performed like any other blood test, by puncturing a vein in the inner elbow, taking out the blood and sending it for testing in the lab.

Blood is used as a medium to transport various substances around the body. These substances include nutrients, waste products and a variety of different hormones and chemicals. The blood itself has structures present within it that enable its normal functioning. Medical research has led to the understanding of various typical ranges within which these structures or substances must fall. Platelets are amongst the various substances present in the blood. A platelets blood test is used to determine the amount of platelets found in the blood. The quantity of platelets is just one of the aspects of a complete blood count test. The complete blood count test is one of the most basic tests used for medical analysis. This gives a basic picture of the health of the individual.

Normal Range, Levels and Results of PLT Blood Test

The primary function of the platelets is related to the clotting of blood. After an injury has occurred it is important for the blood to begin clotting. This allows the wound to be sealed and will prevent the further leakage of blood from the wound. Individuals who have low PLT blood test levels may suffer from bleeding disorders where even the tiniest of wounds results in a large quantity of blood being lost. In extreme cases, low PLT blood test levels can result in the individual experiencing spontaneous bleeding. This is actually a condition where microscopic cuts may begin to leak blood. Normally, the platelets are designed to bond with each other so that the wound gets sealed. This does not happen when there is an abnormally low level of platelets.

Similarly, a high PLT blood test result indicates that there are too many platelets in the body. This will lead to a situation where blood clots even at times when there is no requirement to do so. Clots are normally supposed to form around external or internal injuries. Sometimes, these injuries could occur as a result of some infection which causes damage to the cells of the body.

Excessive clotting itself is a dangerous condition as this could lead to a large clot developing. When such a clot develops, it raises the risk of the individual suffering from blood vessel blockage. Blood clots can also jam the flow of blood in the heart which would result in a serious cardiac event.

The platelets blood test is conducted in the same way as a standard blood test. A sample of blood is drawn from a vein in the upper forearm. This blood is then sent to a laboratory where it is analyzed using chemical analysis as well as microscopic analysis.

The PLT blood test lab results should then be analyzed by your doctor to check the PLT blood test range. The amount of platelets in the sample can be used to determine the concentration of platelets in the body. The PLT blood test normal range is between 1,50,000 and 4,50,000 platelets per microliter of blood.

The platelets blood test is thus one of the many different tests that are routinely performed on a sample of blood. The functioning and quantity of platelets in the blood is useful when one wishes to determine why an individual is suffering from a particular medical condition. It is also interesting to note that some individuals with high PLT blood test results may not experience clotting and may yet suffer from bleeding disorders. This occurs when the platelets themselves are of poor quality and do not have the 'sticky' nature that they are supposed to which allows them to bind to one another. This occurs in people who suffer from excessive platelet production as the body is unable to ensure that the platelets are produced with good quality.