What Is A Platelet Count Blood Test, And What Do My Results Mean?
A platelet count measures the average platelet level in a person's blood. High or low platelet levels can increase the risk of clotting or excessive bleeding.
Platelets, also called thrombocytes, are fragments of larger cells made in the bone marrow called megakaryocytes. These fragments are crucial to wound healing.
Abnormal platelet levels can lead to various health complications. This article discusses the process of a platelet blood test and what the results mean.
The mean platelet count blood test is typically part of a complete blood count (CBC) test. A CBC reveals important information about the number of different blood cells in the body.
A platelet count test reveals the average number of platelets a person has per microliter of blood.
Doctors can perform the test independently or as part of a CBC test. They will often perform a platelet count test if they suspect a disorder affecting it.
The test involves drawing blood from a vein in the arm or hand.
Obtaining a blood sample from a vein takes a few minutes and generally causes only minimal discomfort. Occasionally, some people may feel queasy or light-headed while the blood is drawn or shortly after. Taking slow deep breaths is usually enough to calm these feelings. Some people may develop a small mark or bruise.
Typically, doctors will send these samples to a lab for assessment and relay results to the patient in due course.
A person's platelet levels can change with age, and certain medical conditions can also affect them.
A platelet count that is too low or too high can lead to health complications. A low platelet count is known as thrombocytopenia, while a high platelet count is known as thrombocytosis.
Tests measure average platelet levels per microliter (mcL) of blood. Below are guideline platelet levels.
A low platelet count can make it difficult for the blood to clot, putting a person at risk of excessive bleeding. Low platelet counts can be due to an inherited medical condition or an acquired medical condition. In some cases, the cause may be unknown.
Risks and complicationsIf the blood platelet count falls below 20,000 per mcL, a person can begin bleeding spontaneously. This is a medical emergency, and people who experience spontaneous bleeding may require a blood, or platelet, transfusion.
Low platelet count increases the risk of death in people who experience a traumatic injury.
A high platelet count can occur when something causes the bone marrow to make too many platelets. When the reason is unknown, it is called primary or essential thrombocytosis.
When excess platelets are due to an infection or other condition, it is called secondary thrombocytosis.
Risks and complicationsA person's blood clots more quickly when they have too many platelets.
Clotting is a natural protection against bleeding. The body produces more platelets during and following an injury.
However, because platelets cause blood clotting, they can also cause dangerous blood clots in the arms or legs. The blood clot may break off or travel to another area of the body.
The risk of a blood clot is higher in people confined to bed by illness or who cannot move their limbs.
Someone who has a high platelet count because of a recent injury but who must remain in bed may need monitoring to reduce the risk of blood clots as a result.
Several factors can cause a person's platelet levels to change. These include acute and chronic medical conditions and age.
Causes of high platelet countsSome temporary conditions can cause a higher-than-normal platelet count. A doctor may order a retest a few days or weeks later if this happens. Some common reasons for high platelet levels include:
If a person's platelet count remains high, chronic medical conditions may be responsible. These may include:
Causes of low platelet countsCommon causes of low platelet volume include:
Platelet count tends to decline with age. A platelet count that is lower than it once was or on the lower end of normal may not be a cause for concern in an older adult — especially if there are no other symptoms.
A person's platelet levels change with age and can alter due to acute injury, medication changes, and deficiencies.
However, excessively high or low platelet levels can indicate the presence of an underlying health condition, infection, or injury.
It is generally not possible, however, to diagnose a medical condition based on platelet count alone. People should talk with a doctor about further testing if a blood test reveals low platelets.
It is advisable to inform the doctor about any other symptoms, which can help narrow down testing options.
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Engineered Platelets Can Induce Anti-inflammatory, Immunosuppressive Response, Finds Scientist
New research led by a St. Michael's Hospital scientist reveals how platelets can inhibit inflammation and immune responses. The discovery, published in the journal Research, constitutes a fundamental re-understanding of platelets and could lead to potential therapies to treat autoimmune and alloimmune diseases, says Dr. Heyu Ni, a scientist at the Keenan Research Center for Biomedical Sciences.
Platelets are small blood cells that form clots to stop or prevent bleeding. Conventional thinking is that platelets contribute to inflammation and immunity. Chronic inflammation is bad for our health, and an overactive immune system—when the body triggers an immune response when there is no threat– can lead to autoimmune disorders such as multiple sclerosis, arthritis, lupus and type 1 diabetes.
An overactive immune response may also lead to alloimmune diseases and conditions such as allergies and failed organ transplants and blood transfusions.
"Traditional thinking of platelets is that they are pro-inflammation and pro-immunity, but we discovered, surprisingly, that they can do the opposite—they can inhibit inflammation and inhibit an immune response," said Ni. "This completely shifts our understanding of how platelets behave—a possible switch from foe to friend."
June Li and other trainees in Ni's lab made the discovery by immunizing mice that are missing two proteins: GPIbα and GPIIbIIIa. These proteins, both critical for stopping bleeding, are found on the surface of normal platelets.
The team immunized mice who lack these two proteins with normal platelets, expecting their immune systems to generate antibodies against GPIbα and GPIIbIIIa. They found that the mice struggled to generate antibodies against GPIbα. The team hypothesized this was because GPIbα has many sugars on its surface, making it difficult for the immune system to recognize it. The team then removed a part of these sugars, believing that by altering the sugars, they mice would recognize the protein and generate more antibodies.
The team unexpectedly found that these altered platelets—called desialylated platelets—did not result in more antibodies, but rather decreased antibody generation. They also found that the desialylated platelets were cleared from the body by the liver—not the spleen, where platelets are usually cleared.
After the platelets were cleared by the liver, cells called Kupffer cells generated an immunosuppressive and anti-inflammatory response in the mice. As platelet desialylation and clearance naturally occurs for all aged platelets in our bodies, this anti-inflammatory response may provide a daily preventive mechanism against many autoimmune diseases, said Ni.
Through pre-transfusion testing in mice, the team further found that desialylated platelets can also decrease the immune responses against non-platelet antigens. The team infused the mice with sheep red blood cells and coagulation factor VIII, a blood-clotting protein missing in people with hemophilia A.
Hemophilia A patients—who are at risk of excessive bleeding in injuries or after surgery—can be given factor VIII via infusion, but there is a risk that their immune system may produce antibodies against it. Engineered desialylated platelets could reduce the immune response and reduce this risk, said Ni.
Ni, also a senior scientist of Canadian Blood Services, said the discovery has important implications for autoimmune and alloimmune diseases, including cancer immunology, organ transplantation, and transfusion medicine.
"This type of transfusion with engineered desialylated platelets may be further developed to control lupus, arthritis and Type 1 diabetes and be beneficial in organ and tissue transplants," he said. "We don't know yet the full extent of the impact, but the potential opportunity is huge."
More information: June Li et al, Desialylated Platelet Clearance in the Liver is a Novel Mechanism of Systemic Immunosuppression, Research (2023). DOI: 10.34133/research.0236
Citation: Engineered platelets can induce anti-inflammatory, immunosuppressive response, finds scientist (2023, October 6) retrieved 9 October 2023 from https://medicalxpress.Com/news/2023-10-platelets-anti-inflammatory-immunosuppressive-response-scientist.Html
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Understanding The Stages Of Dengue Infection For Timely Detection And Treatment
Cleared waste piled up near a manhole in the center of the road at Padmaraonagar. This is causing danger to motorists. (Image: S.Surender Reddy)
Hyderabad: Amid an ongoing surge in viral fevers and influenza cases in the city, doctors called for the timely detection of dengue by understanding the various stages of the infection for the right treatment.
Dengue infection has an incubation period of around seven days after being bitten by the infected Aedes aegypti mosquito, which is active only during the daytime.
Doctors said that dengue progresses in two stages, first the fever phase — with symptoms of high-grade fever, body pain, joint pain and vomiting — and the advanced stage of the infection, also referred to as the critical stage, which could lead to dengue shock syndrome and subsequent fatality.
Dr Hari Kishan Boorugu, a consultant physician at a leading private hospital, said, "The fever phase is for 2-7 days where a patient experiences fever, body pain, weakness, vomiting, headache. This phase requires symptomatic treatment and more than 80 per cent of patients go into recovery phase after treatment in this phase. The critical stage begins when although the fever comes down, the patient experiences warning signs and symptoms. This phase usually comes after three to five days of the fever phase."
The critical phase warning symptoms, doctors said, were severe abdominal pain, bleeding in nose and gums, extreme weakness, haemoconcentration, petechiae rash, excess vomiting and severe headache.
"Dengue recovery needs rest and lot of fluids in addition to prescribed medication. However, in certain cases in the critical phase, when the patient experiences rapid decline in the platelets, dengue shock syndrome with multiple organ failures, sudden drop in the blood pressure, jaundice, brain and kidney function failure can need admission and monitoring," said Dr Hari Kishan.
Doctors further said that dengue deaths were a result of disseminated intravascular coagulation (DIC), known as dengue haemorrhagic fever (DHF), multiple organ failure, liver or kidney failure and dengue encephalitis.Another important aspect of dengue is the platelet count, which would fall due to the infection. However, a critical stage would only be considered when the count ranged between 10,000 and 15,000, and only a rapid decline in the count would be a determining factor of the severity of dengue.
Dr Anish Ananad, consultant (internal medicine), emphasised the need for proper testing.
"A suspected case needs to take NS1 and IGM tests in the first seven days of the infection. Once the dengue is confirmed, we then ask the patient for a blood picture for haemoglobin and platelets, Liver Function Test (LFT) and creatinine test. If the platelet count is above one lakh, the blood picture is repeated after one week. However, if the platelets near a critical stage of 10,000, tests are conducted every alternate day," said Dr Anish.
"I would advise that if the high-grade fever persists for more than 3-5 days, then it is advisable to visit a physician for the right and timely diagnosis of dengue. Delayed diagnosis could put patients in a critical stage," he said.
He stressed that there was no need to panic and rush for multiple tests as the recovery rate for dengue was more than 98 per cent, saying strong immunity was the most important factor in combating dengue.
Doctors, however, advised more precautions for schoolchildren, pregnant women, elderly and patients with comorbidities.
