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Blood Tests

Blood tests help doctors check for certain diseases and conditions. They also help check the function of your organs and show how well treatments are working.

PubMed Health Glossary
(Source: NIH - National Heart, Lung, and Blood Institute)

Blood Tests

Blood tests help doctors check for certain diseases and conditions. They also help check the function of your organs and show how well treatments are working.

Specifically, blood tests can help doctors:

Overview

Blood tests are very common. When you have routine checkups, your doctor may recommend blood tests to see how your body is working.

Many blood tests don't require any special preparations. For some, you may need to fast (not eat any food) for 8 to 12 hours before the test. Your doctor will let you know how to prepare for blood tests....Read more about Blood Tests
NIH - National Heart, Lung, and Blood Institute

What works? Research summarized

Evidence reviews

Blood tests for the diagnosis of pancreatic necrosis (pancreatic destruction due to inflammation of pancreas)

The pancreas is an organ in the abdomen (tummy) that secretes several digestive enzymes (substances that break down the food that we eat) into the pancreatic ductal system, which empties into the small bowel. The pancreas also contains the islets of Langerhans, which secrete several hormones including insulin (which helps regulate blood sugar). Acute pancreatitis is a sudden inflammation of the pancreas that can lead to destruction of the pancreas (pancreatic necrosis). The treatment of people with pancreatic necrosis differs from that of people without pancreatic necrosis. Blood tests such as C‐reactive protein (CRP), procalcitonin, and lactate dehydrogenase (LDH) may be used to find out whether a person with acute pancreatitis has pancreatic necrosis. This is usually followed by CT scan to confirm that the person has pancreatic necrosis. If the person is found to have pancreatic necrosis, the intensity of care is increased and additional treatments are performed as required. At present it is unclear whether measuring the levels of CRP, procalcitonin, or LDH is useful in identifying pancreatic necrosis.

Does employing general practitioners to provide care for patients with non‐urgent problems in emergency departments decrease resource use and costs?

An important portion of patients who attend hospital emergency departments (EDs) present with health problems that are classified as non‐urgent. With many EDs experiencing long‐waits and overcrowding, it has been suggested that providing primary care services in EDs for patients with non‐urgent problems may be an efficient and cost‐effective alternative to emergency care.

Venepuncture versus heel lance for blood sampling in term neonates

In most countries, a blood sample from newborn babies is needed for screening tests. A heel lance is the standard way of taking blood, but it is a painful procedure with no optimal method of pain relief known. This review of trials found evidence that venepuncture, when done by a trained practitioner, caused less pain than heel lance. The use of a sweet tasting solution given to the baby prior to the event reduced pain further. The evidence included outcome measures using pain scales, how long the baby cried and how the mother rated their baby's pain.

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Summaries for consumers

Blood tests for the diagnosis of pancreatic necrosis (pancreatic destruction due to inflammation of pancreas)

The pancreas is an organ in the abdomen (tummy) that secretes several digestive enzymes (substances that break down the food that we eat) into the pancreatic ductal system, which empties into the small bowel. The pancreas also contains the islets of Langerhans, which secrete several hormones including insulin (which helps regulate blood sugar). Acute pancreatitis is a sudden inflammation of the pancreas that can lead to destruction of the pancreas (pancreatic necrosis). The treatment of people with pancreatic necrosis differs from that of people without pancreatic necrosis. Blood tests such as C‐reactive protein (CRP), procalcitonin, and lactate dehydrogenase (LDH) may be used to find out whether a person with acute pancreatitis has pancreatic necrosis. This is usually followed by CT scan to confirm that the person has pancreatic necrosis. If the person is found to have pancreatic necrosis, the intensity of care is increased and additional treatments are performed as required. At present it is unclear whether measuring the levels of CRP, procalcitonin, or LDH is useful in identifying pancreatic necrosis.

Does employing general practitioners to provide care for patients with non‐urgent problems in emergency departments decrease resource use and costs?

An important portion of patients who attend hospital emergency departments (EDs) present with health problems that are classified as non‐urgent. With many EDs experiencing long‐waits and overcrowding, it has been suggested that providing primary care services in EDs for patients with non‐urgent problems may be an efficient and cost‐effective alternative to emergency care.

What kinds of allergy tests are there?

Various tests can be used to find out what kind of substance is causing an allergic reaction: skin tests, blood tests and challenge tests. Your doctor will usually decide which test to use based on your description of the symptoms and your medical history.

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Terms to know

Blood
A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.
Blood Plasma
The clear, yellowish, fluid part of the blood that carries the blood cells. The proteins that form blood clots are in plasma.
Bone Marrow
The soft, sponge-like tissue in the center of most bones. It produces white blood cells, red blood cells, and platelets.
Enzymes
Protein made by the body that brings about a chemical reaction - for example, the enzymes produced by the gut to aid digestion.
Erythrocytes (Red Blood Cells)
A cell that carries oxygen to all parts of the body.
Hematocrit
A measure that tells what portion of a blood sample consists of red blood cells. Low hematocrit suggests anemia or massive blood loss.
Hemoglobin
A protein inside red blood cells that carries oxygen from the lungs to tissues and organs in the body and carries carbon dioxide back to the lungs.
Leukocytes (White Blood Cells)
A type of immune cell. Most white blood cells are made in the bone marrow and are found in the blood and lymph tissue. White blood cells help the body fight infections and other diseases. Granulocytes, monocytes, and lymphocytes are white blood cells.
Platelets (Thrombocytes)
A tiny piece of cell that is made by breaking off of a large cell in the bone marrow. Platelets are found in the blood and spleen. They help form blood clots to slow or stop bleeding, and to help wounds heal. Also called thrombocyte.
Triglycerides
One of the major forms of fat that is produced in the liver and found in the blood.

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Other terms to know: See all 10
Blood, Blood Plasma, Bone Marrow

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