Hematologic Examination: Introduction

A hematologic examination is the microscopic examination of the cells of the blood or blood-forming tissues (especially bone marrow), looking for changes in the structure of and/or numbers of various types of blood cells, including immature cells.

There are three main types of blood cells-erythrocytes, leukocytes, and thrombocytes (platelets)-all suspended in a fluid portion called plasma.

Procedures for obtaining blood for a complete blood count include

  • Fingerstick method
  • Venipuncture
  • Bone marrow aspiration
  • Bone marrow biopsy

Sub-section Topics

Definitions

Red Blood Cells

A type of blood cell that is made in the bone marrow and found in the blood. Red blood cells contain a protein called hemoglobin, which carries oxygen from the lungs to all parts of the body. Checking the number of red blood cells in the blood is usually part of a complete blood cell (CBC) test. It may be used to look for conditions such as anemia, dehydration, malnutrition, and leukemia. Also called erythrocyte and RBC.

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. Testing for the amount of hemoglobin in the blood is usually part of a complete blood cell (CBC) test.

Hematocrit

The amount of whole blood that is made up of red blood cells. It depends on the number and size of red blood cells. A hematocrit test is usually part of a complete blood count (CBC). It may be used to check for conditions such as anemia, dehydration, malnutrition, and leukemia. Also called HCT.

White Blood Cells

A type of blood cell that is made in the bone marrow and found in the blood and lymph tissue. White blood cells are part of the body’s immune system. They help the body fight infection and other diseases. Types of white blood cells are lymphocytes (T cells and B cells), granulocytes (neutrophils, eosinophils, and basophils), and monocytes.

Leukocytes

A type of blood cell that is made in the bone marrow and found in the blood and lymph tissue. Leukocytes are part of the body’s immune system. They help the body fight infection and other diseases. Types of leukocytes are granulocytes (neutrophils, eosinophils, and basophils), monocytes, and lymphocytes (T cells and B cells). Checking the number of leukocytes in the blood is usually part of a complete blood cell (CBC) test. It may be used to look for conditions such as infection, inflammation, allergies, and leukemia. Also called WBC and white blood cell.

Granulocytes

A type of immune cell that has granules (small particles) with enzymes that are released during infections, allergic reactions, and asthma. Neutrophils, eosinophils, and basophils are granulocytes. A granulocyte is a type of white blood cell. Also called granular leukocyte, PMN, and polymorphonuclear leukocyte.

Monocytes

A type of immune cell that is made in the bone marrow and travels through the blood to tissues in the body where it becomes a macrophage. Macrophages surround and kill microorganisms, ingest foreign material, remove dead cells, and boost immune responses. A monocyte is a type of white blood cell and a type of phagocyte.

Platelets

A tiny, disc-shaped piece of cell that is found in the blood and spleen. Platelets are pieces of very large cells in the bone marrow called megakaryocytes. They help form blood clots to slow or stop bleeding and to help wounds heal. Having too many or too few platelets or having platelets that don’t work as they should can cause problems. Checking the number of platelets in the blood may help diagnose certain diseases or conditions. Also called thrombocyte.

Anemia

A condition in which the number of red blood cells is below normal.

Aplastic Anemia

A condition in which the bone marrow is unable to produce blood cells.

Leukemia

Cancer that starts in blood-forming tissue, such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the bloodstream.

Leukocytosis

An increase in the number of leukocytes in the blood.

Leukopenia

A condition in which there is a lower-than-normal number of leukocytes (white blood cells) in the blood.

Polycythemia

A disease in which there are too many red blood cells in the bone marrow and blood, causing the blood to thicken. The number of white blood cells and platelets may also increase. The extra blood cells may collect in the spleen and cause it to become enlarged. They may also cause bleeding problems and make clots form in blood vessels.

Thrombocytopenia

A condition in which there is a lower-than-normal number of platelets in the blood. It may result in easy bruising and excessive bleeding from wounds or bleeding in mucous membranes and other tissues.

Bone Marrow Studies

Bone marrow is the soft, sponge-like tissue in the center of most bones. It produces white blood cells, red blood cells, and platelets (https://www.cancer.gov/). The examination of bone marrow can aid in the diagnosis and management of a wide variety of hematologic disorders like lymphoma and leukemia.

Bone marrow can be obtained for examination by

  • Bone marrow aspiration
    • A procedure in which a small sample of bone marrow is removed, usually from the hip bone, breastbone, or thigh bone. A small area of skin and the surface of the bone underneath are numbed with an anesthetic. Then, a special wide needle is pushed into the bone. A sample of liquid bone marrow is removed with a syringe attached to the needle. The bone marrow is sent to a laboratory to be looked at under a microscope. This procedure may be done at the same time as a bone marrow biopsy. Bone marrow aspiration is considered as positive histologic finding in the cancer abstract.
  • Bone marrow biopsy
    • A procedure in which a small sample of bone with bone marrow inside it is removed, usually from the hip bone. A small area of skin and the surface of the bone underneath are numbed with an anesthetic. Then, a special, wide needle is pushed into the bone and rotated to remove a sample of bone with the bone marrow inside it. The sample is sent to a laboratory to be looked at under a microscope. This procedure may be done at the same time as a bone marrow aspiration.
  • Open surgical biopsy
    • The removal of tissue by a surgeon for examination by a pathologist. The pathologist may study the tissue under a microscope.

Bone marrow biopsies are further discussed in Histologic Examination section.

Blood Serum Studies

Automation and modern advances in medical technology enable the physician to obtain a complete battery of laboratory tests from the patient's blood. A cancer abstract can include several data items that require a cancer registrar to enter laboratory values. A cancer registrar should be keenly aware of what tests are needed to complete the abstract. As the field of oncology medicine continues to grow physicians are looking more closely at laboratory tests to aid in the diagnosis and treatment of cancer.

Some studies a physician may order when a cancer is suspected:

Serum Calcium

Calcium circulated in the blood in equilibrium with the calcium in the bone. Patients with cancer have a tendency to develop an excess of calcium in the blood (hypercalcemia), particularly with lung and breast cancers, reflecting metastatic disease of the bone. When bone is replaced with malignant cells, calcium is released in an increased amount in the blood circulation. Normal values are 8.5-10.5 mg/100 ml (slightly higher for children).

Serum Alkaline Phosphatase

Alkaline phosphatase is an intercellular enzyme which becomes elevated when there is destruction of cells. The key areas where it is produced are the liver and bones. An elevated alkaline phosphatase is indicative of bone and liver abnormalities.

Serum Acid Phosphatase

Elevated serum levels of acid phosphatase are seen in patients with carcinoma of the prostate that has extended beyond the prostatic capsule. Patients with prostatic carcinoma still confined within the capsule usually have a normal serum acid phosphatase level. However, patients with benign prostatic hypertrophy may have slight elevations of the serum acid phosphatase level after vigorous prostatic "massage". Since other tissues may also release acid phosphatase into the blood serum, minor elevations may reflect an origin other than the prostate. Serum acid phosphatase studies have been used diagnostically to help determine the resectability of prostatic cancers. Cancers which have extended beyond the prostatic capsule, i.e., to the bone, are not generally treated by prostatectomy.

There are different methods for determining the alkaline phosphatase and acid phosphatase levels in the blood. A cancer registry should be familiar with the methods employed at their facility in order to understand the patient’s test results.

Other Laboratory Studies

Marrow Acid Phosphatase

Accurate staging of prostatic cancer is important for determining treatment. Since the skeletal survey by routine radiography may be negative until approximately 40 percent of bone is involved with tumor, other tests, including marrow acid phosphatase, are used for the detection of early bone metastasis in patients with prostatic cancer. An elevated bone marrow acid phosphatase follows dissemination of prostatic cancer to the marrow space and contraindicates radical surgery in these patients. Normal values for marrow acid phosphatase are the same as for serum acid phosphatase.

Hormonal/Steroid Studies

Certain malignancies are quite apt to change the levels of hormones and/or steroids produced in the body. A study of the hormone/steroid composition of the urine can sometimes be used to infer the presence of such a malignancy.

As medical advances continue to uncover the importance of hormones in a cancer diagnosis, cancer registrars will be required to include a hormone and steroid information in cancer abstracts.

Bilirubin

Bilirubin is a pigment excreted normally by the gallbladder and liver. An elevated bilirubin is indicative of obstruction of the gallbladder or of hepatic disease which affects the function of the liver. Normal values are: One min. 0.4 mg/100 ml. Direct: 0.4 mg/100 ml. Total: 0.7 mg/100 ml. Indirect is total minus direct.

Biomarker

A biological molecule found in blood, other body fluids, or tissues that is a sign of a normal or abnormal process, or of a condition or disease. A biomarker may be used to see how well the body responds to a treatment for a disease or condition. Also called molecular marker and signature molecule.

BUN (Blood Urea Nitrogen)

An elevated BUN may result in uremia reflecting the failure of the kidneys to excrete normal waste materials. For example, it occurs frequently in patients with cancer of the cervix and bladder, where extensive growth of the cancer obstructs the ureters. Normal values are 8-25 mg/100 ml.

Genetic Testing

The process of analyzing cells or tissue to look for changes in genes, chromosomes, or proteins that may be a sign of a disease or condition, such as cancer. These changes may also be a sign that a person has an increased risk of developing a specific disease or condition. Genetic testing may be done on tumor tissue to help diagnose cancer, plan treatment, or find out how well treatment is working.

Uric Acid

In any malignancy with rapid destruction of cells, uric acid may be elevated. It is of particular interest in patients with lymphoma, Hodgkin disease, lymphosarcoma, polycythemia vera, and leukemia treated by radiation therapy and/or chemotherapy. Normal values are 3.0-7.0 mg/ml.

Total Protein

Total protein measures the amount of total circulating protein (albumin and globulin) in the patient's blood serum. It is elevated in multiple myeloma. Low total protein (low level of albumin) is associated with pleural effusion and ascites. Normal values are 6.0-8.0 mg/100 ml.

LDH (Lactic Acid Dehydrogenase)

LDH is an intracellular enzyme which occurs in many body cells. An elevated LDH is indicative of increased cell destruction, possibly from metastatic spread of cancer. Normal values are 60-100µ/ml.

SGOT (Serum Glutamic-Oxalacetic-Transaminase)

SGOT is an enzyme which is specifically manufactured in the liver. It is elevated when the liver does not function normally. Normal values are 10-40100µ/ml.

CEA (Carcino-Embryonic-Antigen)

CEA was first used in 1965 to describe a glyco-protein which is present in extracts of carcinoma cells. An elevated CEA may be indicative of cancer of the gastrointestinal tract and, occasionally, of the breast, lungs, and female reproductive system. When the entire malignancy is removed, the CEA level may drop; it may rise when recurrence or metastasis develops. Normal values are 0-2.5 mg/ml. However, CEA titers less than 2.5 mg/ml are not proof of the absence of malignant disease. Normal values do not apply if the patient is a smoker.

CA 19-9

This test measures the amount of a protein called CA 19-9 (cancer antigen 19-9) in the blood. CA 19-9 is a type of tumor marker. Tumor markers are substances made by cancer cells or by normal cells in response to cancer in the body. High levels of CA 19-9 are often a sign of pancreatic cancer. But sometimes, high levels can indicate other types of cancer or certain noncancerous disorders, including cirrhosis and gallstones. Because high levels of CA 19-9 can mean different things, the test is not used by itself to screen for or diagnose cancer. It can help monitor the progress of your cancer and the effectiveness of cancer treatment. https://medlineplus.gov/lab-tests/ca-19-9-blood-test-pancreatic-cancer/

CA- 125

A substance that may be found in high amounts in the blood of patients with certain types of cancer, including ovarian cancer. CA-125 levels may also help monitor how well cancer treatments are working or if cancer has come back. Also called cancer antigen 125. https://www.cancer.gov/


PSA

Prostate-specific antigen, or PSA, is a protein produced by normal, as well as malignant, cells of the prostate gland. The PSA test measures the level of PSA in a man’s blood. For this test, a blood sample is sent to a laboratory for analysis. The results are usually reported as nanograms of PSA per milliliter (ng/mL) of blood.

The blood level of PSA is often elevated in men with prostate cancer, and the PSA test was originally approved by the FDA in 1986 to monitor the progression of prostate cancer in men who had already been diagnosed with the disease. In 1994, the FDA approved the use of the PSA test in conjunction with a digital rectal exam (DRE) to test asymptomatic men for prostate cancer. Men who report prostate symptoms often undergo PSA testing (along with a DRE) to help doctors determine the nature of the problem. https://www.cancer.gov/


Updated: December 28, 2023