EDUCATION
About Pathology and Pathologists
Pathology is a general term for the study of disease. It encompasses the diagnosis of the structural and functional changes in molecules, cells, tissues and organs that underlie disease, illness or dysfunction.
Pathology’s primary goal is to study and understand the four main aspects of disease:
- Etiology: what causes disease
- Pathogenesis: the mechanism by which a certain etiological factor causes disease, or the means by which disease is caused
- Morphologic changes: the structural changes induced in cells, tissues and organs as a result of disease
- Clinical significance: the functional consequences of the morphologic changes taking place in the body
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Pathologists are medical doctors (M.D.) or doctors of osteopathic medicine (D.O.). They are required to complete a four year undergraduate program, four years of medical school training, and four to five years of postgraduate training in the form of a pathology residency. Their training may be within two primary specialties, as recognized by the American Board of Pathology:
- Anatomic Pathology: the science of diagnosing diseases based on the appearance of tissues, both gross and microscopic.
- Clinical Pathology: the science of diagnosing diseases based on the analysis of body fluids like blood and urine.
Following general training, many pathologists continue to train in a more specialized field including General Surgical Pathology, Gastrointestinal Pathology and Genitourinary pathology, Hematopathology, Dermatopathology, Microbiology, and Clinical Chemistry.
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Tools of pathology
Pathologists use a variety of techniques to study disease processes and diagnoses. The ones used most often are:
- Gross pathology: the recognition of disease based on macroscopic examination of surgical specimens generated at the time of surgery or autopsy.
- Histology: the microscopic study of tissues. Histopathology is the science of diagnosing diseases on the basis of the histological aspect of the diseased tissues.
- Blood bank/transfusion medicine: the clinical lab is responsible for processing and distributing donor blood to blood transfusion recipients.
- Clinical chemistry: the gathering, detection and reporting of an incredible array of chemical measures found by the analysis of collected body samples.
- Cytology: the study of detached cells. Cytopathology is the scientific study of disease changes within individual cells or cell types. The most common application of this technique is the Pap smear.
- Flow cytometry : analysis of a process that allows for the identification of specific cells.
- Immunology: the use of specific immune markers and antibodies to aid in the diagnosis of disease.
- Immunohistochemistry: commonly known as IHC, refers to the process of localizing proteins in cells of a tissue section exploiting the principle of antibodies binding specifically to antigens in human tissues. Immunohistochemical staining is widely used in the diagnosis and treatment of cancer. Specific molecular markers are characteristic of particular cancer types.
- Microbiology: deals with the study of microorganisms including bacteria, viruses, fungi and parasites which are of medical importance and are capable of causing diseases in human beings.
- Molecular pathology:. Molecular pathology focuses on the use of nucleic acid based techniques such as DNA sequencing, fluorescent in-situ hybridization, reverse-transcriptase polymerase chain reaction and nucleic acid microarrays for specialized studies of disease in tissues and cells.
- Telepathology: allows consultations between pathologists and other physicians via the Internet and includes the study of images from gross surgical pathology specimens as well as histopathology and cytology specimens.
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What happens when my doctor or surgeon removes some of my body tissue during an office visit or surgery?
Your tissue sample is submitted to a laboratory where it is processed and stained for microscopic examination. The pathologist uses several techniques along with microscopic examination to search for any type of disease before issuing a diagnosis via a pathology report. This pathology report is returned to the requesting doctor or surgeon who is then responsible for discussing its findings with you. Since pathologists most often communicate with other doctors, they are sometimes nicknamed "the doctor's doctor."
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What is a pap smear?
The Papanikolaou test or Papanicolaou test (also called Pap smear, Pap test, cervical smear, or smear test) is a medical screening method primarily designed to detect premalignant and malignant processes in the ectocervix (the portion of the uterine cervix extending into the vagina).
Samples are collected from the outer opening or os of the cervix and placed into a vial containing a liquid medium which preserves the cells. The sample is then sent to the laboratory where it is stained using the Papanicolaou technique, in which dyes and acids are selectively retained by cells to highlight cytoplasmic keratinization.
The sample is then screened by a specially trained and qualified cytotechnologist using a light microscope. The results are reported via a cytology report to the physician that collected the specimen.
The same liquid sample is also suitable for low and high risk HPV testing. The physician collecting the sample typically decides if the patient qualifies for HPV testing in addition to the Pap smear.
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Why do I need lab tests done on my blood, urine or other body fluid?
A laboratory or lab test is a medical procedure in which a sample of blood, urine, or other tissues or substances in the body is checked for certain features. Such tests are used as part of a routine checkup to identify possible changes in a person’s health before any symptoms appear. Lab tests also play an important role in diagnosis when a person has symptoms. In addition, these tests may be used to help plan a patient’s treatment, evaluate response to treatment, or monitor the course of disease over time.
Lab test samples are analyzed to determine whether results fall within normal ranges. They may also be checked for changes occurring since previous tests. Normal test values are usually given as a range, rather than as a specific number, because normal values vary from person to person. What is normal for one person may not be normal for another. Many factors (including sex, age, race, medical history, and general health) can affect test results. Test results can also be affected by specific foods, medications and how closely a patient follows pre-test instructions. That is why a patient may be asked not to eat or drink for several hours before a test. It is also common for normal ranges to vary somewhat from lab to lab.
Some lab tests are precise, reliable indicators of specific health problems. Others provide more general information that simply gives doctors clues to possible health problems. Information obtained from lab tests may help doctors decide whether other tests or procedures are needed to make a diagnosis. The information may also help the doctor develop or revise a patient’s treatment plan. All lab test results must be interpreted in the context of the overall health of the patient and are generally used along with other exams or tests. The doctor who is familiar with the patient’s medical history and current condition is in the best position to explain test results and their implications, thus patients are encouraged to discuss questions or concerns about lab test results with their individual doctor.
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What are send-out or specialized lab tests?
Occasionally, very specialized lab tests need to be performed to complete the patient’s diagnosis. These specialized tests are performed in limited laboratories based on the type of test needed. Typically, blood and tissue specimens are collected at the local hospital or laboratory and sent to the specialized laboratory for testing. The lab test results are then returned to the requesting physician. Examples of specialized lab tests are flow cytometry used to diagnose lymphoma or leukemia and cytogenetic studies performed on bone marrow and blood specimens.
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About your lab tests
Doctors often order lab tests as an aid in diagnosing disease in their patients.
The following blood tests and panels (groupings of tests) are some of the most common:
Complete Blood Count (CBC)
The CBC provides your doctor with vital information about the important cells in your blood. The red blood cells contain hemoglobin and deliver oxygen to your body. The white blood cells are part of your immune system and respond to infection or stress. Platelets are tiny cells which help your blood to clot normally.
Electrolyte Panel
Normal blood contains natural ions which are critical to your health. This panel allows your doctor to see if these ions are properly balanced.
Lipid Panel
This panel measures your triglyceride and cholesterol levels including both "good" cholesterol (HDL) and "bad" cholesterol (LDL). These levels allow your doctor to determine your risk for preventable heart attack and stroke.
Hepatic Function Panel
This series of tests tells your doctor how well your liver is functioning. The liver plays an important roll in nutrition and in removing natural toxins from your blood.
Basic Metabolic Panel
This panel measures your blood sugar (glucose) along with a number of other natural ions and proteins. These allow your doctor to check the function of your kidneys and to test for diabetes.
Comprehensive Metabolic Panel
This group of tests combines both the Hepatic and Metabolic Panels and allows your doctor to assess the health of your liver and kidneys. These vital organs are involved in nutrition, blood purification and in maintaining your body's natural chemical balance.
Prostate-Specific Antigen (PSA)
PSA is normally produced in small amounts by a man's prostate gland. An abnormally high level in the blood can be a sign of prostate cancer.
Thyroid Stimulating Hormone (TSH)
TSH is an important hormone in controlling the function of your thyroid gland. Abnormally high or low levels can be a sign of thyroid disease.
Iron
Your body uses iron to make hemoglobin which allows your blood to deliver oxygen to your body. A low level can lead to anemia and may be a sign of abnormal bleeding.
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Patient Links
College of American Pathology
Anatomic Pathology Patient
Information Sheets
Lab Tests Online: A Wealth of Information for Patients
American Medical Association
http://www.ama-assn.org/
American Society of Clinical Pathologists
http://www.ascp.org/
Note: Brazos Valley Pathology, P.A., does not attest to the validity of information found on the above websites. Please consult your physician with any questions you may have regarding information from these sites.
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