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Health Library : Lab Tests & Results Print [PDF]
Browse by the First Letter(s) of the Lab Test
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Chromosome breakage assay

What is this test?

This test detects certain chromosome abnormalities in cells. It is used to evaluate for genetically-linked diseases, such as Fanconi's anemia.[1][2][3] A sample of venous blood, bone marrow, amniotic fluid, chorionic villus, skin, or another body fluid or tissue may be collected for this test[4].

What are related tests?

  • Flow cytometry

Why do I need this test?

Laboratory tests may be done for many reasons. Tests are performed for routine health screenings or if a disease or toxicity is suspected. Lab tests may be used to determine if a medical condition is improving or worsening. Lab tests may also be used to measure the success or failure of a medication or treatment plan. Lab tests may be ordered for professional or legal reasons. The following is a possible reason why this test may be done:

  • Fanconi's anemia

When and how often should I have this test?

When and how often laboratory tests are done may depend on many factors. The timing of laboratory tests may rely on the results or completion of other tests, procedures, or treatments. Lab tests may be performed immediately in an emergency, or tests may be delayed as a condition is treated or monitored. A test may be suggested or become necessary when certain signs or symptoms appear.

Due to changes in the way your body naturally functions through the course of a day, lab tests may need to be performed at a certain time of day. If you have prepared for a test by changing your food or fluid intake, lab tests may be timed in accordance with those changes. Timing of tests may be based on increased and decreased levels of medications, drugs or other substances in the body.

The age or gender of the person being tested may affect when and how often a lab test is required. Chronic or progressive conditions may need ongoing monitoring through the use of lab tests. Conditions that worsen and improve may also need frequent monitoring. Certain tests may be repeated to obtain a series of results, or tests may need to be repeated to confirm or disprove results. Timing and frequency of lab tests may vary if they are performed for professional or legal reasons.

How should I get ready for the test?

Venous blood:

Before having blood collected, tell the person drawing your blood if you are allergic to latex. Tell the healthcare worker if you have a medical condition or are using a medication or supplement that causes excessive bleeding. Also tell the healthcare worker if you have felt nauseated, lightheaded, or have fainted while having blood drawn in the past.

Bone marrow:

A bone marrow biopsy is a procedure that requires written consent. Review the consent form with the healthcare worker and ask any questions that you have before signing the consent form.

Tell the healthcare worker if you have a medical condition or are using a medication or supplement that causes excessive bleeding. You should also report if you have a history of allergic or other reactions to local anesthetics. Inform the healthcare worker of any past or present bone diseases. You may need to have other tests done before a bone marrow biopsy.

To prepare for a bone marrow biopsy, you may be offered a mild sedative prior to the procedure to help you relax. To decrease pain, you will also receive a topical or local anesthetic injection at the biopsy site.

Amniotic fluid:

An amniocentesis is a procedure that requires your written consent. Review the consent form with the healthcare worker and ask any questions that you have before signing the consent form. Tell the person doing the amniocentesis if you have a history of pregnancy difficulties, such as premature (early) labor, incompetent cervix (a weak or failing cervix), placenta previa (a placenta that is abnormally low, near or over the cervix), abruptio placentae (the placenta is separated from the uterine wall too early), and if you are Rh negative (had a blood type that did not match your child's blood type). Tell the healthcare worker if you have a medical condition or are using a medication or supplement that causes excessive bleeding. You should also report if you have a history of allergic or other reactions to local anesthetics. If ultrasound is used, you will need to drink extra fluids and have a full bladder for the procedure.

Chorionic villus:

CVS is a procedure that requires your written consent. Review the consent form with the healthcare worker and ask any questions that you have before signing the consent form. Tell the person doing the CVS if you have a history of pregnancy difficulties, such as premature (early) labor, incompetent cervix (a weak or failing cervix), placenta previa (a placenta that is abnormally low, near or over the cervix), abruption placentae (the placenta is separate from the uterine wall too early), and if you are Rh negative (Rh incompatibilities happen when a baby’s blood has a protein that the mother does not, thus causing an immune reaction). Tell the healthcare worker if you have a medical condition or are using a medication or supplement that causes excessive bleeding. You should also report if you have a history of allergic or other reactions to local anesthetics. Depending on method used to do the CVS, you may be asked to drink extra fluids and have a full bladder for the procedure.

Skin:

Written consent may be required for a skin biopsy. Review the consent form with the healthcare worker and ask any questions that you have before signing the consent form.

Tell the healthcare worker if you have a medical condition, or are using a medication or supplement that causes excessive bleeding. You should also report if you have a history of allergic or other reactions to local anesthetics.

Other body fluid or tissue samples:

A different sample other than the samples listed above may be used for this test. Ask your healthcare worker for information about how to prepare for this test. If you have questions or concerns about the preparation for this test, talk to the healthcare worker.

How is the test done?

Venous blood:

When a blood sample from a vein is needed, a vein in your arm is usually selected. A tourniquet (large rubber strap) may be secured above the vein. The skin over the vein will be cleaned, and a needle will be inserted. You will be asked to hold very still while your blood is collected. Blood will be collected into one or more tubes, and the tourniquet will be removed. When enough blood has been collected, the healthcare worker will take the needle out.

Bone marrow:

Bone marrow is the tissue inside certain bones where new blood cells are made. A bone marrow sample is collected by biopsy. Local anesthesia may be used for a bone marrow biopsy. Your skin will be shaved and cleaned, and a sterile area will be prepared for the procedure. A needle will be inserted through the skin and into the bone using a twisting motion. A sample of marrow will be removed with a syringe, and another needle will be used to remove a piece of tissue. When the samples are collected, the needle will be removed.

Amniotic fluid:

Amniotic fluid is the protective liquid that surrounds the unborn baby while it is in the mother’s womb. A sample of this fluid is collected by a procedure called an amniocentesis. For an amniocentesis, you will lie on your back with your legs extended. You may be asked to raise your arms above your head. Usually, an ultrasound will be done at the same time as the amniocentesis. The ultrasound is used to locate your unborn baby, the placenta, and a pocket of amniotic fluid that is suitable for testing. The point selected for needle insertion will be away from your baby and the placenta.

An area of skin on your abdomen will be cleaned with an antiseptic solution, and a sterile area prepared. You will be given anesthetic to numb your skin. When the area is numb, a needle will be introduced through your skin and into the amniotic sac (the protective sac that surrounds the unborn baby). Using ultrasound as a guide for needle placement, a small amount of amniotic fluid will be withdrawn and thrown away, and then the sample of fluid will be collected.

When enough fluid has been collected, the needle will be withdrawn. More than one needle and syringe may be needed to collect the sample. If your unborn baby moves toward the needle during the procedure, the needle will be withdrawn and the procedure may need to be repeated.

Chorionic villus:

The chorionic villus is a part of the placenta (the organ that nourishes the baby during pregnancy). A sample of chorionic villus is collected by a procedure called chorionic villus sampling (CVS). Depending on the location of your placenta, CVS may be done either through your cervix (transcervically) or abdomen (transabdominally). Both methods will require you to lie down and will use ultrasound to assist the sample collection. For a transcervical CVS, you will be in a position similar to a Pap smear. A speculum will be used to gently spread apart your vagina. Your cervix or vagina will be cleaned with an antiseptic solution. A flexible catheter will be placed through your cervix and a small sample removed. For the transabdominal method, a needle will be used to go through the abdominal wall into the placenta. This will allow a syringe to draw out a small sample of placenta.

If a transabdominal method is used, you will be asked to lie on your back. An area of skin on your abdomen will be cleaned with an antiseptic solution, and a sterile area prepared. You will be given anesthetic to numb your skin. When the area is numb, a needle will be placed through your skin and into the placenta. A small sample of the placenta will be collected and the needle will be withdrawn. All CVS procedures may need to be repeated to collect a sufficient sample size.

Skin:

Pleural fluid is the fluid in between the membrane linings of your lungs. A procedure called a thoracentesis is done to get a pleural fluid sample for testing. A healthcare worker will first need to locate the fluid that needs to be sampled. This is done by a chest x-ray, ultrasound, or by percussion (rhythmically pounding the chest wall). Once the fluid is located, a healthcare worker may hold up the arm on the same side where the procedure will be done. Your skin will be cleaned with antiseptic, and a local anesthetic is injected to numb the area. A needle will be inserted into the fluid pocket. Fluid samples are then drawn out using a needle attached to a syringe. When a large enough sample is collected, the needle will be removed. A thoracentesis may be done with or without the assistance of ultrasound or CT scan.

Other body fluid or tissue samples:

A different sample other than the samples listed above may be used for this test. Methods used to collect other body fluids or tissue samples may vary. Ask the healthcare worker to explain how this sample may be collected. If you have questions or concerns about this test, talk to the healthcare worker.

How will the test feel?

The amount of discomfort you feel will depend on many factors, including your sensitivity to pain. Communicate how you are feeling with the person doing the test. Inform the person doing the test if you feel that you cannot continue with the test.

Venous blood:

During a blood draw, you may feel mild discomfort at the location where the blood sample is being collected.

Bone marrow:

Before a bone marrow biopsy, you may receive medication to help you relax. When the numbing medicine is injected, you may feel mild discomfort or stinging. The local anesthetic is used to minimize pain, but as the procedure needle is inserted, you may feel some pressure and discomfort. You may feel brief pain as the bone marrow is removed. You may feel discomfort at the procedure site for several days.

Amniotic fluid:

Before an amniocentesis, a local anesthetic is given to the procedure site to numb the area. You may feel mild discomfort or stinging when the numbing medicine is injected. As the procedure needle is inserted through the abdomen, you may feel some discomfort and pressure. You may feel mild cramping in your abdomen and pelvic area during the procedure. The procedure site may be sore for several days.

Chorionic villus:

During a transcervical CVS procedure, you may feel mild cramping in your abdomen or pelvic area. Before a transabdominal or transcervical CVS procedure, a local anesthetic is given to the procedure site to numb the area. You may feel mild discomfort or stinging when the numbing medicine is injected. As the procedure needle or catheter is inserted through the abdomen or cervix, you may feel some discomfort and pressure. You may feel mild cramping in your abdomen and pelvic area during the procedure. The procedure site may be sore for several days.

Skin:

Before the skin biopsy, a local anesthetic is given to the procedure site to numb the area. You may feel mild discomfort or stinging when the numbing medicine is injected. After the medication wears off, the biopsy area may be sore for several days.

Other body fluid or tissue samples:

A different sample other than the samples listed above may be used for this test. This test may feel different depending on many factors, including the sample needed and how it is collected. Ask the healthcare worker what to expect during this test.

What should I do after the test?

Venous blood:

After a blood sample is collected from your vein, a bandage, cotton ball, or gauze may be placed on the area where the needle was inserted. You may be asked to apply pressure to the area. Avoid strenuous exercise immediately after your blood draw. Contact your healthcare worker if you feel pain or see redness, swelling, or discharge from the puncture site.

Bone marrow:

After the sample of bone marrow is collected, pressure may be applied and a bandage will be placed over the biopsy site. You will be given instructions for when to remove the bandage, and the signs and symptoms of infection to watch for. Contact your healthcare worker if you experience a fever or increased pain, and if you see increasing redness, swelling, or pus at the procedure site.

Amniotic fluid:

After an amniocentesis, a bandage will be placed over the site, and pressure applied until the bleeding or drainage has stopped. Rest is necessary. Do not have sexual intercourse, and avoid heavy lifting for at least 24 hours after the procedure.

Contact your healthcare worker if there is redness, swelling, pus, drainage, or pain at the site where the amniotic fluid sample was taken. Alert your healthcare worker immediately if you see bleeding or clear fluid leaking from your vagina, feel severe cramping in your abdominal or pelvic area, or develop a fever. Inform healthcare workers of any change in your baby's movement, such as not moving for a period of time, or suddenly moving more than usual after this procedure.

Chorionic villus:

After all CVS procedures, ultrasound and fetal monitoring may be done immediately after the procedure. If a needle was used, pressure may be held to the site until the bleeding or drainage has stopped. A bandage will be placed over the site if a transabdominal method was used. After all CVS procedures, rest is necessary. Do not have sexual intercourse, douche, and avoid heavy lifting for at least 24 hours after all the procedures.

Contact your healthcare worker if there is redness, swelling, pus, drainage, or pain at the procedure site if the transabdominal method was used. For all procedure methods, alert your healthcare worker immediately should you develop a fever; bleeding (heavier than light spotting), fluid leakage or discharge from your vagina; or severe abdominal cramping or pain. An ultrasound is usually done 2 to 4 days after the CVS to make sure that the fetus is doing well.

Skin:

After a skin biopsy is completed, pressure may be held on the area, and a dressing placed over the biopsy site. If the incision is large or deep, stitches, staples, or adhesive strips may be used to close the biopsy site. Ask for instructions for how to care for the bandage and how to monitor for signs and symptoms of infection. Contact your healthcare worker if you have a fever or increased pain, and if you see redness, swelling, or pus at the procedure site.

Other body fluid or tissue samples:

A different sample other than the samples listed above may be used for this test. Instructions for what to do after a collection of other body fluid or tissue samples may vary. Ask the healthcare worker to instruct you on what to expect after this test is completed. If you have questions or concerns about what to expect after the test is completed, talk to the healthcare worker.

What are the risks?

Ask the healthcare worker to explain the risks of this test or procedure to you before it is performed.

Blood: During a blood draw, a hematoma (blood-filled bump under the skin) or slight bleeding from the puncture site may occur. After a blood draw, a bruise or infection may occur at the puncture site. The person doing this test may need to perform it more than once. Talk to your healthcare worker if you have any concerns about the risks of this test.

Bone marrow: Bone marrow is collected by a procedure called aspiration and biopsy. The sample may be taken from multiple sites, but the most common site for biopsy is the pelvis. Risks of a bone marrow biopsy vary depending on the biopsy method used and the site selected for the biopsy. General risks of this procedure are infection and bleeding from the biopsy site. If you have a medical condition, or are using a medication or supplement that causes excessive bleeding, you are at a higher risk of bleeding from the procedure site.

Bone marrow biopsies performed on the sternum (breastbone) have the most risk. This area is only tested on adults, and only certain types of biopsies are done on the sternum. Due to the location and thickness of the sternum, it is rare but possible to damage the heart, major blood vessels, and the mediastinum (space of the chest that holds essential organs). A puncture to these areas could lead to severe bleeding, infection, or trapped air in the chest cavity. The person doing this procedure may need to perform it more than once. Talk to your healthcare worker if you have any concerns about the risks of having a bone marrow aspiration and biopsy.

Amniotic Fluid: Amniotic fluid is collected by a procedure called an amniocentesis. During an amniocentesis a hematoma (blood-filled bump under the skin) or bleeding at the puncture site may occur. If you have a medical condition, or are using a medication or supplement that causes excessive bleeding, you are at a higher risk of bleeding from the puncture site. It is possible that the needle that is used to collect fluid will injure your baby. After an amniocentesis, a bruise or infection may occur at the puncture site. You may bleed or leak amniotic fluid from the vagina. Rarely, you may develop a fever, have severe abdominal and pelvic cramping, or go into labor. There is a risk that your baby will not survive the procedure. The chances of these risks vary depending on your health status, the reason for having this procedure, and other factors. The person doing this test may need to perform it more than once. Talk with your healthcare worker if you have any concerns about the risks of having an amniocentesis.

Placental tissue (chorionic villus): A placental tissue sample is collected by a procedure called chorionic villus sampling (CVS). Depending on where your placenta is located, different methods may be used. CVS risks, depending on the method, include bleeding and infection at the site. If you have a medical condition, or are using a medication or supplement that causes excessive bleeding, you are at a higher risk of bleeding from the puncture site. It is possible that the needle or catheter that is used to collect the tissue will injure the baby. You may develop a fever, an abnormal vaginal discharge, abdominal pain or cramping, or go into labor. If there is a possibility that you and your baby are not Rh compatible, you may need additional treatment to avoid further complications. There is a risk that your baby will not survive the procedure, or may be adversely affected by this procedure. It is possible that the baby’s limbs, fingers, and toes may be affected by this procedure. The chances of these risks vary depending on your health status, how long you have been pregnant before the CVS procedure, and other factors. The person doing this test may need to perform it more than once. Talk with your healthcare worker if you have any concerns about the risks of having CVS.

Skin tissue: A sample of skin tissue is collected by biopsy. Multiple methods and sites may be used for a biopsy. The risks for this procedure will vary depending on the method and location used to collect the sample. However, bleeding and infection are possible risks when having a skin biopsy. If you have medical condition, or are using a medication or supplement that causes excessive bleeding, you are at a higher risk of bleeding during or after this procedure. The person doing this procedure may need to perform it more than once. Talk to your healthcare worker if you have any concerns about the risks of this test.

Other body fluid or tissue samples: A different sample other than the samples listed above may be used for this test. Ask your healthcare worker to explain the risks of this test to you. If you have questions or concerns about this test, talk to the healthcare worker.

What are normal results for this test?

Laboratory test results may vary depending on your age, gender, health history, the method used for the test, and many other factors. If your results are different from the results suggested below, this may not mean that you have a disease. Contact your healthcare worker if you have any questions. The following is considered to be a normal result for this test:

  • No chromosomal abnormalities detected

What follow up should I do after this test?

Ask your healthcare worker how you will be informed of the test results. You may be asked to call for results, schedule an appointment to discuss results, or notified of results by mail. Follow up care varies depending on many factors related to your test. Sometimes there is no follow up after you have been notified of test results. At other times follow up may be suggested or necessary. Some examples of follow up care include changes to medication or treatment plans, referral to a specialist, more or less frequent monitoring, and additional tests or procedures. Talk with your healthcare worker about any concerns or questions you have regarding follow up care or instructions.

Amniotic fluid:

After an amniocentesis, results are usually available within 7 to 10 days.

Chorionic villus:

After a CVS procedure, it may take from 1 to 4 weeks to receive results. There is a possibility that you may need an amniocentesis if the CVS was not successful.

Skin:

After a skin biopsy, healthcare workers may use stitches or staples to close the wound. A return appointment may be necessary to have the stitches or staples removed. Wound care may also be necessary. Ask your healthcare worker for instructions following the skin biopsy.

Other body fluid or tissue samples:

A different sample other than the samples listed above may be collected for this test. Ask the healthcare worker for follow up care instructions after this test.

Where can I get more information?

Related Companies

References

  1. Garcia-Higuera I, Kuang Y, & D'Andrea AD: The molecular and cellular biology of fanconi anemia. Current Opinion in Hematology 1999; 6(2):83-88.
  2. Alter BP: Bone marrow failure syndromes. Diagnostic pediatric hematology 1999; 19(1):113-133.
  3. D'Andrea AD & Grompe M: Molecular biology of fanconi anemia: implications for diagnosis and therapy. Blood The journal of the American society of hematology 1997; 90(5):1725-1736.
  4. Henry JB: Clinical Diagnosis and Management by Laboratory Methods, 20th ed. Saunders, 2001.

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