Cystic fibrosis carrier detection

This test detects mutations in the cystic fibrosis transmembrane regulator (CFTR) gene. This genetic test is used to help screen for cystic fibrosis. A sample of blood, buccal cells, or chorionic villus may be collected for 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. You may need this test if you have:

• Cystic fibrosis screening

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.

Buccal cells:

There is no preparation needed for this test.

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.

A sample of venous blood, buccal cells, or chorionic villus may be collected for this test.

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.

Buccal cells:

Buccal cells are cells from the inner lining of the cheek or mouth. To collect a sample of buccal cells, you will need to open your mouth wide. A special brush or swab will be rotated rapidly up and down on your inner cheeks for 30 seconds. Do not close your mouth when the sample is being collected. After the sample has been collected, the brush or swab will be taken out and tested.

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.

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.

Buccal cells:

This test usually causes no discomfort.

Venous blood:

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

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.

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.

Buccal cells:

There are no special instructions to follow after this test.

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.

You have the right to help plan your care. To help with this plan, you must learn about your health condition and how it may be treated. You can then discuss treatment options with your caregivers. Work with them to decide what care may be used to treat you. You always have the right to refuse treatment.