Amniocentesis
(AFT)

Sample type:

Withdraw a small amount of amniotic fluid from the sac surrounding the fetus.

Uses:

An amniocentesis test can detect chromosomal, genetic disorders or congenital disabilities (sometimes called birth defects) such as:

• Down syndrome.

• Taya-Sachs disease.

• Neural tube defects such as spina bifida or anencephaly.

This test can also evaluate:

• Your baby’s lung development

• Rh disease

Precautions:

• Depending on the stage of your pregnancy.

• In early pregnancy, a full bladder helps move the uterus into a better position for the test.

• In later pregnancy, an empty bladder helps make sure the uterus is well positioned for testing.

• You’ll lie on your back on an exam table.

• Your provider may apply a numbing medicine to your abdomen.

• Your provider will move an ultrasound device over your abdomen.

Interference factor:

• Fetal blood contamination can cause falsely elevated AFP levels.

• Hemolysis of the specimen can alter results.

Pre-analytical errors:

Use of non-sterile equipment.

Corrective of action:

You should reject it and request for another sample.

post analytical errors:

Delay in sending the result.

The corrective action:

Send the result as soon as possible.

Reference range:

The amniocentesis indications were: advanced maternal age (≥35 years) in 75 (40 %), high risk in triple screening test 51 (27 %), advanced maternal age and high risk in triple screening test 11 (6 %), high risk in first trimester screening test 11 (6 %), multiple fetal anomalies detected by obstetric ultrasonography in 14 (7 %), anxiety in cases 5 (3 %) and other indications in 22 cases (12 %). Abnormal karyotypes were detected in 11 of 189 cases (6 %): two trisomy 13 (1 %), two trisomy 18 (1 %), one Turner syndrome (1 %), three trisomy 21 (2 %), and three structural chromosomal anomalies (2 %). There was no pregnancy losses and maternal complication.