Test ID: AF
Chromosome Analysis, Amniotic Fluid
Specimen Type 
Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Provide a reason for referral and gestational age with each specimen, and verify the specimen source. The laboratory will not reject testing if this information is not provided, but appropriate testing and interpretation may be compromised or delayed.
Portions of the specimen may be used for other tests such as measuring markers for neural tube defects (eg, AFPA/9950 Alpha-Fetoprotein, Amniotic Fluid), molecular genetic testing, biochemical testing, and FISH testing (including PAD/81424 Prenatal Aneuploidy Detection, FISH). If additional molecular genetic or biochemical genetic testing is needed, order AFC/80334 Amniotic Fluid Culture for Genetic Testing so that amniocyte cultures may be set up specifically for the use in these tests.
Forms:
1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (Supply T576) is available in Special Instructions.
3. If not ordering electronically, submit a Cytogenetics/AFP Congenital Disorders Request Form (Supply T238) with the specimen.
Advise Express Mail or equivalent if not on courier service.
Specimen Type: Amniotic fluid
Submission Container/Tube: Centrifuge tube
Specimen Volume: 20-25 mL
Collection Instructions:
1. Optimal timing for specimen collection is during 14 to 18 weeks of gestation, but specimens collected at other weeks of gestation are also accepted.
2. Discard the first 2 mL of amniotic fluid.
Additional Information:
1. Place the tube in a Styrofoam container (Supply T329). Fill remaining space with packing material.
2. Unavoidably, about 1% to 2% of mailed-in specimens are not viable. If the specimen does not grow in culture, you will be notified within 7 days of receipt.
3. Bloody specimens are undesirable.
Specimen Type: Fetal body fluid
Container/Tube: Sterile tube
Specimen Volume: Entire specimen
Additional Information:
1. Place the tube in a Styrofoam container (Supply T329). Fill remaining space with packing material.
2. If the specimen does not grow in culture, you will be notified within 7 days of receipt.
3. Clearly indicate on tube and paperwork that specimen is fetal body fluid.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Amniotic Fld | Refrigerated (preferred) | |
| Ambient | ||
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