Test ID: AFC
Amniotic Fluid Culture for Genetic Testing
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Producing amniocyte cultures that can be used for genetic analysis
Once confluent flasks are established, the amniocyte cultures are sent to other laboratories, either within Mayo Clinic or to external sites, based on the specific testing requested.
Genetics Test Information Provides information that may help with selection of the correct test or proper submission of the test request
Aminocyte culture for prenatal genetic testing. The additional test(s) desired must be indicated on the request form that accompanies the specimen.
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Method Name A short description of the method used to perform the test
Cell Culture
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Cell culture, Amniotic fluid
Culture for Genetic Testing, Amniotic Fluid
Genetic Testing Culture, Amniotic Fluid
Saving cells for possible genetic testing
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. The laboratory will not reject testing if this information is not provided, but appropriate testing and interpretation may be compromised or delayed.
Optimal timing for specimen collection is during 14 to 18 weeks of gestation, but specimens collected at other weeks of gestation are also accepted.
Container/Tube: Amniotic fluid container
Specimen Volume: 5-10 mL
Collection Instructions:
1. Discard the first 2 mL of amniotic fluid. If the culture will be performed in conjunction with chromosome analysis and alpha-fetoprotein, a total of approximately 25 mL to 30 mL will be needed for the combined studies.
2. Place the tubes in a Styrofoam container (Supply T329).
3. Fill remaining space with packing material.
4. Unavoidably, about 1% to 2% of mailed-in specimens are not viable.
5. Bloody specimens are undesirable.
6. If the specimen does not grow in culture, you will be notified within 7 days of receipt.
Additional Information:
1. Advise Express Mail or equivalent if not on courier service
2. Results will be reported and also telephoned or faxed, if requested.
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.
2. If not ordering electronically, submit a Cytogenetics/AFP Congenital Disorders Request Form (Supply T238) with the specimen.
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 | Ambient (preferred) | |
| Refrigerated | ||
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Fetal cells obtained by amniocentesis (amniocytes) are used for a wide range of laboratory tests. Prior to testing, the cells may need to be cultured to obtain adequate numbers of amniocytes.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Not applicable
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Prior to obtaining amniotic fluid specimens for specific genetic testing, it is crucial to identify a laboratory that will perform testing for the disorder in question and establish that they will perform the study on amniocytes.
Including clinical information provided with the specimen is very useful. This allows the laboratory to identify or verify the correct testing to perform.
Interfering factors:
-Technical
- Improper syringes or transport vessels may damage amniotic cells, see Specimen Required
- Transport time should not exceed 2 days
- A bloody specimen may interfere with attempts to culture cells
- Inadequate amount of fluid (we recommend 25 mL of fluid) may not permit adequate culture for analysis
- Improper packaging may result in broken, leaky, and contaminated specimens
- Exposure of the specimen to temperature extremes (freezing or >30 degrees C)
-Biologic
- It is difficult to differentiate between maternal and fetal cells in some specimens. Culturing of maternal cells rather than fetal cells can cause discrepant results.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Barch MJ, Knutsen T, Spurbeck JL: In The AGT Cytogenetics Laboratory Manual. 3rd edition, 1997
Method Description Describes how the test is performed and provides a method-specific reference
The specimen is split into 8 to 10 separate culture dishes. The cells are grown on coverslips in culture media for 4 to 10 days. The cultures are trypsinized into 2 to 3 T25 tissue culture flasks or 1 to 2 T75 tissue culture flasks. (United States Department of Health, Education and Welfare, Amniotic Fluid Cell Culture: Training Manual. Center for Disease Control, Atlanta, GA, 1980, pp 1-15)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Samples processed Monday through Sunday. Results reported Monday through Friday, 8 a.m.-5 p.m. CST.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
88235-Tissue culture for amniotic fluid
88240-Cryopreservation
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 16179 | Specimen | 31208-2 |
| 16338 | Specimen ID | N/A |
| 16793 | Source | N/A |
| 16180 | Order Date | N/A |
| CG132 | Reason For Referral | 42349-1 |
| 16184 | Method | In Process |
| 16187 | Interpretation | 69965-2 |
| 16188 | Amendment | In Process |
| 16189 | Consultant | N/A |
| 16190 | Report Date | N/A |
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