AF-AFP w/ Reflex to AChE AF-AFP w/ Reflex to AChE

Synonyms

AFP-Amniotic Fluid

Allscripts (AEHR) Order Name

AF-AFP w/ Reflex to AChE

Sunrise Clinical Manager (SCM) Order Name

AFP Amniotic Fluid w/ Reflex to AChE

EPIC Order Name

Alpha Fetoprotein (AFP), Amniotic Fluid with Reflex to AChE

Clinical Info

Measurement of mid-trimester amniotic AFP fluid for detection of open neural tube defects and ventral wall defects.
Samples with AFP values >= 2.0 MoM will reflex to detection of acetylcholinesterase and fetal hemoglobin. 

Specimen Type

Other

Specimen Volume

3 mL Amniotic Fluid (2 mL min)

Container

Screw Cap

Collection Instructions

 Specimen:  3 mL Amniotic Fluid ( 2mL min)
Patient Preparation: 
Patient must be between 15w0d and 21w6d at the time of amniocentesis. Optimally, the patient is between 15w0d and 18w6d. Avoid contamination of amniotic fluid with maternal or fetal blood. No other special preparation is required.
 
Specimen Rejection Criteria: 
       Incorrect tube type
       Insufficient volume
       Fetal/Maternal blood  contamination
      Out of gestational age range
Special Instructions:
The following Ask on Order Entry (AOE) patient information must be provided:  
             Estimated Date of Delivery (EDD)

Transport Instructions

Room Temperature
Refrigerated form overnight Delivery

Specimen Stability

7 days Room Temperature
30 Days Refrigerated

Methodology

Time-Resolved Amplified Cryptate Emission (TRACE)
 
This test was developed, and its performance characteristics determined by Northwell Health Laboratories. 
It has not been cleared or approved by the Food and Drug Administration. The methods and performance 
characteristics have been reviewed and approved by the New York State Department of Health.

Days Performed

Monday - Friday
TAT: 1 -2 Days upon receipt

Performing Laboratory

Northwell Core Lab at CFAM

CPT

82106

PDM

235466

Result Interpretation

For ONTD screening an amniotic fluid alpha-fetoprotein (AFP) multiple of the median (MoM) <2.0 is reported as screen negative. MSAFP MoM >2.0 are reported as screen positive.

AFP Cutoff: 2.0 MoM

Interpretation: 

A screen negative result (<2.0 MoM) indicates low risk for ONTD’s but does not guarantee the absence of neural tube defects (NTD).

A screen-positive result (>2.0 MoM) indicates an increased risk for ONTD’s and triggers reflex testing for amniotic fluid acetlycholinesterase. A combined AFP/AChE report will be provided.

Clinical References:

1. Amniotic-fluid alpha-fetoprotein measurement in antenatal diagnosis of anencephaly and open spina bifida in early pregnancy. Second report of the U.K. Collaborative Study on Alpha-fetoprotein in Relation to Neural-tube Defects. Lancet. 1979 Sep 29;2(8144):651-62

2. Wald N, Cuckle H and Nanchahal K. Amniotic fluid acetylcholinesterase measurement in the prenatal diagnosis of open neural tube defects: Second Report of the Collaborative Acetylcholinesterase study. Prenat Diag 1989 Dec; 9(12) 813-829. 

3. Bradley LA, Palomaki GE, McDowell GA. Technical standards and guidelines: prenatal screening for open neural tube defects. ONTD Working Group, ACMG Laboratory Quality Assurance Committee. Genet Med 2005; 7:355–69.

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