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Test Code FNUL Phenotyping for Duffy-null associated neutrophil count 

Specimen and Container/Tube

Whole Blood, pink top vacutainer 

Specimen Handling and Transport Instructions

Collect specimen and label tube with handwritten collection time, date (MM/DD/YY or MM/D/YYYY), and phlebotomist's initials. 

Deliver sample directly to Blood Bank (CCD 2-730) or via PTS tube station 400. 

Rejection Criteria

Wrong container type, clotted sample, or improper labeling (needs collection time, date, and initials). 

Fee Code

86905

Specimen Type

EDTA anticoagulated whole blood with hand written collection time, date (MM/DD/YY or MM/DD/YYYY), and initials on sample. 

Specimen Volume

Preferred volume: 3 mL

Pediatric volume: 2 mL

Minimum volume: 1 mL 

Clinical Indications

For evaluation of neutropenia in patients of African or Middle Eastern in identification of the Duffy-null associated neutrophil count (formerly so called "benign ethnic neutropenia").

Additional Information

Test consists of serological typing for Fy(a) and Fy(b) antigens.  Genotyping is not included in this assay. 

Test is invalid if the patient has been transfused in the last 3 months.

Turnaround Time

7 days    *no STAT available*

Day(s) performed: 24/7

Synonyms/Keyword Search

Duffy null

Fy null 

Last Review Date

Last reviewed RM 08/14/2024.