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Test Code RETP Reticulocyte Count, Automated or Manual, Blood

Methodology

The Sysmex XN analyzers are an automated, quantitative, multi-parameter hematology analyzer for in vitro diagnostic use, employing hydrodynamic focusing (DC Detection), flow cytometry method (semiconductor laser), impedance, and SLS-hemoglobin methods. 

 

The analyzer, which uses a single aspiration pathway, provides a multi-parameter CBC by counting and sizing red blood cells and platelets using electronic resistance detection (sheath flow DC method). Hematocrit is directly measured as a ratio of the total RBC volume to whole blood (using cumulative pulse height detection), and Hemoglobin is converted to SLS-hemoglobin and read photometrically.

 

The white blood cell count, differential, reticulocyte parameters, fluorescent platelet (PLT-F), and nucleated red blood cells are all evaluated using flow cytometry with a semiconductor laser.  The laser exploits the differences in cell size, complexity, and RNA / DNA content. Forward scattered light provides information on blood cell size while lateral scattered light provides information on the cell interior (such nuclear size). Lateral fluorescent light intensity will increase as the concentration of the stain increases.  Fluorescent light is emitted in all directions and will be detected and measured by the XN.

Performing Laboratory

Munson Healthcare Laboratories

Specimen Requirements

Container/Tube: 3ml Lavender-top (K2EDTA) tube or 500ul (K2EDTA ) microtainer tube

Note: 6mL Lavender-top (K2EDTA) tubes will be rejected.

 

Specimen Volume:  3mL of K2EDTA whole blood minimum 1mL in 3ml K2EDTA tube or 250uL whole blood in K2EDTA microtainer tube

 

Stability/Handling/Transport:

  1. Stored at 4-8oC, EDTA blood samples with normal results may be analyzed up to 48 hours without significant loss of differential stability.  Note:  Munson Medical Center does not refrigerate EDTA blood samples.
  2. Sample stability at room temperature is 24 hours.  Samples stored at room temperature may exhibit an increase in MCV after 24 hours, which may be minimized by refrigeration.
  3. Allow refrigerated samples to come to room temperature and mix well before analysis.

 

Collection Instructions: Forward promptly.  Specimen must arrive within 24 hours of draw.

 

Note: Medicare frequency limitations exist for this test in addition to diagnosis requirements. See Advance Beneficiary Notice of Noncoverage (ABN) form in Special Instructions.

Reference Values

Reference Range:

Pediatric  reference ranges are based on a Boston Children’s Hospital study that was published in Pediatric Reference Intervals, Eighth Edition, copyright 2021, Chapter 2 by Wong, Brugnara, Straseski, Kellogg and Adeli. These were derived using the Sysmex XN testing platform on which our assays are also performed. Updated 2/28/2023

 

TEST Retic %IG
UNIT x109 /µL %
1-3  days Male 140-350 0.4-3.0
Female 150-520 0.4-3.7
4-7 days Male 50-180 0.3-3.6
Female 30-190 0.4-3.3
8-14 days Male 30-140 0.2-1.9
Female 40-280 0.2-2.2
15-30 days Male 20-120 0.2-1.1
Female 20-140 0.1-1.3
31-60 days Male  40-150 0.1-1.2
Female 40-130 0.1-1.2
61-180 days Male   0.1-0.4
Female   0-1.3
0.5-<2 years Male   0-1.7
Female   0-0.7
2-<6 years Male   0-0.7
Female   0-0.8
6-<12 years Male   0-1.1
Female   0-0.9
12-<18 years Male   0-0.8
Female   0-0.8
18-21 years Male   0-1.2
Female   0-0.9
Adult
MHC System		 Male    
Female    

Test Priority & Frequency

STAT, ASAP, Non-Emergent 

24 hours 7 days a week

Test Classification and CPT Coding

85044 - manual

85045 - automated