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Test ID RTIC Reticulocytes, Blood

Reporting Name

Reticulocytes, B

Useful For

Assessing erythropoietic bone marrow activity in anemia and other hematologic conditions

Specimen Type

Whole Blood EDTA

Necessary Information

Specimen must arrive within 48 hours of draw.

Specimen Required

Container/Tube: Lavender top (EDTA)

Specimen Volume: 3 mL

Specimen Minimum Volume

1.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole Blood EDTA Refrigerated (preferred) 48 hours
  Ambient  24 hours

Reference Values


1-3 days: 3.47-5.40%

4 days-4 weeks: 1.06-2.37%

5 weeks-7 weeks: 2.12-3.47%

8 weeks-5 months: 1.55-2.70%

6 months-23 months: 0.99-1.82%

24 months-5 years: 0.82-1.45%

6-11 years: 0.98-1.94%

12-17 years: 0.90-1.49%

Adults: 0.60-2.71%



1-3 days: 147.5-216.4 x 10(9)/L

4 days-4 weeks: 51.3-110.4 x 10(9)/L

5 weeks-7 weeks: 51.8-77.9 x 10(9)/L

8 weeks-5 months: 48.2-88.2 x 10(9)/L

6 months-23 months: 43.5-111.1 x 10(9)/L

24 months-5 years: 36.4-68.0 x 10(9)/L

6-11 years: 42.4-70.2 x 10(9)/L

12-17 years: 41.6-65.1 x 10(9)/L

Adults: 30.4-110.9 x 10(9)/L

Day(s) Performed

Monday through Sunday

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
RTIC Reticulocytes, B 50262-5


Result ID Test Result Name Result LOINC Value
PRTIC Reticulocytes, B 17849-1
ARTIC Absolute Reticulocyte 60474-4

Clinical Information

Reticulocytes are immature erythrocytes (RBC) that have been released into the peripheral blood from the bone marrow after extrusion of their nucleus. The reticulocyte contains residual polyribosomes used in the formation of hemoglobin in the developing erythrocyte.


The reticulocyte count is a measure of the number of RBCs delivered by the bone marrow. It is elevated with active erythropoiesis such as regeneration, and is decreased in hypoplastic or deficiency conditions such as vitamin B12 deficiency.


Reticulocyte counts must be carefully correlated with other clinical and laboratory findings.


Clotted specimens yield unreliable results and are unacceptable for analysis.

Clinical Reference

1. Adeli K, Raizman J, Chen Y, et al: Complex biological profile of hematologic markers across pediatric, adult, and geriatric ages: establishment of robust pediatric and adult reference intervals on the basis of the Canadian Health Measures Survey. Clin Chem 2015 Aug;61(8):1075-1086

2. CLSI. Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory; Approved Guideline, Third Edition. CLSI document EP28-A3c. Wayne, PA, Clinical and Laboratory Standards Institute, 2008

3. Soldin J, Brugnara C, Wong EC: Pediatric Reference Intervals. Fifth edition. AACC Press. Washington DC 2005. ISBN 1-594250-32-4

4. Clinical Hematology: Principles, procedures, correlations. Second edition. Edited by CA Lotspeich-Steininger, EA Stiene-Martin, JA Koepke. Philadelphia, Lippincott-Raven, 1998, pp 114-117

Method Description

The Sysmex XN 9000 reticulocyte analyzer is a flow cytometer that uses an argon laser as the light source. Whole blood specimens are stained with polymethine fluorescent dye and passed through the laser beam in a sheath flow cell. Each blood cell causes a forward light scatter that depends on cell size. This measurement permits a separation of the various blood cell types so that only erythrocytes are included in the cell count. Erythrocytes containing the protein reticulin (ie, reticulocytes) are stained by the dye in the laser beam. The right-angle fluorescence is measured to count these stained cells. The instrument counts 30,000 erythrocytes in each specimen. Because a known aliquot is counted, an actual RBC per unit volume is performed and an absolute reticulocyte count is obtained.(Instruction manual: Automated Hematology Analyzer XN series [XN-9000], North American edition, Code No. CJ410539. November 2015)

Report Available

1 day

Reject Due To

Gross hemolysis Reject
Other Clotted

Method Name

Flow Cytometry


If not ordering electronically, complete, print, and send a Benign Hematology Test Request Form (T755) with the specimen.