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Test Code RETB Reticulocyte Profile, Blood


Specimen Required


Container/Tube: Lavender top (EDTA)

Specimen Volume: 3 mL

Collection Instructions: Send whole blood specimen in original tube. Do not aliquot.


Useful For

Assessing erythropoietic bone marrow activity in anemia and other hematologic conditions

 

Assessment of acute iron deficiency

 

Monitoring early response to iron therapy or erythropoiesis-stimulating agents

 

Early monitoring of therapy for nutritional anemias (eg, megaloblastic, iron deficiency) where immature reticulocyte fraction precedes reticulocyte count increase by several days

 

Monitoring therapeutic efficacy of erythropoietin treatment

 

Monitoring early engraftment after bone marrow transplantation

Method Name

Flow Cytometry

Reporting Name

Reticulocyte Profile, B

Specimen Type

Whole Blood EDTA

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

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

Reference Values

% RETICULOCYTES

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%

 

ABSOLUTE RETICULOCYTES

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

 

IMMATURE RETICULOCYTE FRACTION (IRF)

1-3 days: 30.5-35.1%

4 days-4 weeks: 14.5-24.6%

5 weeks-2 months: 19.1-28.9%

3-5 months: 13.4-23.3%

6 months-<2 years: 11.4-25.8%

2-<6 years: 8.4-21.7%

6-<12 years: 8.9-24.1%

12-<18 years: 9.0-18.7%

Female-≥ 18 years: 3.0-15.9%

Male- ≥ 18 years: 2.3-13.4%

 

RETICULOCYTE HEMOGLOBIN

Males:

1 day-5 months: 27.6-38.7 pg

6 months-<2 years: 28.7-35.7 pg

2-<6 years: 27.7-37.8 pg

6-<12 years: 32.4-37.6 pg

12-<18 years: 30.0-37.6 pg

Adults: 30.0-37.6 pg

 

Females:

1 day-5 months: 29.2-37.5 pg

6 months-<2 years: 30.1-35.7 pg

2-<6 years: 29.3-37.3 pg

6-<12 years: 30.4-39.7 pg

12-<18 years: 30.0-37.6 pg

Adults: 30.0-37.6 pg

 

RED BLOOD CELL COUNT (RBC)

Males:

0-14 days: 4.10-5.55 x 10(12)/L

15 days-4 weeks: 3.16-4.63 x 10(12)/L

5 weeks-7 weeks: 3.02-4.22 x 10(12)/L

8 weeks-5 months: 3.43-4.80 x 10(12)/L

6 months-23 months: 4.03-5.07 x 10(12)/L

24 months-35 months: 3.89-4.97 x 10(12)/L

3-5 years: 4.00-5.10 x 10(12)/L

6-10 years: 4.10-5.20 x 10(12)/L

11-14 years: 4.20-5.30 x 10(12)/L

15-17 years: 4.30-5.70 x 10(12)/L

Adults: 4.35-5.65 x 10(12)/L

 

Females:

0-14 days: 4.12-5.74 x 10(12)/L

15 days-4 weeks: 3.32-4.80 x 10(12)/L

5 weeks-7 weeks: 2.93-3.87 x 10(12)/L

8 weeks-5 months: 3.45-4.75 x 10(12)/L

6 months-23 months: 3.97-5.01 x 10(12)/L

24 months-35 months: 3.84-4.92 x 10(12)/L

3-5 years: 4.00-5.10 x 10(12)/L

6-10 years: 4.10-5.20 x 10(12)/L

11-14 years: 4.10-5.10 x 10(12)/L

15-17 years: 3.80-5.00 x 10(12)/L

Adults: 3.92-5.13 x 10(12)/L

Clinical Reference

1. Chabot-Richards DS, Zhang QY, George TI. Automated hematology. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics; 6th ed. 2018:1734-1734

2. Ogawa C, Tsuchiya K, Maeda Kl. Reticulocyte hemoglobin content. Clinica Chimica Acta. 2020;504:138-145

3. Parodi E, Romano F, Ramenghi U. How we use reticulocyte parameters in workup and management of pediatric hematologic diseases. Front Pediatr. 2020;8:588617

4. Morton SU, Yuen JC, Feldman HA, et al. Screening with reticulocyte hemoglobin increased iron sufficiency among NICU patients. Pediatr Qual Saf. 2020;5(2):e258. doi:10.1097/pq9.0000000000000258

5. Buttarello M. Laboratory diagnosis of anemia: are the old and new red cell parameters useful in classification and treatment, how? Int Jn Lab Hematol. 2016;38 Suppl 1:123-132

6. Saboor M. Discrimination of iron deficiency, alpha and beta thalassemia on the basis of red cell distribution width and reticulocyte indices. Clin Lab. 2021;67(6):10.7754

7. Morkis IV, Farias M, Scotti L. Determination of reference ranges for immature platelet and reticulocyte fractions and reticulocyte hemoglobin equivalent. Rev Bras Hematol Hemoter. 2016;3 8(4):310-313

8. Soldin J, Brugnara C, Wong EC. Pediatric Reference Intervals. 5th ed. AACC Press; 2005

Day(s) Performed

Monday through Sunday

Report Available

Same day/1 day

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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

85046

LOINC Code Information

Test ID Test Order Name Order LOINC Value
RETB Reticulocyte Profile, B 50262-5

 

Result ID Test Result Name Result LOINC Value
PRTIC Reticulocytes, B 17849-1
ARTIC Absolute Reticulocyte 60474-4
IRF1 Immature Retic Fraction 33516-6
RETHB Reticulocyte Hemoglobin 71694-4
RBC Erythrocytes 789-8

Forms

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

Interpretation

Reticulocyte Quantitation:

The reticulocyte count is a measure of the number of red blood cells 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 Hemoglobin:

Decreased values are suggestive of acute iron deficiency.

Increasing values following treatment with iron or erythropoiesis-stimulating agents suggest early response to therapy.

 

Immature Reticulocyte Fraction:

Immature reticulocyte fraction (IRF) is interpreted in conjunction with the reticulocyte count. It provides similar information as the traditional reticulocyte production index, which was a value calculated from the reticulocyte percentage and hematocrit.

 

An increase in both total reticulocytes and IRF is associated with erythropoiesis in conditions, such as acquired hemolytic anemias, or the loss of blood.(5)

 

A decrease in both IRF and absolute reticulocyte count is associated with reduced marrow production.(5)

 

An increased IRF associated with reduced or normal reticulocyte count is associated with acute infections, myelodysplastic syndromes, or dyserythropoietic anemias.(5)