Basic Investigations in Haematology Lecture 4 - Reticulocytes Count Flashcards

75 fill-in-the-blank flashcards covering key facts, definitions, formulas, reference ranges and clinical significance related to reticulocyte counts, indices and staining methods.

The final form of an immature RBC is the __.

polychromatophilic erythrocyte (reticulocyte)

Reticulocytes are slightly __ than mature erythrocytes.

larger

Reticulocytes have __ their nucleus.

extruded (lost)

Reticulocytes contain numerous __, the sites of protein synthesis.

ribosomes

Reticulocytes contain __ that forms a basophilic network.

RNA

On Wright-Giemsa smears, reticulocytes stain a __ color.

blue-purple

Translation of mRNA into protein occurs on the __.

ribosomes

In reticulocytes, haemoglobin is synthesised on the __.

ribosomes

Mature erythrocytes do not contain __ or RNA.

ribosomes

Reticulocytes spend about __ days maturing in the bone marrow.

2–3

After release, reticulocytes need about __ days to mature in peripheral blood.

1–2

Romanowsky-stained polychromatophilic RBCs have a characteristic __ tinge.

blue

Supravital stains precipitate __ inside reticulocytes.

RNA

A bluish coloration of RBCs on smear is termed __.

polychromasia

Polychromasia is often seen in acute blood loss and __ anaemias.

haemolytic

Supravital stains are applied to __ cells.

living

__ and Brilliant Cresyl Blue are common supravital stains for retic counting.

New Methylene Blue

The manual retic count uses an __ solution of supravital stain.

isotonic

To visualise ribosomal RNA, red cells must be stained while they are still __.

living (unfixed)

Reticulocytes are identified by __-blue granules of RNA.

violet

Relative reticulocyte count is expressed as a __ of total red cells.

percentage

The adult reference interval for relative retic count is roughly __ %.

0.2–2.5

At birth, infants normally have __ % reticulocytes.

2–5

Absolute retic count equals relative count multiplied by the __ count.

RBC

The reference range for absolute retic count is __ × 10³/µL.

25–75

In manual counting, reticulocytes are usually counted among __ red cells.

1000

Quality control requires __ the stain before use.

filtering

Preparing blood films in __ helps improve accuracy.

duplicates

Failure to __ the stained blood before making films is a common error.

mix adequately

Mistaking Heinz bodies for reticulin is a source of __ in retic counts.

error

Reticulocyte count is a key, cost-effective test for __ anaemia.

monitoring and classifying

A low retic count in anaemia indicates __ erythropoiesis.

insufficient

The corrected retic percentage for low HCT is called the __ Index.

Reticulocyte

In the RI formula, patient HCT is divided by __ HCT.

normal (reference)

For males, the reference normal HCT used is __ %.

45

For females, the reference normal HCT used is __ %.

42

When demand is high, the marrow releases reticulocytes __ than normal.

earlier

The Reticulocyte Production Index (RPI) corrects for prolonged __ time.

maturation

At an HCT of 25–34 %, the maturation correction factor is __ days.

2.0

A normal RPI in a non-anaemic person is about __.

1

An RPI less than 2 indicates a __ bone marrow response.

hypoproliferative (inadequate)

An RPI greater than 2 suggests a __ bone marrow response.

hyperproliferative (adequate)

Iron deficiency anaemia typically shows an RPI __ 2.

less than

Haemolytic anaemia usually shows an RPI __ 2.

greater than

The “gold standard” indicator of erythropoiesis is the __ retic count.

absolute

For an HCT of 15–24 %, the RPI correction factor is __ days.

2.5

Stress or shift reticulocytes take __ to mature in bloodstream than usual.

longer

The Immature Reticulocyte Fraction (IRF) is based on cellular __ content.

RNA

IRF equals the sum of the __ and HFR fractions.

MFR

High-fluorescence reticulocytes contain a __ amount of RNA.

high

Low-fluorescence reticulocytes have __ RNA content.

low

The CLSI recommends using __ in place of RPI when possible.

IRF

A rising IRF after marrow transplant indicates successful __.

engraftment

IRF rises before a detectable increase in the total __ count.

reticulocyte

IRF is useful for monitoring response to __ therapy in anaemia.

EPO (erythropoietin)

In females, the upper reference limit for IRF is about __ %.

15.9

In males, the lower reference limit for IRF is about __ %.

1.5

Automated retic counts are commonly performed by __ cytometry.

flow

In absolute retic calculations, the RBC count is expressed in ×10⁶ per __.

µL

Absolute retic counts are reported in ×10³ per __.

µL

An RPI of ≥ 2 represents an __ marrow response to anaemia.

adequate

When reticulocytes are scarce, count __ RBCs instead of 500.

1000

The supravital stain concentration used is typically __ % w/v.

1

During staining at 35–37 °C, incubation lasts __ minutes.

10–15

The absolute retic reference range in scientific notation is __ × 10⁶/µL.

0.025–0.075

Polychromasia is a sign of a __ functioning bone marrow.

normally

New Methylene Blue is classified as a __ stain.

supravital

Counting 47 reticulocytes among 1000 RBCs corresponds to __ % retics.

4.7

The anaemia-evaluation algorithm combines absolute retic count with __.

MCV

A high MCV with low retic count may indicate __ deficiency anaemia.

vitamin B12

A low MCV with low retic count commonly indicates __ deficiency.

iron

A normocytic anaemia with low retic count may be due to __ anaemia.

aplastic

Supravital staining allows reticulocyte RNA to be seen because cells have not been __.

fixed

Some textbooks list the adult retic reference interval as 0.5–__ %.

1.5

In the manual method, films should be protected from __ until counted.

dust and insects