110.5

What does erythrocyte sedimentation rate (ESR) measure?

degree of settling of RBCs in plasma in an anticoagulated specimen during a specific time

What are some technical sources of error for the ESR?

-Tilting the ESR tube
-Using wrong tube for measurement
-Increased rouleaux formation
-Room temperature increased or decreased
-Air bubbles in the column
-Test not timed for exactly one hour

What are some specimen factors that will affect the ESR?

-Clotted
-Over two hours old

List the normal Westergren ESR for males and females?

Males: 0-15 mm/hr
Males over 50 yo: 0-20 mm/hr
Females: 0-20 mm/hr
Females over 50 yo: 0-30 mm/hr

State the principle of the automated ESR.

Uses capillary photometric-kinetic technology. Small volume of undiluted EDTA-anticoagulates blood is delivered into a capillary tube where it is accelerated via a stopped-flow circuit, which causes sedimentation of erythrocytes. Results are transformed to Westergren values.

What is a supravital stain?

a stain which stains cells in the living state

What stain is used for reticulocytes?

Methylene blue

Where are reticulocytes found after centrifugation of whole blood?

with RBCs?

What is the principle of the manual Reticulocyte Count?

Supravital stains (new methylene blue) are used to demonstrate reticulum in reticulocytes. Residual RNA is precipitated within the reticulocytes. A blood smear is prepared from the mixture of anticoagulated whole blood and supravital stain. The smear is read microscopically
using oil immersion lens fitted with a field restricted ocular (Miller disk), if available

What other RBC inclusions are seen on a reticulocyte smear?

residual RNA

What is the reference range for reticulocytes in an adult when performed by the manual method?

0.5-2.0%

How do reticulocytes stain on a Wright stain?

polychromasia

What is the significance of a high reticulocyte count?

-rapid blood loss
-high elevation
-hemolytic anemias
-medications
-pregnancy

What is the corrected reticulocyte count?

Corrected reticulocyte counts are calculated to account for degree of anemia

A 45 year old male with a hematocrit of 36% has a reticulocyte count of 5%. What is the corrected reticulocyte count?

4%

What is the reticulocyte production index (RPI)?

an index to see if the bone marrow is producing enough RBCs in response to an anemia in a patient

A patient with a hematocrit of 35% has a corrected reticulocyte count of 5%. The maturation time correction factor for a hematocrit of 35% is 1.5. What is the patient's RPI?

3.3%

What is the most rapid, accurate, and precise method for reticulocyte counts?

automated

Uncorrected retic count formula

(# of retics)/(100 RBCs) x 100
or
# of retics/10

Corrected retic count formula

Males: (Pt hct %)/(45%) x Retics%

Females: (Pt hct%)/(42%) x Retics%

Absolute retic count formula

Retic % x RBC (x 10^6/μL) x 10

RPI formula

corrected retic count/RMT

What is an Acute phase Reactants

¨They are non-specific indicators of inflammation (i.e., cannot diagnose a specific infectious agent or process)

¨Serum glycoproteins

What is an example of an Acute phase reactants

¨C-reactive protein, complement, fibrinogen, haptoglobin,alpha-1-glycoprotein, ceruloplasmin, alpha-1-antitrypsin

What are two non-specific test for measuring and monitoring inflammation in the body

Erythrocyte Sedimentation Rate and C-Reactive Protein Test

What is the difference between ESR and C-reactive Protein test

CRP will return to normal, within a day or so, if the focus of inflammation is eliminated.

The ESR will remain elevated for several days until excess fibrinogen is removed from the serum

Which department perform CRP

Chemistry or Immunology Dept of Laboratory

What department perform ESR

Hematology Department of Laboratory

What factors affect ESR

1.Size and number of RBCs

2.Number of RBCs-in anemia

Increasing levels of plasma proteins    

What factors falsely elevated the sed rate

Tilting the tube

Increasing the length of the tube

 Temperature above room temp

                    

What factors falsely decreased the sed rate

     1. Decreased diameter of sedimentation

              tube

        2.  Using old blood collected longer than 2

              hrs, if stored at room temp (this causes

              poikilocytosis, which prevents rouleaux).

          3. Temperature decrease below 20ºC

          4. Incorrect anticoagulant to blood ratio

          5. Air bubbles

        6. Partially clotted samples (uses up      fibrinogen).  Clotted samples should not be set     up.

What are the three stages in ESR test

Lag phase, Decantation phase, Packing phase

Lag phase

first 10 minutes, initial period of aggregation, rouleaux is formed

Decantation phase

period of fast settling, usually lasts about 40 minutes

Packing phase

final period, RBCs crowd closely together, last 10 minutes

What conditions are associated with increase ESR

¨Arthritis, tuberculosis, hepatitis, heart disease, and tissue damage, Waldenstrom’s macroglobulinemia, lupus erythematosus, mutiple myeloma

menstruation, pregnancy, septicemia, and the use of oral contraceptives

What conditions are associated with normal to decreased ESR

Polycythemia, sickle cell anemia and spherocytosis (all produce an increased number of cells), can’t readily form rouleaux

What kind of errors are in Westergren Modified Method

Tilting the ESR tube

Using the wrong tube for measurement

Increased rouleaux formation

Room temperature increased or decreased (should be between 22-24ºC)

Air bubbles in the column

Use of clotted specimen

Blood must be used within 2 hours of collection

Test must be timed for exactly 1 hour

What is an Reticulocyte

Reticulocyte-an immature RBC which contains RNA can be seen when stained with supravital stain

Supravital stain

a stain which stains cells in the living state

Polychromasia

term used to describe the immature RBC(first RBC which lacks a nucleus) when stained with Wright’s stain

What are the different methods to test ESR

Wintrobe (Old-Standard method)

Westergren (modified)

Automated