Sickle Cell and ESR laboratory methods.ppt

An ESR test can help measure inflammation in your body. Doctors may use it, along with other tests, to diagnose an inflammatory condition or to monitor an existing condition like arthritis.An ESR test can help measure inflammation in your body. Doctors may use it, along with other tests, to diagnose an inflammatory condition or to monitor an existing condition like arthritis.If your doctor suspects high levels of inflammation in the body, they may recommend a blood test called an erythrocyte sedimentation rate (ESR) test. It looks at how quickly red blood cells may sink to the bottom of a test tube, with a high rate of settlement indicating high inflammation.

Also called a sedimentation rate test or sed rate test, an ESR test doesn’t diagnose one specific condition. Instead, it helps your doctor determine whether you’re experiencing inflammation and what further testing may be needed. The ESR test can also be used to monitor inflammatory diseases you already have.

Learn more about the ESR test, what the results could mean, and what information you may wish to discuss with your doctor before getting your blood drawn.How does the ESR blood test work?
An ESR test measures the rate at which your red blood cells (RBCs) fall to the bottom of a test tube. The blood sample for this test is measured over the course of an hour.

When you’re experiencing inflammation, it can affect your RBCs in a number of ways. First, your RBCs cling together, forming clumps. This clumping affects the rate at which RBCs sink inside a tube where a blood sample is placed.

Also, if you have an acute infection or chronic inflammation, there may be more proteins in your RBCs. This can cause them to settle quicker. The faster and further the cells sink toward the bottom of a test tube, the more likely it is that inflammation is present.

In all, your ESR number is based on the rate that your RBCs settle. The faster this happens, the higher your ESR — and the more inflammation is likely in your body.

When do doctors request an ESR blood test?
An ESR test can identify and measure inflammation, in general, in your body. However, it doesn’t help pinpoint the precise cause of inflammation. That’s why the ESR test is rarely performed alone. Instead, your doctor will likely combine it with other tests to determine the cause of your symptoms.

Also, if you already have an inflammatory condition, your doctor may order an ESR test as part of your routine lab work to make sure your current treatment plan is working.

Diagnosing conditions that cause inflammation
The ESR test can be used to help your doctor diagnose conditions that cause inflammation, such as:

temporal arteritis
autoimmune diseases
cancers
infections
Monitoring inflammatory conditions
The ESR test can help a healthcare professional monitor autoimmune inflammatory conditions, such as:

rheumatoid arthritis (RA)
systemic lupus erythematosus (SLE)
Your doctor might also order this test if you have:

some types of arthrit

1. Sickle CellSickle Cell
1

2. Genetics ReviewGenetics Review

ChromosomesChromosomes

GenesGenes

LociLoci

GenotypeGenotype
2

3. Normal Adult Hemoglobin (Hgb A)Normal Adult Hemoglobin (Hgb A)

Heme molecule composed of iron in the Heme molecule composed of iron in the
ferrous state (Feferrous state (Fe
++++
))

Globin is the protein portionGlobin is the protein portion

95-98% of adult Hgb is Hgb A95-98% of adult Hgb is Hgb A
Remaining amount is ARemaining amount is A
2 2 and Aand A
33
3

4. Sickle Cell Hemoglobin (Hgb S)Sickle Cell Hemoglobin (Hgb S)

The amino acid glutamic acid is replaced by The amino acid glutamic acid is replaced by
amino acid valineamino acid valine

Ability of RBCs oxygen carrying capability Ability of RBCs oxygen carrying capability
is impairedis impaired

Two possible genotypeTwo possible genotype
–AS (sickle cell trait)AS (sickle cell trait)
–SS (sickle cell disease)SS (sickle cell disease)
4

5. Pathophysiology of Sickle CellPathophysiology of Sickle Cell

Sickle Cell traitSickle Cell trait
–Clinical manifestationClinical manifestation

Sickle Cell diseaseSickle Cell disease
–Clinical manifestationClinical manifestation
5

6. Peripheral Blood PicturePeripheral Blood Picture

Varying number of sickled formsVarying number of sickled forms

Marked anisocytosis, poikilocytosis, Marked anisocytosis, poikilocytosis,
and polychromasiaand polychromasia

Target cells, nucleated RBCs, Target cells, nucleated RBCs,
increased WBCs and plateletsincreased WBCs and platelets

Reticulocyte count is elevated: Reticulocyte count is elevated:
(5-25%)(5-25%)
6

7. Sodium metabisulfiteSodium metabisulfite

PrinciplePrinciple
–Cells containing Hgb S will “sickle” Cells containing Hgb S will “sickle”
when placed under a condition of when placed under a condition of
reduced oxygen tensionreduced oxygen tension
Sodium
Metabisulfate
15 minutes
&
30 minutes
7

8. Dithionite tube testDithionite tube test

PrinciplePrinciple
–Hgb S is insoluble in a phosphate bufferHgb S is insoluble in a phosphate buffer
»Results in turbidityResults in turbidity
–Hgb A is solubleHgb A is soluble
»Results in clear appearanceResults in clear appearance
–Other abnormal hemoglobins Other abnormal hemoglobins
may result in turbiditymay result in turbidity
8

9. ESR Clinical SignificanceESR Clinical Significance
• The ESR is a The ESR is a nonspecificnonspecific test that test that
suggests the possibility of an inflammatory suggests the possibility of an inflammatory

process or tissue damage in the bodyprocess or tissue damage in the body
• The ESR is The ESR is not diagnostic not diagnostic but is useful in but is useful in
following the course of some diseases like following the course of some diseases like
rheumatic fever, arthritis, and Lupusrheumatic fever, arthritis, and Lupus

10. PrinciplePrinciple

Based on principle of Based on principle of
sedimentation where solids settle sedimentation where solids settle
to the bottom of a liquidto the bottom of a liquid

A known quantity of A known quantity of
anticoagulated blood is left anticoagulated blood is left
undisturbed, the RBCs separate undisturbed, the RBCs separate
from the plasma and fall to the from the plasma and fall to the
bottom of the containerbottom of the container

11. ProcedureProcedure

Anticoagulated blood is placed in a calibrated tube Anticoagulated blood is placed in a calibrated tube
of standard dimensionsof standard dimensions

It is incubated in a vertical position and left It is incubated in a vertical position and left
undisturbed for a designated period of time undisturbed for a designated period of time
(usually 1 hr)(usually 1 hr)

Distance RBCs fall within the given time is Distance RBCs fall within the given time is
measured in millimeters and reportedmeasured in millimeters and reported
mm/hrmm/hr

12. Types of ESR MethodsTypes of ESR Methods

Wintrobe – simplest and Wintrobe – simplest and
mostcost effectivemostcost effective

Westergren – more sensitiveWestergren – more sensitive

Automated methodsAutomated methods

13. Factors affecting ESRFactors affecting ESR
Plasma factorsPlasma factors
Abnormal plasma proteinsAbnormal plasma proteins
may lead to rouleauxmay lead to rouleaux
formation formation
(falsely increases ESR)(falsely increases ESR)
The single most importantThe single most important
factor in determiningfactor in determining
ESR rateESR rate

14. RBC FactorsRBC Factors

SizeSize
–Large erythrocytes settle faster than Large erythrocytes settle faster than
smaller ones and will increase ESRsmaller ones and will increase ESR

ShapeShape
–spherocytes settle rapidly while sickle cells spherocytes settle rapidly while sickle cells
settle very slowlysettle very slowly

Number of RBCsNumber of RBCs
–In anemia there are less RBCs and more In anemia there are less RBCs and more
plasma volume which increases ESRplasma volume which increases ESR

15. Technical FactorsTechnical Factors

TiltingTilting

Noise and vibrationNoise and vibration

TemperatureTemperature

Test set up within 2hrs of blood collectionTest set up within 2hrs of blood collection

ESR tubeESR tube

Well mixed sampleWell mixed sample

Air bubblesAir bubbles

Accurately timedAccurately timed