Medical Laboratory Science- Clinical Hematology

 HEMOTOLOGY DEPARTMENT  

INTRODUCTION TO CLINICAL HEMOTOLOGY

Hematology involves the study of the blood, in particular how blood can affect overall health or disease. Hematology tests include tests on the blood, blood proteins and blood-producing organs. These tests can evaluate a variety of blood conditions including infection, anemia, inflammation, hemophilia, blood-clotting disorders, leukemia and the body’s response to chemotherapy treatments. Tests may be routine and regular, or they may be called upon to diagnose serious conditions in urgent situations. In many cases, the results of a blood test can give an accurate assessment of body conditions and how internal or external influences may affect a patient’s health.

TASKS ASSIGNED

·        Arrange the worksheets in the order of the reference number and the type of the test

·        To perform tests along with their quality control samples.

·        Perform staining procedures

TYPES OF TESTS PERFORMED IN THE HEMAOROLOGY SECTION

 

1. 1.      Full blood count (CBC)

A full blood count (FBC) is a very common clinical procedure.  FBC, as the name suggests, is used to obtain a count of the blood cells in the sample of blood taken. The counts from this small sample are used to estimate the levels of different blood cells within your body’s blood system. It measures for the following blood components;

• ·        Hemoglobin
• ·        Hematocrit
• ·        Mean Cell Volume
• ·        White blood cell count
• ·        Basophils
• ·        Neutrophils
• ·        Lymphocytes
• ·        Monocytes
• ·        Eosinophil’s
• ·        Platelet count

Test procedure

1.         A blood sample is taken which is prevented from clotting by using a preservative in the blood bottle.

2.        The sample is then put in to the machine which automatically ;

·        Counts the number of red cells, white cells and platelets per milliliter of blood

·        Measures the size of the red blood cells and calculates their average size.

·        Calculate the proportion of blood made up from red blood cells.

·        Measures the amount of hemoglobin in the red blood cells.

 

3.        

  

A blood smear is drawn from the blood sample in order to look for abnormal shapes of cells which cannot be detected by the automated machine.

 

 

 

 

 

 

 

                             Figure:  Blood film for search result in abnormal result

INTRODUCTION

Complete blood count is a test including various parameters describing blood cell morphologies & component of blood for the purpose of Identifying abnormalities information & destruction of blood cells and changes in number of cells and amount of hemoglobin present for diagnosis of hematological disorders. Complete blood count include following parameters.

Hemoglobin (HGB)

Red Blood Cell count (RBC)

Packed Cell Volume (PCV)

Mean Cell Volume (MCV)

Mean Corpuscular Hemoglobin (MCH)

Mean Corpuscular Hemoglobin Concentration (MCHC)

Platelet Count

Red cell Distribution Width (RDW)

White Blood Cell count (WBC)

Differential Count (DC)

·        Neutrophils

·        Lymphocytes

·        Eosinophil

·        Monocytes

·        Basophils

 

PRINCIPLE

The hematology analyzer used in this laboratory based on the aperture impedance principle in which blood cells which are non-conductor of electricity are diluted in a buffered Electrolyte solution and allowed to pass through the orifice of an aperture tube between two electrodes. Interruption of the current by the non-conducting cells alters the electric charge and a pulse is produced. The amplitude of each pulse is proportional to the volume of the cell and the cell count is determined from the total number of pulses obtained from a measured volume of blood.

 

SPECIMEN TYPE, COLLECTION AND STORAGE - EDTA blood sample

 

EQUIPMENT - SYSMEX XS 500i Hematology Analyzer

PROCEDURE

• ·        Check the samples for micro and fibrin clots using glass tubes.
• ·        If micro and fibrin clots are present reject the specimen and record in the specimen rejection registers 
• ·        Cross c b heck the specimen identification data in the container label with those in the work sheet.
• ·        Select Manual Mode icon on the Controller Menu.
• ·        On the IPU, click (Manual) or press (F2)

Procedure for with barcode:

• Read the barcode of specimen

Procedure for without barcode:

• ·        Enter the specimen number (alpha or numeric characters) using the keyboard not being
• ·        Click on CBC or CBC+Diff, if this information provided by the Host Computer.
• ·        Click [OK]
• ·        Mix the patient sample 10 times by end-to-end inversion
• ·        Remove the cap of sample containers. Place the sample under the probe.
• ·        Press Start switch (Located above the sample tube position on the Main Unit of the
• ·        XS-500/ without Sampler; inside the sampler cover on the XS-5001 with Sampler.
• ·        When Ready LED is lit green, repeat steps 1-10 for each additional sample.
• ·        The result will be checked and if the machine indicates a flagged result, the manual check-up will be done.

                                  Figure:  Sysmex XS 500i Hematology Analyzer in Laboratory

                                                        Figure: Loading sample to the machine

 CALCULATIONS

MCV = PCV x 10 / RBC in millions

 

MCH = Hb / RBC in millions X 10

 

MCHC = Hb / PCV X 100

       

 

 QUALITY CONTROL

CBC-X quality control Level 1, Level 2 and Level 3 are run at every morning and plot on LJ charts.

In addition, a selected sample will be run two times (8.00am and 2.00pm respectively) a day and the difference of two values is plotted in a graph.

Participate BIO RAD EQAS programmer.

Analysis Parameters

• The XS-1000/XS-500/provides results for the following parameters
• WBC - Number of all leukocytes
• RBC - Number of all erythrocytes
• HGB- Hemoglobin concentration
• HCT -Hematocrit value: Erythrocyte ratio of total blood
• MCV- Mean erythrocyte volume in total
• MCH -Mean hemoglobin volume per RBC
• MCHC- Mean hemoglobin concentration of erythroches
• PLT- Number of all platelets
• NEUT% - Neutrophil Percent
• LYMPH% -Lymphocyte Percent
• MONO% - Monocyte Percent
• E0% -Eosinophil Percent
• BASO%- Basophil Percent
• NEUT# - Neutrophil Count
• LYMPH# -Lymphocyte Count
• MONO#- Monocyte Count
• EO#- Eosinophil Count
• BASO#- Basophil Count
• RDW-SD -Calculated distribution width of erythrocytes, standard deviation
• RDW-CV -Calculated distribution width of erythrocytes, coefficient variation
• PDW- Calculated distribution width of platelets
• MPV - Mean platelet volume
• P-LCR - Platelet-Large Cell Ratio
• PCT- Plateletcrit

1. 2.Erythrocyte Sedimentation Rate ( ESR)

INTRODUCTION

The most common and traditional laboratory test in the world for detecting acute and chronic inflammatory conditions. Useful in monitoring of response to therapy, especially in rheumatologic diseases and tuberculosis. Although the ESR is a nonspecific test, there is a general impression that markedly elevated ESR may have a greater diagnostic specificity.

The method is easy to perform and inexpensive.

CLINICAL SIGNIFICANCE

• ·        The ESR is an inexpensive, simple test of chronic inflammatory activity.
• ·        The ESR rises with age, but this increase may simply reflect a higher disease prevalence in the elderly,
• ·        The use of the ESR as a screening test in asymptomatic persons is limited by its low sensitivity and specificity.
• ·        In patients with solid tumors, an ESR greater than 100 mm per hour usually indicates metastatic disease.
• ·        An elevated ESR is a key diagnostic criterion for polymyalgia rheumatic and temporal arteritis, but normal values do not preclude these conditions.
• ·        When there is a moderate suspicion of disease, the ESR may have some value as a "sickness index."
• ·        An extremely elevated ESR (>100 mm/hr) will usually have an apparent cause. Most commonly infection, malignancy or temporal arteritis.
• ·        A mild to moderately elevated ESR without obvious etiology should prompt repeat testing after several months rather than an expensive search for occult disease.

 

 PRINCIPLE

• ·       In this laboratory determined ESR by the Westergren method
• ·       Sedimentation of red cells in this system is affected by forces both for and against sedimentation
• ·     The forces resisting sedimentation are the negative charge on the red cell surface(causing red       cells to repel each other (zeta potential)), the up flow of plasma displaced by falling red cells,     and the rigidity of red cells.
• ·      The forces accelerating sedimentation are anemia, and plasma proteins.
• ·       Plasma proteins bind to red cell membranes thereby reducing the zeta potential thus allowing rouleaux formation to occur.
• ·        During the first, or lag phase, the red cells form a characteristic rouleaux pattern and sedimentation is generally slow.
• ·        The rate accelerates in the second period, the Decantation Phase, and slows again in the final Packing Phase as red cell aggregates pile up at the base of the tube.
• ·        The size of the rouleaux aggregates formed
• ·        The size of the rouleaux aggregates formed in the lag phase is the critical factor affecting the final result of the ESR.
• ·        The rouleaux itself appears to be influenced mainly by certain plasma proteins including fibrinogen, IgM and alpha2-macroglobulin.
• ·        Opinions vary as to the accelerating and retarding properties of glycoproteins & albumin

SPECIMEN TYPE, COLLECTION AND STORAGE

·        EDTA ant coagulated blood specimen

·        Ideally test should be performed 2 hrs. of collection of the specimen

·        Delays up to 6 hrs. allowed if blood kept at 4°C

·        ESR is reduced in stored blood

·        Citrated blood can also be used

 

EQUIPMENT

Westergren Tube and ESR rack

 PROCEDURE

• ·        Daily morning before mounting ESR check the vertical and horizontal level of ESR rack and mark it on the result entry sheet.
• ·        Check the identification details on specimen and request form
• ·        Label a glass tube with the laboratory auto generated number
• ·        Measure 50 mm length of citrate solution into dry plastic tube using ESR tube.
• ·        Gently mixed the blood sample and add 200 mm length of blood from ESR tube into the tube containing citrate solution
• ·        Then mix carefully without forming air bubbles.
• ·        The mixture is then aspirated into a vertical Westergren tube, which has a uniform internal diameter, to a height of 200mm.
• ·        Place the tube in ESR rack vertically and note the position number on the request form and also the time which the result has to be read. Adjust one hour and turn on an alarm/stopwatch when the ESR tube is mounted.
• ·        After one hour the distance that the red cells sediment down through the plasma is read by the lowest level of the meniscus
• ·        Results expressed as mm/1 hour

 

REFERENCE VALUES

Children and Adolescents

<17 Yrs.: <10 mm in 1st hour

	17- 50 yrs.	51-60 Yrs.	61-70 Yrs.	> 70 Yrs.
Male	10 mm in 1 hour	12 mm in 1 hour	14 mm in 1st hour	30 mm in 1st hour
Female	12 mm in 1st hour	19 mm in 1st hour	20 mm in 1st hour	35 mm in 1st hour

 

Pregnancy

Early: 48 mm in 1st hour

Late: 70 mm in 1st hour

 

 

                                                                                              Figure: ESR westergren type