Lab Evaluation of RBC Hema-Lec

Quality Assurance

A system concerned with monitoring the quality of the entire laboratory performance, including the pre-analytical, analytical, and post-analytical phases.

Pre-Analytical Phase

The phase of laboratory testing that includes factors such as patient identification, specimen collection technique, specimen transport, and monitoring of specimen condition.

Analytical Phase

The phase of laboratory testing that includes factors related to the analysis, such as laboratory personnel competence, assay and instrument selection, assay validation, and internal quality control.

Post-Analytical Phase

The phase of laboratory testing that includes factors after testing, such as accuracy in transcription and filling of results, laboratory report, reference interval and therapeutic range, and turnaround time.

Complete Blood Count

A blood test that provides detailed information about the cells in the blood, including red blood cells, white blood cells, platelets, and red blood cell indices.

Counting Chamber

Also known as a hemacytometer, it is used for manual blood cell counting and consists of counting areas and squares for accurate cell counting.

Red Blood Cell Count

The total number of red blood cells per liter of whole blood, which is an important parameter in assessing various conditions and diseases.

Limitations of Manual Counting

Challenges and limitations associated with manual blood cell counting, including the need for experience, non-uniform distribution of cells, subjectivity, and imprecision.

Decreased RBC Count

Factors that can lead to a decrease in red blood cell count, such as blood loss, bone marrow failure, deficiencies in iron, folate, or vitamins, and certain diseases.

Increased RBC Count

Factors that can lead to an increase in red blood cell count, such as dehydration, high altitude, certain cancers, and conditions like polycythemia vera.

RBC Diluting Fluid

Fluid used to dilute red blood cells for laboratory evaluation, should be isotonic, have a high specific gravity, easy to prepare, a good preservative, have a buffering action, and should not initiate the growth of molds.

Dacie's Fluid / Formol citrate

Best RBC diluting fluid.

NSS

Used in case of excessive rouleaux formation and autoagglutination.

3.8% sodium citrate

A type of RBC diluting fluid.

Hayem's

A type of RBC diluting fluid.

Gower's

A type of RBC diluting fluid.

Toisson's

A type of RBC diluting fluid.

Bethel's Manual RBC Count Procedure

Procedure for counting red blood cells in the laboratory.

Dilution Factor

The factor by which the RBC count is diluted.

Depth

The depth of the counting chamber used for RBC counting.

Area

The area of the squares in the counting chamber used for RBC counting.

General Formula

Formula for calculating RBC count.

Hemoglobin Determination

Screening test for anemia and detection of RBC breakdown.

Hemoglobin

Protein in red blood cells that carries oxygen from the lungs to the tissues and takes carbon dioxide.

Cyanmethemoglobin Method

Reference method for hemoglobin determination.

Drabkin's Reagent

Reagent used in the cyanmethemoglobin method.

Absorbance

The amount of light absorbed by a substance.

Sources of Error

Factors that can affect the accuracy of hemoglobin determination, such as light sensitivity and presence of certain substances in the specimen.

Azide Methemoglobin

Alternative method for hemoglobin determination that avoids dilution and interference from turbidity.

SLS - methemoglobin

Alternative method for hemoglobin determination that avoids the use of toxic materials.

Sahli's Acid Hematin Method

A method used to determine hemoglobin levels in blood samples by adding N/10 HCl and blood sample to an acid solution, allowing it to stand, and then matching the color of the solution to a brown glass standard.

Copper Sulfate Method

Also known as the Specific Gravity Method, it is used to screen blood donors by determining if a drop of blood sinks or floats in a solution of copper sulfate, indicating the hemoglobin level.

Gasometric Method

Also known as the Oxygen Capacity Method, it is commonly used in research laboratories to measure the amount of oxygen that can be carried by hemoglobin. The blood is hemolyzed and the gas is collected and measured in a Van Slyke Apparatus.

Fetal Hemoglobin (HbF) Determination

Tests used to determine the levels of fetal hemoglobin in the blood.

Alkali Denaturation Test

A test that determines if hemoglobin resists alkali denaturation, with HbF resisting while HbA does not.

Acid Elution Test

A test that determines if hemoglobin resists acid elution, with HbF appearing as isolated darkly staining cells among a background of pale staining ghost cells.

Hemoglobin S (HbS) Determination:

Sodium Metabisulfite Test

A test that deoxygenates hemoglobin causing polymerization of RBC, forming sickle cells.

Dithionite Tube Test

A test that converts Fe2+ in hemoglobin resulting in deoxygenation of hemoglobin, with normal hemoglobin being soluble and HbS being insoluble.

Hemoglobin Electrophoresis:

Alkaline Hemoglobin Electrophoresis

A method that separates hemoglobin molecules based on their negative charge at alkaline pH using cellulose acetate as the medium.

Hematocrit Determination

A method used to determine the volume of packed red blood cells (RBC) that occupies a given volume of whole blood.

Macrohematocrit Method

A method that uses a Wintrobe Tube to measure hematocrit levels in whole blood.

Microhematocrit Method

A method that uses a capillary tube to measure hematocrit levels in blood collected from dermal puncture or pre-collected EDTA blood.

Sources of Error

Factors that can lead to false increases or decreases in laboratory evaluation of RBC.

Insufficient centrifugation

Not spinning the sample for long enough, leading to inaccurate results.

Inclusion of buffy coat

Including the layer of white blood cells in the sample, which can affect RBC measurements.

Hemoconcentration

Increased concentration of RBCs due to dehydration or other factors.

Dehydration

Lack of proper hydration, leading to increased RBC concentration.

Macrocytic anemia

A type of anemia characterized by larger than normal RBCs.

Hypochromic anemia

A type of anemia characterized by RBCs with reduced hemoglobin content.

Sickle-cell anemia

A genetic disorder that causes abnormal, crescent-shaped RBCs.

Trapped plasma in the packed RBC layer

Plasma that is not properly separated from the RBCs during centrifugation.

Improper sealing of capillary tubes

Inadequate closure of the tubes used for blood sample analysis.

Increased concentration of anticoagulant

Excessive amount of anticoagulant in the blood sample, affecting RBC measurements.

Prolonged centrifugation

Spinning the sample for too long, leading to inaccurate results.

Acute blood loss

Sudden and significant loss of blood.

Hemolysis

Breakdown of RBCs, leading to the release of hemoglobin into the sample.

Inclusion of interstitial fluid

Fluid found between cells that can contaminate the RBC sample.

Rule of Three

A formula used to validate test results of Hemoglobin and Hematocrit.

Normochromic

RBCs with normal hemoglobin concentration.

Mean Cell/Corpuscular Volume (MCV)

Average size or volume of an individual RBC.

Mean Cell/Corpuscular Hemoglobin (MCH)

Average weight of hemoglobin in an individual RBC.

Mean Cell/Corpuscular Hemoglobin Concentration (MCHC)

Average concentration of hemoglobin in each individual RBC.

Red Blood Cell Distribution Width (RDW)

Coefficient of variation of RBC volume, indicating anisocytosis.

Normocytic

80-100 fL

Mean Cell Hemoglobin (MCH)

Average weight of hemoglobin in an individual RBC.

Normochromic

32 - 36 g/dL

RDW-CW

11.5 - 14.5%

Anisocytosis

Increased wide curve

Microcytosis

shift to the right

Macrocytosis

shift to the right