Haematology - Effects of Disease on Lab Tests

Lab Results for Haematological Disorders

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Iron Deficiency Anaemia	Megaloblastic Anaemias and Vitamin B12 Deficiency	Folic Acid	Anaemia of Chronic Disease
Anaemia of Chronic Renal Insufficiency	Anaemia of Hypometabolism	Hereditary Spherocytosis	Glucose-6-Phosphate
Pyruvate Kinase deficiency	The Thallasemias	Sickle Cell Disease	Haemoglobin C Disease
Autoimmune Haemolytic Anaemia	Drug Induced Immune Haemolysis	Haemolytic-Uraemic Syndrome	Paroxysmal Nocturnal Haematuria
Haemolytic Disease of the Newborn	Aplastic Anaemia	Sideroblastic Anaemia	Anaemia of Marrow Infiltration
Haemophilia A	Von Willebrands Disease	Haemophilia B	Disseminated Intravascular Coagulation
Ideopathetic Thrombocytopenic Purpura	Chronic Granulomatous Disease	Myelofibrosis With Myeloid Metaplasia	Polycythaemia Vera
Essential Thrombocytopenia	Acute Leukaemia	Chronic Myelocytic Leukaemia	Chronic Lymphocytic Leukaemia
Malignant/Non-Hodgkin's Lymphomas	Hodgkins Disease	Immunoproliferative Disorders	Leukaemic Reticuloendotheliosis
Multiple Myelomas	Macroglobulinaemia	Heavy Chain Disease	.

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IRON DEFICIENCY ANAEMIA

LABORATORY FINDINGS

Peripheral Blood

Normal or decreased reticulocytes reflect impaired marrow response to anaemia in absence of iron.

Sequential Stages in the Development of Iron Deficiency

Normal indices, no anaemia, and depleted iron stores, indicated by decreased serum ferritin and marrow haemosiderin - early iron deficiency
Normocytic, normochromic anaemia follows complete depletion of iron stores; variable anisocytosis and poikilocytosis
Microcytic, hypochromic anaemia indicates late iron deficiency.

Bone Marrow

Decreased or absent stainable iron (haemosiderin) is the earliest indicator of iron depletion; it precedes anaemia. Stainable marrow iron indicates storage iron.
Variable cellularity - there is a poor correlation between the severity of anaemia and the degree of erythroid hyperplasia.
Decreased sideroblasts, which are iron-containing normoblasts

Other Laboratory Findings*

Decreased serum ferritin - this is the earliest indicator of iron depletion, usually corresponding to marrow iron stores. This might be normal in the presence of accompanying chronic disease, liver disease, or malignant neoplasm.11
Increased iron binding capacity - this occurs only after storage iron is completely depleted. The iron binding capacity is a measure of serum transferrin.
Decreased serum iron and transferrin saturation (<16% early, <10% late)
Increased free erythrocyte protoporphyrin - this provides the same information as transferrin saturation but is a slower and more stable indicator of iron storage.

Laboratory Findings of Underlying Disease

See diseases and conditions discussed above.

Diagnosis of iron deficiency is usually straightforward
Determining the cause can be difficult

Iron metabolism

The body contains about 5g of iron
70% is found in haemoglobin
Daily dietary requirements are about 1 mg in a man and 3 mg in a women
An average western diet contains about 15 mg of iron daily only 5-10% of which is absorbed
Absorption occurs in the ferrous form in the upper part of small intestine

Iron is carried to bone marrow by plasma transferrin

Iron is stored bound to ferritin and as haemosiderin

About 1 mg of iron is lost per day in urine, faeces and shed cells

Menstrual losses account for an extra 20 mg per month

Clinical features

Depend of rate of onset
If insidious then symptoms are often few
Commonest symptoms are of lethargy and dyspnoea
Skin atrophy occurs in about 30% of patients
Nail changes include koilonychia (spoon shaped nails)
Patients may also develop angular stomatitis and glossitis
Oesophageal and pharyngeal webs may be seen
Examination should be directed to possible underlying cause

Causes of iron deficiency

Increased blood loss - uterine, GI tract, urine
Increased demands - prematurity, growth, child-bearing
Malabsorption - post-gastrectomy, coeliac disease
Poor diet

MEGALOBLASTIC ANAEMIAS AND VITAMIN B12 DEFICIENCY

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LABORATORY FINDINGS

All Megaloblastic Anaemias

Peripheral Blood

Normochromic macrocytic (mean corpuscular volume {MCV} 100 um3 - 150 um3) anaemia (7 g/dl - 8 g/dl) with many oval macrocytes (macroovalocytes)
Moderate to marked poikilocytosis and anisocytosis
Basophillic stippling, Howell-Jully bodies, Cabot's rings
Nucleated RBC when haematocrit is low (<20%); these show typical megaloblastic features
Reticulocytes are usually decreased, indicating ineffective erythropoiesis.
Hypersegmented enlarged neutrophils are often seen before RBC changes - These cells reflect abnormal nuclear division.
Thrombocytopenia; variably sized platelets
Leukopenia

Bone Marrow

Increased cellularity, which is predominantly erythrocytic; this changes the myelocytic - erythrocytic (M-E) ratio from 3 : 1 to 1 : 1
Predominance of promegaloblasts; there are also many other megaloblastic RBC precursors, which reflect impaired DNA metabolism
Enlarged granulocytic bands and metamyelocytes reflect impaired DNA metabolism.
Enlarged megakaryocytes reflect impaired DNA metabolism.
Increased stainable iron

Other Laboratory findings

Increased serum iron reflects ineffective erythropoiesis and decreased RBC formation.
Normal or slightly decreased total iron binding capacity
Markedly increased lactate dehydrogenase (LDH) (predominance of LDH1) reflects ineffective erythropoiesis, marrow destruction of blood-cell precursors, and release of LDH from RBC; the magnitude of the increase is related to the degree of anaemia.
Slight increase in unconjugated bilirubin reflects ineffective erythropoiesis and RBC destruction in the marrow.

Pernicious Anaemia

Decreased serum vitamin B12 - this is the single most important diagnostic test
Increased vitamin B12 binding capacity
Lack of gastric acid, even following stimulation with betazole (Histalog) or pentagastrin; pH of gastric juice > 3.5; this does not decrease by more than 1 pH until after stimulation
Abnormal Schilling test - decreased absorption of radioisotope-labelled vitamin B12 with normalization of absorption when oral intrinsic factor is given. The various intestinal disorders that may lead to vitamin B12 deficiency show no correction of impaired vitamin-B12 absorption following intrinsic-factor administration.
Antibodies to intrinsic factor (56% - 60% of patients) and to parietal cells (84% - 90% of patients).

Megaloblastic Anaemia - Bone Marrow

Megaloblastic Anaemia - Peripheral Blood

FOLIC ACID DEFICIENCY

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LABORATORY FINDINGS

Peripheral Blood

Findings identical to those in vitamin B12 deficiency

Bone Marrow

Findings identical to those in vitamin B12 deficiency

Other Laboratory Findings

Decreased serum folate - this is the most sensitive indicator of folate deficiency, falling within a month of deficient intake (Fig. 8-1). This falls many weeks before megaloblastic anaemia appears. Serum folate levels may change abruptly with changes in diet.
Decreased RBC folate - this appears after 3 months - 4 months of folate deficiency (Fig. 8-1). RBC folate is an index of tissue folate stores.
When folate stores are depleted, megaloblastic anaemia occurs.
Findings of ineffective erythropoiesis - increased serum iron, unconjugated bilirubin, and LDH1
Normal gastric acid; normal Schilling test; normal serum vitamin B12

Laboratory Findings of Impaired Intestinal Absorption or Its Causes

Gluten enteropathy
Lymphoma
Amyloidosis
Scleroderma
Whipple's disease

ANAEMIA OF CHRONIC DISEASE

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LABORATORY FINDINGS

Peripheral Blood

Normochromic, normocytic anaemia (8 g/dl - 12 g/dl; occasionally <7 g/dl); many patients have microcytosis (MCV < 80um3) and hypochromia (mean corpuscular haemoglobin concentration (MCHC) <31 g/dl)
Usually normal reticulocyte count; may occasionally be reduced or slightly increased

Bone Marrow

Normal cellularity and maturation
Increased bone marrow RE iron - reflects impaired marrow utilisation of stored iron. The increase in storage iron in the presence of decreased serum iron and marrow sideroblasts is characteristic of this disorder.
Decreased sideroblasts

Other Laboratory Findings

Decreased serum iron - characteristic finding; precedes anaemia
Decreased transferrin, which is usually measured as total iron binding capacity - occurs after the decrease in serum iron. This contrasts with increased total iron binding capacity in iron deficiency.
Decreased transferrin saturation (mean 15% range 10% - 25%); not as low as in iron deficiency
Normal or increased serum ferritin - because ferritin increases in inflammatory disorders, the level is disproportionately elevated for the amount of marrow iron.11 This contracts with decreased ferritin in iron deficiency.

Laboratory Findings of Underlying Disease

See diseases discussed above.

ANAEMIA OF CHRONIC RENAL INSUFFICIENCY

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LABORATORY FINDINGS

Peripheral Blood

Normochromic, normocytic anaemia (haemoglobin 5 g/dl - 10 g/dl) - characteristic finding
Microcytic anaemia occurs when there is iron deficiency due to bleeding seconary to various platelet dysfunctions. It may also be due to iron loss in haemodialysis fluid.
Macrocytic anaemia - due to loss of folate in haemodialysis fluid
Occasional burr or helmet cells
Acanthocytes and schistocytes, especially in haemolytic-uremic syndrome
Usually normal reticulocyte count; might be slightly decreaed; a moderate increase in reticulocytes may occur with higher blood urea nitrogen (BUN) levels.

Bone Marrow

Normal bone marrow appearance; might appear somewhat hypoplastic

Other Laboratory Findings

Usually normal serum iron, total iron binding capacity, transferring saturation; these may all be decreased if iron deficiency occurs.
Laboratory findings of chronic renal insufficiency

ANAEMIA OF HYPOMETABOLISM

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LABORATORY FINDINGS

Normocytic, normochromic anaemia (>10 g/dl) - characteristic of hypothyroidism
Microcytic, hypochromic anaemia is a consequence of uterine bleeding in hypothyroidism
Laboratory findings of anterior pituitary insufficiency, hypothyroidism, Addison's disease, or seconary testicular failure

HEREDITARY SPHEROCYTOSIS

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LABORATORY FINDINGS

Peripheral Blood

Increased spherocytes with decreased cell diameter (microspherocytes)
Normocytic, or slightly microcytic, hyperchromic (MCHC 36 g/dl - 40 g/dl) anaemia (haemoglobin {Hb} 9 g/dl - 12 g/dl) - the increased MCHC reflects cell membrane loss
Increased reticulocytes (5% - 20%) - reflects marrow response to RBC destruction
Macrocytes and polychromatophilia reflect reticulocytosis.
Increased RBC distribution width and anisocytosis reflect two RBC populations.

Bone Marrow

Normoblastic hyperplasia
Hypoplasia may occur in the presence of an aplastic crisis.
Megaloblasts may occur with complicating folate deficiency, which may supervene in any severe chronic haemolytic anaemia. This is the result of accelerated folic acid utilisation and DNA synthesis in response to normoblastic hyperplasia.
Moderate haemosiderin deposits

Other Laboratory Findings

Indicators of extravascular haemolysis - increased LDH (especially LDH1 and LDH2)1 unconjugated (indirect) bilirubin, urine haemosiderin; decreased or absent serum haptoglobin.
Negative Coomb s' test

Increased Osmotic Fragility Test

Spherocytes in peripheral blood

Splenomegaly in Hereditary Spherocytosis

GLUCOSE-6-PHOSPHATE DEHYDROGENASE DEFICIENCY
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LABORATORY FINDINGS

Diagnostic Laboatory Tests

No Haematologic Findings in the Absence of haemolysis

Haematologic Findings in the Prescence of Haemolysis

Phase 1

Acute haemolysis (1 day - 3 days after oxidative drug exposure)
Normocytic, normochromic anaemia - rapid occurrence, severe indicators of haemolysis - increased LDH, unconjugated bilirubin, reticulocytes; decreased haptoglobin
Increased Heinz bodies (characteristic feature), basophillic stippling, polychromatophilia
Fragmented RBC and spherocytes, if haemolysis is severe
Marrow shows normoblastic hyperplasia.

Phase 2

Recovery (5 days - 15 days after oxidative drug exposure)
Reticulocytosis (8% - 12%)
Macrocytes reflect reticulocytosis.
Increase in Hb and haematocrit over earlier values
Absent haptoglobin reflects chronic haemolysis.

Phase 3

Resistance (more than 7 days - 10 days after oxidative drug exposure)
Haemolysis stops and anaemia disappears.
Young cells produced in response to haemolysis have nearly normal levels of enzyme and are relatively resistance to haemolysis. This phase continues as long as the same dose of the drug is administered.

PYRUVATE KINASE DEFICIENCY

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Definition
Pyruvate kinase deficiency is an inherited deficiency in the red blood cell of the enzyme pyruvate kinase. The deficiency is responsible for a form of hemolytic anemia

Causes and risks
Pyruvate kinase deficiency is transmitted as an autosomal recessive trait. There are many different types of enzymatic defects of the red blood cell that produce hemolytic anemia. However, pyruvate kinase deficiency is important because it is the second most common cause (G-6-PD, glucose-6-phosphatase dehydrogenase is number one) of enzymatic-related hemolytic anemia.
Pyruvate kinase deficiency may produce mild or severe hemolysis and anemia. Problems may first appear in the newborn as prolonged neonatal jaundice and anemia. Older children may be pale (from their anemia) and have intermittent episodes of jaundice. Occasionally it is not discovered until adulthood in mild cases.

LABORATORY FINDINGS

Peripheral Blood

Normochromic, normocytic anaemia (haematocrit 18% - 36%)
Slight macrocytosis reflects reticulocytosis.
Increased reticulocytes, up to 2.5% - 15% with haemolysis and up to 56% following splenectomy
Polychromatophilia, poikilocytosis, anisocytosis, irregularly contracted or crenated RBC, occasional nucleated RBC
No spherocytes
No Heinz bodies

Bone Marrow

Normoblastic hyperplasia

Other Laboratory Findings

Positive fluorescence screening test
Decreased RBC pyruvate kinase (5% - 25% of normal). This is the only specifically diagnostic test.
Vatiably positive autohemolysis test- the abnormality is not corrected by the addition of glucose,because these cells cannot metabolize glucose.
Findings of hemolysis-increases LDH, unconjugated bilirubin ; decreased or absent serum haptoglobin.
Normal osmotic fragility test.

Pyruvate kinase deficiency an autosomal recessive disorder causing polychromasia, anisocytosis, poikilocytosis with burr cells and acanthocytes, and NRBCs.
Reduced ATP formation causes RBC membrane rigidity, resulting in hemolysis. Symptoms are usually mild as increased 2,3-DPG causes a right shift of the 02-dissociation curve.
Persons homozygote for PK deficiency show severe anemia and are usually discovered in childhood.
Splenomegaly, cholelithiasis and jaundice are frequent.

THE THALASSEMIAS

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Definition
Hereditary disorders characterized by defective production of hemoglobin, which leads to anemia.

Causes and risks
An imbalance in the alpha and beta protein globin chains necessary for the production of hemoglobin is caused by the inheritance of a defective gene. There are two types, alpha thalassemia and beta thalassemia. Genes must be inherited from both parents to acquire the disease. If one gene is inherited, the person will be a carrier of the disease but will not have symptoms. Alpha thalassemias occurs in people from southeast Asia and China, and are caused by deletion of a gene or genes from the globin chain. The most severe form of alpha thalassemia causes a stillborn fetus as a result of hydrops fetalis.
Beta thalassemia occurs in people of Mediterranean origin, and to a lesser extent, Chinese, other Asians, and blacks. It is caused by a mutation in the globin chain. Affected children are normal at birth but develop anemia during the first year of life. Growth failure, bone deformities, and enlarged liver and spleen are some of the problems that can occur. Blood transfusions may modify some of the disease manifestation, but iron overload from the transfusions can cause damage to the heart, liver, and endocrine systems. A milder form of the disease, thalassemia minor, produces iron-deficient appearing blood cells, with no symptoms. Risk factors include a family history of thalassemia and an ethnic background susceptible to the disease. The incidence varies widely throughout the world.

LABORATORY FINDINGS

Beta-thalassemia Minor

Peripheral Blood

Target cells, polychromatophilia, basophilic stippling, occasional nucleated RBC, anisocytosis, poikilocytosis
Slight hypochromic (MCH 20 pg-22pg), microcytic (MCV 50 um3 - 70 um3) anaemia (haemoglobin 9 g/dl - 11 g/dl), with normal to increased RBC (>5.7 million/ul)
Increased reticulocytes (2% - 10%)

Bone Marrow

Slight normoblastic hyperplasia; abundant iron deposits

Other Laboratory Findings

Electrophoresis shows increased HbA2 (3.5% - 8%); increased HbF (1% - 5%) in 50% of patients; increased HbA2 is diagnostic
Decreased osmotic fragility; this has been used as a rapid screening test
Normal to increased serum iron; normal serum ferritin

Image 1A

Image 1b

Image 1c

Thalassemia Image Series(Link to Image source)BLOODLINE
Image 1A - Beta thalassemia minor (200 X Magnification)
28-year-old female with a life-long history of anemia. Her mother and several great-aunts have a similar history. Laboratory values include 11.0 hgb/33 hct and 66 MCV.
Most of the red cells are smaller than the lymphocyte's nucleus, so appear microcytic. Most are normochromic but a few appear hypochromic. A few elliptocytes and target cells are noted.
Image 1B - Beta thalassemia minor (400 X Magnification)
Same woman as image 1a. Note the numerous poikilocytic red cells (elliptocytes, keratocytes or bite cells, schistocytes, target cells and spherocytes) which are usually present in this hemoglobinopathy.
Image 1C - Beta thalassemia minor (400 X Magnification)
Same woman as image 1a. A few oval and elliptocytes are present. One cell containing coarse basophilic stippling is at right of center.

Beta-thalassemia Major

Peripheral Blood

Marked anisocytosis, poikilocytosis, target cells (10% - 35%), spherocytes, fragmented RBC; occasional nucleated RBC, basophilic stippling, siderocytes; inclusion bodies representing aggregated alpha chains
Marked hypochromic, microcytic anaemia (Hb 2.5 g/dl - 6.5 g/dl)
Increased reticulocytes (4% - 10%) - this increase is lower than that which normally occurs with severe anaemia and indicates inadequate marrow response
Increased white blood cell (WBC) count (10,000/ul - 25,000/ul) with occasional immature granulocytes
Occasional thrombocytopenia - reflects effect of secondary hypersplenism

Bone Marrow

Marked normoblastic hyperplasia with poor haemoglobinisation; basophilic stippling; abundant iron deposits; RBC cytoplasmic inclusions, which are free alpha chains; clinical severity correlates with amount of alpha-chain precipitation

Other Laboratory Findings

Electrophoresis shows HbF 10% - 100% decreased or absent HbA; HbA2 1% - 8%
Decreased osmotic fragility
Findings of haemolysis - increased unconjugated bilirubin, increased LDH, decreased haptoglobin
Increased serum iron and transferrin saturation
Decreased serum folate - reflects increased marrow utilisation of folate

Thalassemia Image Series(Link to Image source)BLOODLINE

6-month-old baby girl with a Greek ancestry. She has been pale and listless with frequent episodes of irritability throughout her young life. Relevant laboratory values are 6.7 hgb/20 hct, 62 MCV, 11.5 uncorrected retic and 10 nucleated red cells per 100 identifiable white cells.

A late erythroblast appears in the upper left quadrant. It is smaller than normal and displays scanty cytoplasm which is defective in hemoglobin color. Some red cells are large and slightly gray-blue (polychromatophilic). They represent red cells newly reIeased from the marrow in response to the anemia. The majority of the red cells are microcytic. Many are hypochromic. The many poikilocytes (ovalocytes, elliptocytes, tear drops, schistocytes) represent red cells which have been traumatized, deformed and/or split when negotiating small passages in the spleen. They contained precipitated hemoglobin chains, known as Heinz bodies, which were too large to squeeze through these tiny passages and were removed from the red cells in transit.

Alpha-thalassemia Minor

Mild hypochromic microcytic anaemia
Peripheral blood - rare HbH inclusions in RBC after brilliant cresyl blue incubation.
Electrophoresis - newborn, Bart's Hb (2% - 10%); adult, normal Hb electrophoresis

HbH Disease

Severe haemolytic anaemia (Hb 7 g/dl - 10 g/dl)
Peripheral blood - hypochromic microcytes, target cells, irregularly crenated RBC; many HbH inclusions in RBC, especially following splenectomy
Increased reticulocytes (5% - 10%)
Electrophoresis - newborn, increased Bart's Hb (20% - 40%), which is gradually replaced during the first months of life by HbH; adult, HbA 70% - 95%; HbH 5% - 30%; trace of Bart's Hb

Haemoglobin H (Link to image source)

The blood film shows hypchromia, microcytosis, and target cells. HbH disease is due to deletion of three out of four alpha globin genes, resulting in an anaemia which varies from mild to severe.

SICKLE-CELL DISEASE

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Sickle cell disease is an inherited blood disorder in which there is a substitutive defect in the formation of hemoglobin in the red blood cells, producing a distinctive disease process. This disease was first scientifically recorded in 1910 by Dr. James Herrick. While examining the blood of a young West Indian student, he observed that many of the red blood cells were elongated with a curved shape instead of the normal round configuration. It was after similar repeated observations by other investigators that the descriptive term "sickle cell anemia" was used to describe this disease.

In sickle cell anemia, there is an alteration in the arrangement of the hemoglobin molecular structure. At the sixth position in each beta chain where the amino acid, glutamate should normally be incorporated, it is replaced by another amino acid, valine. This small change in the molecule results in great changes in its physical and chemical characteristics, so that in certain stressful conditions when the body is deprived of oxygen, the red cells then assume a crescent, banana, or sickle shape. This particular shape of the red cells makes its travel through the smaller blood vessels extremely difficult, producings an obstruction by creating a "log-jam", which may result in tissue and ultimately organ damage. Because of the abnormal hemoglobin and the shape of the red cells, they are quickly destroyed. This, combined with an inability of the body to produce sufficient numbers of new cells, produces a state of anemia.

The term sickle cell disease refers to all the clinically significant sickling disorders, since the degree of anemia may be variable and many potentially dangerous episodes can occur without an increase in the severity of the anemia.

Link to image source
Welcome to the Sickle Cell Disease Program of the University of Minnesota Health System (UMHS).

LABORATORY FINDINGS

Sickle Cell Trait (HbAS Disease)

Normal peripheral smear and bone marrow
No anaemia
Positive sickle cell test - when more than 25% HbS is present, sickling of RBC may be demonstrated in a blood suspension by deoxygenation of the blood
Positive solubility test for HbS - sickle test Hb is insoluble in a phosphate buffer solution
Hb electrophoresis - HbA 70% - 80%; HbS 30% - 40%; HbF <2%. Preponderance of HbA over HbS is a prerequisite for this diagnosis. (The reverse occurs in sickle cell beta-thalassemia)
Low fixed urine specific gravity and haematuria occur as a result of renal medullary microinfarcts.

Sickle Cell Anaemia (HbSS Disease)

Peripheral Blood

Sickle cells, ovalocytes, marked poikilocytosis, anisocytosis, nucleated RBC, Howell-Jolly bodies, target cells, spherocytes, polychromatophilia, stippled RBC, siderocytes. These abnormal cells appear in the circulation because the infarcted spleen is no longer able to remove them from the circulation.
Normocytic, normochromic anaemia (Hb 5 g/dl - 11 g/dl)
Increased reticulocytes (5% - 30%) - decreased during aplastic crisis
Increased WBC with left shift (10,000/ul - 30,000/ul) - does not necessarily signify an infection
Increased platelets (300,000/ul - 500,000/ul- may fall during an infarctive crisis

Bone Marrow

Hyperplasia of all elements but especially of RBC precursors
Increased iron deposits

Other Laboratory Findings

Positive sickle cell test - RBC transform to sickled form in an oxygen-poor environment
Positive solubility test for HbS - sickle cell Hb is insoluble in a phosphate buffer solution
Hb electrophoresis - HbS 80% - 100% - 100%, HbF 0% - 20%; because there is no normal beta polypeptide chain, there is no HbA.
Findings of haemolysis - increased unconjugated (indirect) bilirubin, LDH (especially LDH1 and LDH2), urine haemosiderin; decreased serum haptoglobin
Decreased sedimentation rate -reflects failure of sickle cells to undergo rouleaux formation
Decreased osmotic fragility- the sickle RBC resist haemolysis by hypotonic salt solutions
Increased serum alkaline phosphatase- result of bone and liver infarcts
Haematuria and fixed urine specific gravity (1.010-1.020)- due to repeated microinfarcts in the renal medulla
Laboratory findings of complications: infarction of lungs, spleen, kidneys; osteomyelitis, usually due to salmonella; iron deficiency anaemia (decreased ferritin and MCV)

HbSC Disease

Peripheral blood-sickle cells, may target cells (20%-85%); HbC crystals in 1%-2% of RBC, especially following splenectomy
Mild anemia
Slight reticulocytisis (about 3%)
Haemoglobin electrophoresis- HbS 40%-50%, HbC 40% - 50%, HbF 2%-15%,
HbA absent

Sickle Cell B-Thalassemia Disease

Many target cells (20%-40%)
Hypochromic, microcytic anaemia
Hb electrophoresis-complete beta-chain suppression: HbS50%-80%, HbF 2%-30%,HbA2 >3.6%; incomplete Beta-chain suppression:HbS 50%-80%, HbF 2%-20%, HbA 15%-35%, HbA2 >3.6%
Other laboratory findings are those of HbSS disease.

HAEMOGLOBIN C DISEASE

Haemoglobin electrophoresis showing (1) normal, (2) newborn, (3) Hb C trait (A-C), (4) Hb SC disease (SC), (5) sickle cell disease (SS), (6) sickle cell trait (A-S), (7) newborn, (8) normal.

Haemoglobin C disease (link to image source)
Glutamine in the 6th position of the beta globin chain is replaced by lysine. In the homozygous state (HbC disease), mild anaemia and splenomegaly is present. The condition is found in Africa and the Middle East.

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LABORATORY FINDINGS

HbAC Trait

Peripheral blood- moderately increased number of target cells (5%-30%)

Hb electrophoresis- HbA 55%-70%, HbC 30%-45%, HbA2 slightly increased

HbCC Disease

Peripheral Blood

Many target cells (about 90%), variable microspherocytes,polychcromatophilia, a few RBC contain tetragonal HbC crystals. The cryatals increase up to 10% following splenectomy and after incubation in 3% NaCl.
Mild normocytic anemia (Hb 8 g/dl-12 g/dl)

Bone Marrow

Normoblastic hyperplasia

Other Laboratory Findings

Haemoglobin electrophoresis - HbC 95% - 100%, HbF 0% - 5%, HbA absent
Findings of slight haemolysis - increased reticulocytes (2% - 10%), LDH, unconjugated bilirubin
Osmotic fragility test shows two cell populations; target cells have decreased fragility and microspherocytes have increased fragility.

HbSC Disease

See Sickle Cell Disease.

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