MLAB 2401: Clinical Chemistry Keri Brophy-Martinez Chapter 5: Hemoglobin Production Disorders.

MLAB 2401: Clinical ChemistryKeri Brophy-Martinez

Chapter 5: Hemoglobin Production Disorders

Iron Deficiency

• Lab Features– Microcytic, hypochromic anemia– Anisocytosis, poikilocytosis– Total iron and Percent saturation decreased– TIBC increased

Hemosiderosis

• Excessive levels of iron in storage

Hemochromatosis

• Characterized by an increased rate of absorption and less ferritin production

• Excessive iron deposits in organs• Patient develops bronze color in the tissues• Total iron, percent saturation increased• TIBC decreased

Iron Status in Disease StatesCondition Serum Iron Transferrin Ferritin % SaturationIDA Decreased Increased Decreased Decreased

Iron Overdose Increased Decreased Increased Increased

Hematochromatosis Increased Slight Decrease Increased Increased

Malnutrition Decreased Decreased Decreased Variable

Chronic anemia Decreased Normal/decreased

Normal/increased

decreased

Acute liver disease Increased Variable Increased Increased

Case Scenario #1

• A 40-year-old female is scheduled to have an elective surgery. Her physician ordered a routine CBC pre-op. The following test results were obtained:

Test Result Reference Range

Hgb (g/dL) 10 12-16.0

Hct (%) 29.9 42-52

MCV (fL) 75 80-100

MCHC (g/dL) 30 32-36

WBC (x 103/L) 6.0 4.5-11

Plts (x 109/L) 200 150-450

Case Scenario #1

• On review of her blood smear, the technician noted target cells.

• What other types of morphology would we expect to see on this patient?

• The physician then ordered a serum iron, ferritin and TIBC level.

Case Scenario #1

• Below are the results on the additional tests:• What is her diagnosis?

Test Result Reference Range

Serum iron ( µg/dL) 20 65-165

Ferritin ( µg/dL) 5 20-200

TIBC ( µg/dL) 550 260-440

Hemoglobin Disorders

• Refer to Hematology notes– Chapter 10: Hemoglobinopathies– Chapter 11: Thalassemia

Porphyrin Disorders= Porphyrias

• Inherited or Acquired• Enzyme deficiencies resulting in

overproduction of heme precursors in bone marrow or liver

Porphrias

• Classification– Based on• Specific enzyme deficiency• Hepatic vs erythropoietic• Cutaneous vs neurologic

Porphyrias

• Clinical symptoms– Cutaneous photosensitivity– Itchy skin– Hyperpigmentation– Inflammatory reaction occurs on exposure to

ultraviolet light– Neurologic abnormalities due to increased ALA

and PBG

Porphyrin Conditions• Secondary Conditions

– Porphyrinuria• Increase in coproporphyrin production• Causes

– Lead intoxication– Liver damage– Infection– Accelerated erythropoiesis

– Porphyrinemia• Increase in erythrocytic protoporphyrin concentration• Causes

– Lead intoxication– Iron deficiency– Impaired Iron absorption– Chronic infection

Myoglobin

• Elevations– Acute myocardial– Renal failure– Vigorous exercise– Electric shock– Intramuscular injections

LEAD

• Clinical Features– Children• CNS symptoms: headache ,clumsiness, seizures,

behavioral changes• GI symptoms: Abdominal pain, colic, constipation

– Adults• Peripheral neuropathies, motor weakness, anemia

Case Scenario #2

• A mother brings her active 2-year-old son to the pediatrician for a routine visit. The physician orders a CBC. Below are the results:

Test Result Reference Range

Hgb (g/dL) 10.2 14-17.4

Hct (%) 30.6 36-46

Case Scenario #2

• The mother reports that her son has had some constipation and abdominal pain. The child does eat well, and the mother gives the child a vitamin supplement, which includes iron

• The mother did mention that they live in an older home that is in need of repainting.

• The physician orders further testing…

Case Scenario #2

• Results of testing

Test Result Reference Range

Serum iron 120 65-165

Ferritin 150 20-200

Whole blood lead (µg/dL)

60 < 10

Erythrocyte protoporphyrin (µg/dL)

150 17-77

What is the diagnosis?

• Lead Poisoning• How does this occur?• Lead inhibits certain

enzymes in the heme synthesis pathway

Case Scenario #2

• IDA was ruled out based on the serum iron and ferritin levels