REVIEW 1: COMMON LABORATORY TESTS

RBC

The number of RBCs found in a cubic millimeters of whole blood

RBC normal range

• Female: 3.5 - 5 million/mm3

• Male: 4.3 - 5.9 million/mm3

RBC normal range

• Female:

• Male:

Anemia

Low RBC - possible causes / associated conditions?

Hematocrit

The number of RBCs in 100 mL of blood reported as a %

Hematocrit normal range

• Female: 37 - 47%

• Male: 42-52%

Hematocrit normal range

• Female:

• Male:

• Polycythemia vera

• Dehydration

• Vitamin B9 and B12 deficiencies

High hematocrit - possible causes / associated conditions?

• Iron deficiency anemia (IDA)

• Overhydration

• Blood loss

Low hematocrit - possible causes / associated conditions?

Hemoglobin

The O2-carrying protein in RBCs

Hemoglobin normal range

• Female: 12 - 16 g/dl

• Male: 13 - 18 g/dl

Hemoglobin normal range

• Female:

• Male:

• Blood loss

• Iron deficiency anemia (IDA)

Low hemoglobin - possible causes / associated conditions?

Mean cell hemoglobin (MCH)

The average RBC Hgb content

26 - 34

Mean cell hemoglobin normal range

Hypochromic anemia; associated with iron deficiency anemia (IDA)

< 26 mean cell hemoglobin (MCH) - interpretation + associated condition?

Hyperchromic anemia; associated with vitamin B9 and B12 deficiencies, hemolytic anemia

> 34 mean cell hemoglobin (MCH) - interpretation and associated conditions?

Mean cell hemoglobin concentration (MCHC)

The amount of Hgb per volume of RBCs

31 - 37

Mean cell hemoglobin concentration (MCHC) normal range

Hypochromic anemia; associated with iron deficiency anemia

< 31 mean cell hemoglobin concentration (MCHC) - interpretation + associated condition?

Hyperchromic anemia

> 37 mean cell hemoglobin concentration (MCHC) - interpretation?

Mean cell volume (MCV)

The average volume of the individual RBCs

80 - 100

Mean cell volume (MCV) normal range

Microcytic; associated with iron deficiency anemia

< 80 mean cell volume (MCV) - interpretation + associated condition?

Macrocytic; associated with vitamin B9 and B12 deficiencies

> 100 mean cell volume (MCV) - interpretation + associated condition?

Reticulocytes

The immature RBCs that contain residual RNA and protoporphyrin but no nucleus

0.1 - 2.4%

Reticulocytes normal range

• Blood loss

• Hemolytic anemia

• (Polychromasia?)

> 2.4% reticulocytes - possible causes / associated conditions?

Decreased reticulocytes

< 0.1% reticulocytes - possible causes / associated conditions

Erythrocyte sedimentation rate (ESR)

Measures the rate of RBC settling of whole, uncoagulated blood over time

Erythrocyte sedimentation rate normal range

• Female: 1-30 mm/hr

• Male: 1-13 mm/hr

Erythrocyte sedimentation rate normal range

• Female:

• Male:

• Inflammation

• Infection

• Tissue necrosis or infarction

• Malignancy

• Rheumatoid collagen diseases

High erythrocyte sedimentation rate (ESR) - possible causes / associated conditions?

Activated partial thromboplastin time (aPTT)

Assesses the intrinsic clotting pathway

24 - 37 sec

Activated partial thromboplastin time (aPTT) normal range

Used to monitor heparin therapy (aPTT = 1.5 - 2.5 xx control)

Activated partial thromboplastin time (aPTT) - use?

Prothrombin time (PT)

Assesses the extrinsic clotting pathway

8.8 - 11.6 sec

Prothrombin time (PT) normal range

8.8 - 11.6 sec

Prothrombin time (PT) normal range

Used to monitor warfarin therapy (INR = 2-3)

Prothrombin time (PT) - use?

International normalized ratio (INR)

More standardized expression of PT

= (PT patient / PT control)^international sensitivity index

International normalized ratio (INR) formula

WBC (leukocytes)

Number of WBCs found in a cubic millimeters of whole blood

4000 - 11000 WBC/mm3

WBC normal range

Bacterial infection (leukocytosis)

High WBC - possible causes / associated conditions?

Bone marrow depression (leukopenia)

Low WBC - possible causes / associated conditions?

neutrophils

Are the most common type of WBC. Produced in the bone marrow, these immune cells act as the body’s first responders, rushing to sites of infection or injury to trap and destroy BACTERIA and FUNGI

50 - 70%

Neutrophils (polymorphonuclear leukocytes (PMN)) normal range

3 - 5%

Bands (immature neutrophils) normal range

• Infections

• Tissue necrosis

• Inflammatory disease

• Metabolic disorders

• Myelogenous leukemia

• Rickettsial diseases (neutrophilic leukocytosis)

High neutrophils - possible causes / associated conditions?

Overwhelming infection of any type (neutropenia)

Low neutrophils - possible causes / associated conditions?

basophils

Are the rarest type of WBC. Produced in the bone marrow, they RELEASE HISTAMINE AND HEPARIN during allergic reactions and inflammation to fight parasites and help heal damaged tissue

0 - 1%

Basophils normal range

• Chronic myelogenous leukemia (CML)

• Chronic hypersensitivity states

• Systemic mast cell disease (basophilia)

High basophils - possible causes / associated conditions?

Eosinophils

Are a type of specialized WBC (granulocyte) produced in the bone marrow that plays a key role in fighting PARASITIC INFECTIONS, regulating INFLAMMATORY RESPONSES, and managing ALLERGIC REACTIONS

0 - 5%

Eosinophils normal range

• Acute allergic reactions

• Parasitic infections (eosinophilia)

High eosinophils - possible causes / associated conditions?

Lymphocytes

Are a vital type of WBC that make up the body’s IMMUNE SYSTEM. Originate in the bone marrow and travel through the blood and lymphatic system to fight of infections, viruses, bacteria and abnormal tumor cells

20 - 40%

Lymphocytes normal range

Viral infection (lymphocytosis)

High lymphocytes - possible causes / associated conditions?

• Severe debilitating illness

• Immunodeficiency

• AIDS (lymphopenia)

Low lymphocytes - possible causes / associated conditions?

Monocytes

The LARGEST type of WBC and a core part of the body’s innate immune system

0 - 7%

Monocytes normal range

• TB

• Subacute bacterial endocarditis (monocytosis)

High monocytes - possible causes / associated conditions?

Platelets (thrombocytes)

Smallest formed elements in the blood; involved in blood clotting and responsible for initiating hemostasis

150 000 - 300 000/mm3

Platelets normal range

Moderate thrombocytopenia

Platelets < 100 000 - interpretation?

Severe thrombocytopenia

Platelets < 50 000 - interpretation?

Blood urea nitrogen (BUN)

A medical test that measures the amount of waste product (urea nitrogen) in your blood to check how well your kidneys and liver are working

8 - 18 mg/dl

BUN normal range

Renal disease

High BUN - possible causes / associated conditions?

Liver disease

Low BUN - possible causes / associated conditions?

Creatinine

Is a chemical waste product formed when muscles break down a compound called creatine, which the body uses for energy

0.6 - 1.2 mg/dl

Creatinine normal range

Renal failure

High creatinine - possible causes / associated conditions?

Creatinine clearance

Is the volume of blood plasma that your kidneys can clear of creatinine per unit of time. It serves as a direct estimate of the glomerular filtration rate (GFR) which measures how well your kidneys filter waste from the blood

80-120 ml/min

Creatinine clearance normal range

Renal failure

low creatinine clearance - possible causes / associated conditions?

Ccr = [(140-age)(mass in kg)(0.85 if female)] / 72 (serum creatinine in mg/dl)

Creatinine clearance formula

Creatine kinase

An enzyme that helps your body produce cellular energy

Creatine kinase normal range

• Female: 40-150 U/L

• Male: 60-400 U/L

Creatine kinase normal range

• Female:

• Male:

Myocardial necrosis (CK-MB)

High creatine kinase (CK) - possible causes / associated conditions?

Creatine kinase isoenzymes locations

• CK-MM: skeletal muscles

• CK-MB: heart

• CK-BB: brain

Creatine kinase isoenzymes locations

• CK-MM

• CK-MB

• CK-BB

Lactic dehydrogenase

Aid in diagnosing MI, hepatic disease, and lung disease

110 -210 U/L

Lactic dehydrogenase normal range

• LDH1: 17-27%

• LDH2: 28-38%

• LDH3: 18-28%

• LDH4: 5-15%

• LDH5: 5-15%

Lactic dehydrogenase isoenzymes normal range (as percentages of total LDH)

• LDH1 & LDH2: heart

• LDH3: lungs

• LDH4 & LDH5: liver and skeletal muscles

LDH isoenzymes - which tissues?

• MI

• Hepatic disease

• Lung disease

High lactic dehydrogenase - possible causes / associated conditions

Alkaline phosphatase (ALP)

Is a natural protein enzyme found throughout the body, with highest concentrations in the liver, bile ducts, and bones

Alkaline phosphatase (ALP) normal ranges

• Female: 30-100 U/L

• Male: 45-115 U/L

Alkaline phosphatase (ALP) normal ranges

• Female:

• Male:

• Biliary obstruction

• Paget's disease

  • disruption of normal bone remodeling process → excessive bone breakdown → chaotic, disorganized new bone growth

• Hyperparathyroidism

• osteomalacia

Alkaline phosphatase (ALP) - possible causes / associated conditions?

Alanine aminotransferase (ALT)

Serum glutamic-pyruvic transaminase (SGPT) relatively specific for liver cell damage

Alanine aminotransferase (ALT) normal ranges

• Female: 7-30 U/L

• Male: 10-55 U/L

Alanine aminotransferase (ALT) normal ranges

• Female:

• Male:

Liver diease (relatively specific for liver cell damage)

High ALT - possible causes / associated conditions?

Aspartate aminotransferase (AST)

Serum glutamic-oxaloacetic transaminase (SGOT)

Aspartate aminotransferase (AST) normal ranges

• Female: 9-25 U/L

• Male: 10-40 U/L

Aspartate aminotransferase (AST) normal ranges

• Female:

• Male:

• MI

• Liver disease

High aspartate aminotransferase (AST) - possible causes / associated conditions?

Cardiac troponins

Diagnosis of acute MI

• Troponin T: < 0.1 ng/mL

• Troponin I: < 1.5 ng/mL

• Troponin C

Cardiac troponins normal ranges

Cardiac troponins location

• Troponin T: cardiac and skeletal muscle

• Troponin I: cardiac muscle

• Troponin C: skeletal and cardiac muscle

Cardiac troponins locations

• Troponin T

• Troponin I

• Troponin C

135-147 mEq/L

Sodium normal ranges

Hypernatremia

High sodium - possible causes / associated conditions?

3.5-5 mEq/L

Potassium normal ranges

• Renal dysfunction

• Acidosis

• Dehydration

• Cellular breakdown (tissue damage, hemolysis, burns, infections)

• With the administration of spironolactone

High potassium - possible causes / associated conditions?