Clinical Lab Studies PDF

CLINICAL LABORATORY STUDIES Chapter 7: Part One HEMATOLOGY Composition of Blood Formed Elements – White blood cells (leukocytes) – Red blood cells (erythrocytes) – Platelets (thrombocytes) Plasma – Electrolytes – Clotting factors – Immunologic factors...

CLINICAL LABORATORY STUDIES Chapter 7: Part One HEMATOLOGY Composition of Blood Formed Elements – White blood cells (leukocytes) – Red blood cells (erythrocytes) – Platelets (thrombocytes) Plasma – Electrolytes – Clotting factors – Immunologic factors – Proteins – Lipids – Hormones All substances used by cells must be transported by plasma Serum is plasma with clotting factors removed Complete Blood Count (CBC) CBC includes RBC’s and WBC’s. WBC identifies different type of cells – Differential count RBC idices – number of cells present – Size/shape – hemoglobin (Hb)  WBC count 4.0 – 11.0 RBC Count Males: 4.20 – 6.00 Females: 3.80 – 5.20 Normal Hemoblobin (g/dL) Values Males: 13.5 – 18.0 Females: 12.0 – 15.0 Hematocrit % Males: 40 – 54 Females: 35 – 49 Platelet Count 150 - 450  White Blood Cells Primary role is to fight infection WBC in peripheral blood include 5 types Neutrophils Eosinophils Basophils Lymphocytes Monocytes White Blood Cell Functions Granulocytes include: – Neutrophils – Eosinophils – Basophils Differential tells what % of total WBC make up each cell type The specific cell type will change in value in response to the problem Neutrophils 50 to 70% of the WBC’s Also known as polymorphonuclear leukocytes Produced in bone marrow Enter blood then tissue to fight inflammation and infection Have a very short half-life Band – Immature neutrophil in the circulating blood Phagocytosis Eosinophils ▪ 1 to 3% of WBCs ▪ Large granules that stain bright red (acidophiles) ▪ Involved in immune system regulation ▪ Accumulate at allergic reaction site Basophils Large granules that stain dark blue or purple 0-1% of WBCs Contain Heparin – prevent coagulation of blood at sites of inflammation Basophils interact in allergic reactions and work similar to eosinophils Lymphocytes 20 to 45% of WBCs Lymphocytes can be divided into large granular lymphocytes and small lymphocytes – Large granular lymphocytes consist of the natural killer cells (NK cells) – Small lymphocytes consist of T cells and B cells Important line of defense against foreign microorganisms and cells T Cells and B Cells Major cellular components of the adaptive immune response T cells are involved in cell-mediated immunity B cells are primarily responsible for humoral immunity (relating to antibodies) Function:. Once they have identified an invader, the cells generate specific responses that are tailored to maximally eliminate specific pathogens or pathogen infected cells. – B cells respond to pathogens by producing large quantities of antibodies which then neutralize foreign objects like bacteria and viruses. Monocytes 2-11% of WBC’s In the tissue called macrophages Main function: phagocytosis Increase from stress or chronic inflammation Normal WBC count: 4.0 to 11 Leukocytosis Leukopenia WBC More specific exact cell Abnormalities type Neutrophilia Neutropenia Eosinophilia Basophilia Lymphocytosis Monocytosis Neutrophilia One of body’s first responses to infection and inflammation Left shift: immature cells (bands) released from bone marrow trying to respond to the infection.  A decrease in neutrophils Neutropenia Causes Increased Bone marrow destruction of the failure (primary) cells peripherally  Increase in eosinophils Elevated in Eosinophilia presence of: Parasitic infestation Allergic states Allergic Asthma  Increase in basophils Basophilia Associated with myeloproliferative neoplasms (MPNs) Reason for MPN Some genetic remains predisposition unknown shown Lymphocytosis Increase in lymphocytes Typical of viral infections Lymphocytopenia Decrease in lymphocytes HIV Trauma Increase in monocytes Characteristic of certain infections: Monocytosis TB Syphillis Typhoid fever Fungal infections Red Blood Cells ▪ Produced in the bone marrow ▪ Main component: Hb ▪ Primary function: carry oxygen ▪ Life span: approx. 120 days Protein that carries oxygen to the tissues Carries CO2 from the tissues to the lungs Hemoglobin Each RBC contains 200- (Hb or Hgb) 300 million Hgb molecules Hgb acts as a buffer to help maintain pH of blood  Hematocrit (Hct) http://upload.wikimedia.org/wikipedia/commons/thumb/4/43/Illu_blood_components.svg/230px-Illu_blood_components.svg.png Ratio of packed RBC volume to the volume of whole blood Normal: – Men: 40 to 54% – Women: 35 to 49% HEMATOCRIT RBC Indices 3 indices: – MCV: Avg. RBC size – MCH: Amount of Hb per red blood cell – MCHC: The amount of hemoglobin relative to the size of the cell (hemoglobin concentration) per red blood cell Values determine classification of anemias.  RBC ABNORMALITIES Anemia ▪ Reduction in RBC mass of the body ▪ Causes: – Blood loss – Deficiency in cell formation – Abnormal Cell formation – Chronic disease and aging ▪ Reduced Oxygen carrying capacity ▪ Iron deficiency Carboxyhemoglobin When CO binds with Hb Has an affinity of 210 times that of Oxygen COHb levels in smokers 5 to 7% Methemoglobinemia Methemoglobin – from chemical ingestion – O2 cannot combine with Hb – High oxygen saturation, low PaO2 Sulfhemoblobinemia Sulfur forms with Hb Imetrex for migraines Symptoms include: – a blueish or greenish discoloration of the blood, skin, and mucous membranes – even though a blood count test may not show any abnormalities in the blood  Increase RBC count, Hb, and Hct Primary Polycythemia: not common Polycythemia Secondary Polycythemia: most common Chronic hypoxemia in COPD Heavy smokers  CO binds with Hb O2 carrying capacity reduced Polycythemia Hypoxemia/Hypoxia Stimulates kidney to produce erythropoietin Bone marrow produces RBC  Normal 1% of total RBC’s Immature RBC’s: Newborns will have slightly higher Reticulocyte values Indicate extreme stress on bone marrow to produce RBC’s Helpful in evaluating anemias Hemostasis Ability to prevent hemorrhage Plasma to form a fibrin clot should be < 1 minute Different tests to assess the interaction of protein and platelets in plasma: – Platelet count – APTT – PT/INR Before obtaining an arterial blood gas (ABG), look to see if coagulation studies have been performed Platelet Count Important for blood clot formation. Platelets are a natural source of growth factors Circulate in the blood of mammals and are involved in hemostasis, leading to the formation of blood clots Thrombocytopenia: low Thrombocytosis: high  Evaluates time it takes extrinsic blood factors to form a clot Body’s defense against hemorrhage Normal 12-15 seconds Prothrombin Common causes of a prolonged Time (PT) PT include: vitamin K deficiency hormones drugs including hormone replacements and oral contraceptives disseminated intravascular coagulation (a serious clotting problem that requires immediate intervention) liver disease use of the anti-coagulant drug warfarin  Used to monitor heparin IV Excessive bleeding or bruising APTT 30-40 seconds clotting time Initial test if bleeding problems are suspected CHEMISTRY Chapter 7: Part 2 Electrolytes Electrolytes are free ions in body fluids and allow this fluid to conduct an electrical current Extremely important when managing patients with fluid balance problems Most commonly measured electrolytes Na+: Sodium K+: Potassium Cl-: Chloride HCO3-: Bicarbonate Major cation (+) of extracellular fluid. 135 - 145 mmol/L Renal regulation, influenced by hormones, regulates sodium Sodium Adrenal gland: Aldosterone Normal loss Insensible-12 mL/kg (Na+) Sweat-Variable Urine-300-1500 mL/day Hypothalamus: antidiuretic hormone (ADH) Hypernatremia > 147 mEq/L Hypernatremia: Loss of water without salt Profuse sweating, diarrhea, renal diseases, prolonged hyperpnea. Insufficient water intake Hormonal abnormalities Clinical manifestations: Excessive thirst Dry, sticky mouth. Hypernatremia Hyponatremia Hyponatremia < 137 mEq/L Hyponatremia: Excess sodium loss compared to water loss. Diuretic therapy, diarrhea, nephrosis. Severe hyponatremia: 5.0 – Decreased serum K+ mEq/L – Decreased intake K+ above 10 mEq/L, Disturbs cardiac, skeletal cardiac arrest muscle, and G-I systems Metabolic Acidosis K+ moves out of cell in exchange of H+ moving into cell to buffer extracellular fluid and return fluid to normal pH Extracellular levels of K+ high. Correcting the acidosis will correct the hyperkalemia Metabolic Alkalosis Metabolic alkalosis causes H+ to move out of cell to extracellular fluid K+ moves into cell to correct the pH. Hypokalemia Chloride Major anion (-) of extracellular fluid 98 - 107 mEq/L Hypochloremia: – Prolonged vomiting (loss of HCL) – Chronic respiratory acidosis Hyperchloremia: – Prolonged diarrhea – Kidney diseases  Normal 22-26 mEq/L Plays a major role in acid- base buffer system Increased levels caused from: Bicarbonate Metabolic alkalosis (HCO3¯ ) Compensation for respiratory acidosis Decreased levels caused from: Metabolic acidosis Compensation for respiratory alkalosis Other electrolytes Calcium: Ca2+ Phosphorus: PO4- Magnesium: Mg2+  ANION GAP  Balance between cations and anions in the extracellular fluid.  Not all anions are measured so this is referred to as the anion gap.  Potasium not measured-in low levels so will not effect the gap.  AG= ( [Na+] ) − ( [Cl−]+[HCO3−] )  Calculating the anion gap helps define the cause of metabolic acidosis  High gap  Ketoacidosis-diabetes, Lactic acidosis-low oxygen  Low Anion Gap  Common conditions that reduce serum albumin hemorrhage, intestinal obstruction and liver cirrhosis.  Normal gap is 8-16 mEq/L ELECTROLYTES IN SWEAT To assist in diagnosis of CF. Normal sweat Cl is < 60 mEq/L CF – Decrease ability to reabsorb Na+ and Cl- – Na+ and Cl- concentration is high: A sweat chloride test result less than or equal to 39 mEq/L in an infant over 6 months old probably means cystic fibrosis is not present. A result between 40 - 59 mEq/L does not give a clear diagnosis. Further testing is needed. If the result is 60 mEq/L or greater, cystic fibrosis is present ELECTROLYTES IN SWEAT Blood Urea Nitrogen (BUN) and Creatinine Most common screening tests in assessing renal function. Measures the amt of nitrogen that comes from waste product urea. Urea is a waste product made in intestines and liver when product breaks down (end product of protein). Urea is then excreted by kidneys Urea is constantly excreted by kidneys. – Normal: 7-20 mg/dL – Increased retention: Protein intake, hydration state, decreased renal perfusion. BUN > 60 indicates moderate to severe degree of kidney failure from dehydration Blood Urea Nitrogen (BUN) and Creatinine Creatinine is constantly formed within muscle tissue and filtered by kidneys. – Normal: 0.7-1.3 mg/dL – Creatinine is a waste product from breakdown of creatine which converts food into energy. – With kidney damage, creatinine in blood increases and in urine decreases In renal failure: – Increased BUN and creatinine. – Metabolic acidosis. – Increased respiratory rates. Enzymes Responsible for most chemical reactions. Found in all cells Released into blood post tissue damage. Therefore increase in certain enzyme gives clue to specific organ Isoenzymes: specific for organs.  Aspartate aminotransferase (AST) Highest concentration in heart and liver tissue. Highest level: acute hepatitis. High levels on second day of MI. Alanine aminotransferase (ALT) Liver enzyme therefore liver damage Alkaline phosphatase (ALP) Useful in evaluating liver disease and bone disease Acid phosphatase (ACP)  High concentrations in the prostate gland.  Significant high levels almost exclusively in metastatic prostate cancer.  Prostate Specific Antigen (PSA) identified in blood and is used to screen for prostate cancer. Lactic dehydrogenase (LDH) High concentrations in heart, liver, skeletal muscle, brain, kidney, and RBC’s. High levels with cancer, moderate with MI. Creatine phosphokinase (CPK) The CPK isoenzymes test measures the different forms of creatine phosphokinase (CPK) in the blood. CPK is an enzyme found mainly in the heart, brain, and skeletal muscle. Primarily elevated in MI (first 8h) and skeletal muscle disease. Other Enzymes  Amylase  From pancreas and salivary glands.  Elevated plasma and urinary levels few hours after pancreatitis.  Lipase  Acute pancreatitis.  Rise more slowly than amylase.  Myoglobin-increase with acute MI –also found skeletal and smooth muscle Brain Natriuretic Peptide (BNP) Amino acid polypeptide (hormone) secreted by the ventricles of the heart in response to excessive stretching of myocytes Type – A, B and C type – Have an effect on renal and circulatory function B type stored in brain and also in the heart Helps rule out congestive heart failure Able to differentiate dyspnea from cardiac origin and pulmonary origin Normal values with pulmonary dyspnea, abnormal with cardiac dyspnea due to congestive heart failure Brain Natriuretic Peptide (BNP) Normal: < 100 picograms per milliliter (pg/ml) no heart failure is present. Abnormal: – >100 pg/mL mild heart failure. – > 600 pg/mL moderate to severe heart failure. Glucose Produced from digestion of carbs. Absorbed in blood and metabolized for energy production. Normal “fasting” plasma level: 70-105 mg/dL. (Type II diabetes has high levels) Insulin is necessary for cells to use glucose. Type I diabetes-decreased insulin levels Type I Diabetes-Childhood  Normally insulin moves sugar into cells  Diabetes-glucose builds up in blood  Overflows in urine, moves out of body in urine  Main source of fuel is gone.  Type I-unable to produce insulin Glucose Type II diabetes (most common) – Slow release of insulin in response to high blood sugar and insulin deficiency. – Both types have decrease use of glucose and high blood glucose known as: Hyperglycemia -> 240 mg/dL: – Hyperglycemia along with acidosis by accumulation of ketoacids called ketoacidosis. Significant hypoglycemia: < 45 mg/dL – Sweating, shaking, weakness, fainting Glucose Gestational diabetes – Occurs during pregnancy – Goes away after birth – Hormones reduce insulin production – Detected when fetus is 24-28 weeks – Baby may be bigger because of glucose Gestational Diabetes  Protein Major serum protein is albumin (60%). – Transport of drugs, hormones, electrolytes. – Maintenance of oncotic pressure for blood keeps blood from leaking out of vessels – Keeps water component of plasma in vascular spaces. – Most common tests for protein is albumin and total protein  Protein Total protein level decreased in liver disease and malnutrition. Hypoalbuminemia – loss of fluid from vascular space and causes edema – pulmonary edema Transports – Thyroid hormone – Unconjugated bilirubin  Fuel storage Development of hormones and cell walls Two common lipids measured – Triglycerides > 35 yrs (140-150 mg/dL) Main storage of lipids. Fatty tissue mainly made up of this. – Cholesterol for adults 20-60 yrs. (160-200 mg/dL) Important in synthesis of hormones, cell development and insulate nerves.  Lipids Lipoproteins-more emphasis placed on this -HDL, LDL  Drug Monitoring Some drugs have narrow therapeutic window – Too little no good, too much no good – Each person metabolizes drugs differently – These drugs require close monitoring – Common drugs include Cardiac-digoxin Anticonvulsants-phenytoin Antibiotics-gentamycin Bronchodilators-theophylline Drug Monitoring Theophylline Used to treat bronchospasm – Normal range: 5-15 mg/mL – Toxic level: >15 mg/mL Blood levels are drawn to assure proper levels Toxicity symptoms include: Nausea Vomiting Loss of appetite Abdominal pain