Lab Data Part 2 PDF

## E) Urinalysis - Urinalysis is a useful laboratory test that enables a clinician to identify patients with a wide variety of disorders, especially those associated with the renal system. - It is an inexpensive and noninvasive procedure. ## Urine Analysis | | Chemical Test | Microscopic Examinati...

## E) Urinalysis - Urinalysis is a useful laboratory test that enables a clinician to identify patients with a wide variety of disorders, especially those associated with the renal system. - It is an inexpensive and noninvasive procedure. ## Urine Analysis | | Chemical Test | Microscopic Examination | |---|----------------|----------------------------| | 1 | pH | RBCs | | 2 | Specific gravity | WBCs | | 3 | Glucose | Epithelial cells | | 4 | Proteins | Crystals | | 5 | Ketones | Casts | | 6 | Bilirubin | | | 7 | Uroblinogen | | | 8 | Blood | | | 9 | Nitrite | | - Normal urine color should range from clear to dark yellow, with some cloudiness due to the presence of phosphates or urates. - If urine is reddish orange, this may indicate the presence of blood or be due to drugs such as rifampicin. - Other drugs that may cause urine discoloration include: - Amitriptylline, which can cause a blue-green color. - Chloroquine and Metronidazole which can cause brown discoloration of urine. - The kidney normally prevents larger protein molecules from escaping into the urine. - Small traces of protein are a common clinical finding and have no implications. However, the presence of protein (proteinuria) > 150 mg/day indicates dysfunction or renal disease. - Normally, glucose is actively reabsorbed into the body by the kidney up to a maximum threshold (approximately 180 mg/dL blood glucose). As such, a high level of glucose in the urine is an indication of diabetes mellitus or the need for improved glucose control. ## F) Liver Function - The liver is the largest solid organ in the human body. - It plays a central role in all of the body's biochemistry. - Liver function tests can give a clearer picture of any of the functions of the liver: synthesis, excretion, or detoxification. - These tests can also help indicate liver injury. ## 1) Serum Bilirubin - Bilirubin is a reddish-yellow pigment which is produced during the normal breakdown of RBC. - It is excreted bile, into the duodenum. Bilirubin circulates in the bloodstream in two forms: - Indirect (unconjugated) bilirubin, which does not dissolve in water, and thus cannot be measured. As such, it is derived from both the total and direct bilirubin measurements. - Direct (or conjugated) bilirubin: The levels can be measured directly from the blood. - Normal values: - Total bilirubin: 0.1 to 1.2 mg/dL - Direct bilirubin: less than 0.3 mg/dL ## Clinical Significance - Levels of serum bilirubin can help clinicians identify liver cell damage in a patient. - If there was an increase in total bilirubin and indirect bilirubin, but not direct bilirubin, this could be an indication of RBC hemolysis, because the liver produces direct bilirubin, which is unaffected. - Meanwhile, elevated levels of direct bilirubin may be associated with hepatocellular diseases. - In cases where there is excessive total bilirubin, patients will exhibit signs of jaundice, which could result in kernicterus in infants and children. ## 2) Urine Bilirubin and Urobilinogen - As discussed previously, conjugated bilirubin is excreted with the bile into the duodenum, where the conjugated bilirubin is converted by bacteria into urobilinogen. - Most of the urobilinogen is excreted in the feces, but some is reabsorbed into the blood and goes either into the liver for reexcretion in the bile, or the urine. - In patients with complete bile duct obstruction, no urobilinogen is formed. Therefore, the stools will become gray-white or clay-colored due to the lack of bilirubin. - In addition, as conjugated bilirubin cannot be excreted into bile, it will be reabsorbed into the bloodstream and thus spilled into the urine, resulting in high levels of direct bilirubin in the blood. - Nevertheless, false-positive results may occur in patients is taking phenazopyridine or phenothiazines. - Thus, it is important for pharmacists to note this, since both the drugs, and bile pigments in urine can cause an orange discoloration. ## 3) Alkaline Phosphatase - Alkaline phosphatase (ALP) is an enzyme produced mainly in the liver and bone, but can also be found in the kidneys, intestines, and placenta. - It is excreted by the liver into the bile, and thus, it is a sensitive indicator of biliary obstruction. - Normal values: 30-120 U/L (depending on age and assay). ## Clinical Significance - Increased concentrations of alkaline phosphatase may indicate hepatitis, liver cirrhosis, hepatic cancer, or gallstones. - High ALP levels may indicate an overreactive parathyroid gland, rickets, Paget's disease, or bone cancer. ## 4) Aminotransferases: - Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT) - AST=SGOT - ALT=SGPT - These enzymes are located inside the hepatocytes, and function primarily to assist with various metabolic pathways. - Any injury to these tissues will release the aminotransferases into the systemic circulation and result in their elevation. - Of the two enzymes, ALT is considered a more specific marker of liver disease than aspartate AST. As such, they are commonly used to assess for hepatocellular injuries, such as hepatitis. - Normal values: 0-35 U/L (depending on age and assay). ## Clinical Significance - Increased concentrations are associated with hepatitis, and alcoholic liver diseases. - Elevated levels could also be seen with drug toxicity or interference with drugs such as acetaminophen, erythromycin, or levodopa. ## g) Thyroid Function -The gland produces three hormones, namely: - Triiodothyronine or T3 - Tetraiodothyronine also called thyroxine or T4 - Calcitonin - The two main hormones are T3 and T4, produced in the follicular epithelial cells of the thyroid, with iodine being one of the major components of both hormones. ## 1) Thyroid-Stimulating Hormone - The thyroid-stimulating hormone (TSH) test, and the T4 test, are the most common thyroid function tests. - The TSH test measures the level of circulating TSH, and is used to screen for, and diagnose thyroid disorders. It is also used for routine monitoring during hypothyroidism treatment. - Normal values: 0.5 to 5 microunits per milliliter (µU/mL) -Clinical Significance - Elevated TSH level is most often due to hypothyroidism - Reduced TSH level is most often due to hyperthyroidism ## 2) Triiodothyronine - T3 is the more potent form of circulating thyroid hormone. It is usually used in the diagnosis of hyperthyroidism. - Normal values: 1.2-3.1 mIU/L. - Clinical Significance - High levels of T3 are usually seen in patients with hyperthyroidism, as well as in those with Graves' disease. Conversely, decreased T3 levels are associated with hypothyroidism and/or malnutrition. - Some drugs, such as corticosteroids and propranolol, which decrease the conversion of T4 to T3, may result in reduced levels of T3. - It is important to take into consideration the effect of amiodarone on thyroid function. Amiodarone, due to its high iodine content, may induce hypothyroidism or thyrotoxicosis. Thus, amiodarone should be avoided in patients on medications to manage thyroid abnormalities. ## H) Lipid Profile - The lipid profile is commonly used as part of a cardiac risk assessment, to determine an individual's likelihood of heart disease, and to assist in decision-making on what treatment may be best. - it primarily comprises the measurement of: - Total cholesterol (TC) - High-density lipoprotein cholesterol (HDL-C) - Low-density lipoprotein cholesterol (LDL-C), - Triglycerides (TGs). ## 1) Low-Density Lipoprotein Cholesterol - Approximately 60%-70% of cholesterol in the body is carried as LDL-C in the blood. - Lipoproteins are essential for the transportation of cholesterol, which in turn is vital for the biosynthesis of bile acids, vitamin D, and steroid hormones. - Dietary intake and endogenous hepatic production are the two primary sources of cholesterol. - Normal values: Values for LDL-C can be divided into several categories: - Optimal: <100 mg/dL or < 2.6 mmol/L. - Near optimal/above optimal: 100-129 mg/dL or 2.6-3.3 mmol/L. - Borderline high: 130-159 mg/dL or 3.4-4.1 mmol/L. - High: 160-189 mg/dL or 3.1-4.9 mmol/L. - Very high: >190 mg/dL or > 4.9 mmol/L. - Clinical Significance - A higher value is associated with an increased risk for the development of CAD, and intervention may be needed. ## 2) High-Density Lipoprotein Cholesterol - HDL-C is produced and secreted by the liver and intestine. - HDL-C acts as transporters for cholesterol from tissues to the liver. - High levels of HDL-C are deemed desirable due to their inverse relation with coronary risk. Hence, HDL-C is commonly called "good cholesterol". Because of this inverse relation with the incidence of atherosclerosis. - Normal values: - Low: < 40 mg/dL - Optimal: > 60 mg/dL - Clinical Significance - In general, elevated HDL levels are ideal, because they are associated with a decreased risk for cardiovascular diseases. - HDL levels can be decreased in association with recent illness, starvation, stress, smoking, obesity, lack of exercise, hypertriglyceridemia, or may be due to some medications (e.g., thiazide diuretics, steroids, beta blockers) - Regular aerobic exercise, smoking cessation, a decrease in body mass index, and mild therapy with HMG-CoA reductase inhibitors (i.e., statins), may increase HDL-C levels. ## 3) Triglycerides - It is the most abundant dietary lipid compound found in the daily diet. - Normal values: There are currently no targets for serum TG levels, but levels below 150 mg/dL are considered desirable. | Cause | Increase LDL-C | Increase TG | |---|---|---| | Medications | Amiodarone, cyclosporine, diuretics, glucocorticoids | Anabolic steroids, atypical antipsychotics, ẞ-blockers, bile acid sequestrants, glucocorticoids, hormone therapy, protease inhibitors, raloxifine, retinoic acid, sirolimus, tamoxifen, thiazides | | Dietary influences | Saturated or trans fats, weight gain, anorexia | Very low-fat diets, high carbohydrate intake (refined), excess alcohol, weight gain | | Disease states and medical conditions | Nephrotic syndrome, biliary obstruction, hypothyroidism, obesity, pregnancy | Poorly controlled diabetes, hypothyroidism, obesity, pregnancy, nephrotic syndrome, chronic renal failure, lipodystrophies | ## I) Cardiac Enzymes ## 1) Creatinine Kinase (CK) - CK levels can be further divided into its isoenzymes, depending on where they originate from; muscle (CK-MM), brain (CK-BB), and cardiac tissue (CK-MB). - Making up 15%-30% of the total CK in the heart muscle, CK-MB is found mostly in the myocardium, whereas a much smaller proportion is found in the skeletal muscle. - CK-MB is sensitive and very specific to myocardial injury. - Normal values: The normal range of CK-MB is 3%-5% of total CK. ## Clinical Significance - Following the onset of acute myocardial injury, CK-MB begins to rise in 4-6 h, and returns to baseline level after 36-48 h. - Therefore, CK-MB is also a good marker of acute myocardial injury, reinfarction, or infarct extension. - CK-MB can be used to indicate successful reperfusion after fibrinolysis, estimate infarct size, and predict infarct-related mortality. ## 2) Troponin - Troponins are protein molecules and are part of the cardiac and skeletal muscle. Without cardiac myocyte damage, cardiac troponin levels do not increase in the presence of skeletal damage. - It is unlike CK-MB, which can be increased on injury to these tissues, potentially leading to false-positive results. Hence, troponin testing is more reliable than CK-MB testing in that sense. ## Clinical Significance - In healthy patients, troponins are undetectable, although this may not be the case as more sensitive assays become available. - In patients with MI, a time lag is seen before troponin elevations can be detected. Therefore, the markers should be serially monitored, should there be suspicion for the acute coronary syndrome. - Normally three sets of cardiac enzymes are checked. - The initial recommendation is to assess the markers every 3 hours until the expected peak is reached. - It is important to note some of the analytical interfering factors that may lead to falsely elevated troponin results. - Examples of such items include: - A specimen with incomplete clotting (often seen in patients with coagulopathy or those on anticoagulant therapy) - Elevated bilirubin levels - Markedly elevated alkaline phosphatase levels ## J) Amylase - Amylase is an enzyme that helps digest carbohydrates. - It is made in the pancreas and the glands that make saliva. - When the pancreas is diseased or inflamed, amylase releases into the blood. - The normal range is 40 to 140 units per liter (U/L) - Increased blood amylase level may occur due to: - Acute pancreatitis - Cancer of the pancreas, ovaries, or lungs - Cholecystitis - Gallbladder attack caused by disease - Infection of the salivary glands (such as mumps) or a blockage - Intestinal blockage - Pancreatic or bile duct blockage - Decreased amylase level may occur due to: - Cancer of the pancreas - Damage to the pancreas with pancreatic scarring - Kidney disease - Toxemia of pregnancy ## K) Blood Glucose | |Normal| Prediabetes | Diabetes Mellitus | |---|---|---|---| | FBG | < 100 mg/dl | 100-125 mg/dl | ≥ 126 mg/dl | | OGTT | < 140 mg/dl | 140-199 | ≥ 200 mg/dl | | A1C | < 5.7% | 5.7-6.4% | ≥ 6.5% | - OGTT: Plasma glucose concentration obtained 2 hours after a 75-g oral glucose ingestion. - A1C values may be inaccurate in patients with anemia, chronic malaria, sickle cell anemia, pregnancy, or significant blood loss or recent blood transfusion. - The diagnosis of both T1D and T2D requires: - Two abnormal tests showing hyperglycemia and can be obtained from the same sample (using two of the above criteria) or in two separate test samples (can be the same type of test) - Random plasma glucose (≥ 200 mg/dl + symptoms of hyperglycemia (polyuria, polydipsia, and unexplained weight loss.) ## HOMA-IR (Homeostasis Model Assessment of Insulin Resistance) - HOMA-IR is a useful, validated method for evaluating insulin resistance (IR). - IR is reduced physiological response of the peripheral tissues to the action of insulin. - It is one of the major causes of type II DM and compensatory hyperinsulinemia with consequent development of atherosclerotic cardiovascular disease. Therefore, a reliable measure of IR is important for the prediction of the metabolic syndrome (glucose intolerance, hypertension, central obesity, elevated serum TG and low serum HDL cholesterol.) ## INTERPRETATION OF HEMODYNAMIC PARAMETERS | Parameter | Calculation (If Applicable) | Normal Range | |---|---|---| | Systolic blood pressure (SBP) | | 90-140 mm Hg | | Diastolic blood pressure (DBP) | | 60-90 mm Hg | | Mean arterial blood pressure (MAP) | [SBP + (2 x DBP)]/3 | 70-100 mm Hg | | Systemic vascular resistance (SVR) | 80 [(MAP - CVP)/CO] | 800-1200 dynes/s/cm³ | | Heart rate (HR) | | 60-80 beats/min | | Cardiac output (CO) | HR × SV | 4-7 L/min | | Cardiac index (CI) | CO/BSA | 2.5-4.2 L/min/m² | | Stroke volume (SV) | CO/HR | 60-130 mL/beat | | Pulmonary capillary wedge pressure (PCWP) or pulmonary arterial occlusion pressure (PAOP)| | 5-12 mm Hg | | Central venous pressure (CVP)| | 2-6 mm Hg | | Lactic acid | | < 1 mmol/L | | Central venous oxygen saturation (Scvo₂) | | 70%-75%| - BSA = body surface area. ## 1) MAP - Normal MAP is 70-100 mm Hg. - MAP is an indication of global perfusion pressure; a MAP of at least 65 mm Hg is necessary for adequate cerebral perfusion in most patients. ## 2) CVP - Is the pressure in the vena cava at the point of blood returning to the right atrium and may reflect volume status - CVP values at the extremes usually reflect hypovolemia (less than 2 mmHg) and hypervolemia (greater than 18 mm Hg). ## Indicators of oxygen delivery ## 1) Lactic acid - Lactic acid is formed during anaerobic metabolism. - During states of hypoperfusion, the tissues receive less blood and therefore less oxygen. - If there is less oxygen for the tissues, they will use anaerobic metabolism, with the subsequent production of lactic acid. ## 2) Venous oxygen saturation - The oxyhemoglobin saturation of venous blood returning to the right atrium is normally 70%-75% (with a normal [99%-100%] arterial oxygen saturation), indicating that the normal oxygen extraction ratio is around 25%-30%. - In times of decreased oxygen delivery (caused by anemia, a decrease in Sao2, CO, or tissue perfusion), more oxygen is extracted from the blood that is being perfused to tissues, causing an increased extraction ratio and thus a decrease in venous oxygen saturation.