Introduction To Clinical Biochemistry & Blood Chemistry PDF

Introduction to Clinical Biochemistry & Blood Biochemistry 01/10/2024 (Tuesday Groups) 02/10/2024 (Wednesday Groups) 2 Clinical Biochemistry Clinical biochemistry is the extension of medicine in the laboratory, CB bases on both medicine and analytical chemistry methods...

Introduction to Clinical Biochemistry & Blood Biochemistry 01/10/2024 (Tuesday Groups) 02/10/2024 (Wednesday Groups) 2 Clinical Biochemistry Clinical biochemistry is the extension of medicine in the laboratory, CB bases on both medicine and analytical chemistry methods. 3 Clinical biochemistry is not only an analytical science but also an interpretative science, The analytical part involves the determination of the level of chemical/biochemical components in body fluids in the lab. 4 The interpretative part examines these results and uses them in the diagnosis of disease, the screening for susceptibility to a specific diseases, and the monitoring the patient progress in treatment. 5 Diagnosis A glucose level equal to or less than 100 mg/dL is accepted normal. A fasting glucose test of 126 mg/dL or above indicates the diabetes mellitus. 6 Screening PKU screening test is a blood test given to newborns 24–72 hours after birth. The blood phenylalanine concentration in newborns is normally 0.5 mg-1 mg/dL (30-60 μmol/L). Infants with PKU have phenylalanine value higher than 2 mg/dL (121 μmol/L). 7 Monitoring  Determination of HbA1c provides an important tool for monitoring the efficiency of dietary control and therapy during treatment of diabetes mellitus.  Among diabetic patients, HbA1c level greater than 9.0% indicates poor control of diabetes (Normal value less than 5.7%).  Poor control of diabetes is a risk factor for complications, including renal failure, blindness, and neurologic damage. 8 Biological specimen The material of Clinical Biochemistry is biological sample (specimen/biospecimen), It deals with measurement of all illness-associated chemicals in biological samples (blood, urine, cereprospinal fluid, etc.). 9 Clinical biochemistry uses chemical/biochemical/immun reactions to determine the levels of various chemical compounds. Several simple chemical reactions are used to detect and quantify different compounds in specimens. 10 Best biological sample? The best biological sample is the tissue where the change itself takes places. But the use of tissue is not possible for humanitarian and ethical reasons, Also, it is expensive, required complicated and invasive methods/devices (not repeatable). 11 Biological Samples A biologic sample is a biologic material to be analyzed by clinical biochemistry lab. It is a part of body or produced by body. Biological samples; Blood Urine Cerebrospinal fluid (CSF) 12 Other biological samples Semen/seminal fluid Stool Broncoalveolar lavage (BAL) Breast milk Pleural fluid Pericardial fluid Synovial fluid Cord blood Meconium  Advantages of blood samples 13 Blood is the most important and frequently used biological sample for medical purposes, Alterations in tissues rapidly change blood composition (contact with almost all tissues). It can be obtained by a minimally invasive intervention, Requires relatively easy skills, Cheap (an injector & a tube!). 14 Blood Blood is frequently considered a tissue located in circulation system, It circulates all tissues via pumping force of the heart. Therefore, it contacts with almost all tissues in the body. 15 There is an intense substance/fluid exchange between blood and tissues;  The sum of exchange processes determine the composition of the blood. 16 Components of the blood Blood consists of/carries the following to the body tissues (and from tissues). Cells (red cells, white cells..) Water & Electrolytes Nutrients (glucose, lipids, amino acids, vitamins, etc) Proteins (blood proteins & antibodies, enzymes) Hormones Gases (oxygen &carbon dioxide) 17 Organs that actively contribute to blood composition Small & large intestine Liver Lungs Kidneys 18 Leakage to the blood Many molecules located in the tissue may “leak” to the blood stream as a result of physiological cell death, The leakage increases when the tissue undergoes damage, An increase in the amount of a substance (or an enzyme activity) indicates tissue damage (disease). 19 ALT and AST enzymes in acute hepatitis  Normal levels for both enzyme; < 40 IU/L,  After a viral infection, liver cells (hepatocyes) are damaged,  There is a marked elevation typically >400 IU/L.  ALT; alanine transaminase  AST; aspartate transaminase  Alkaline Phosphatase (ALP) 20 enzyme ALP is often considered a liver enzyme because it is primarily found in the liver, However, it also exists bones, kidneys, intestines and other tissues, These tissues synthesize different ALP enzymes, Actually blood ALP levels represent total ALP activity. 21 The normal serum concentration of alkaline phosphatase (ALP) in adults over the age of 18 range from 37 to 116 U/L. ALP activity in an pregnant woman was 2817 U/L. ALP activities were 702 U/L and191 U/L after two and six weeks of postpartum, respectively. Because the placenta also contains a high amount of ALP isoenzyme. Case Reports inWomen's Health 27 (2020) e00214  How to distinguish placental enzyme? 22 Placental ALP is very heat stable enzyme whereas liver and bone isoenzymes are much less stable at elevated temperature,  Hence the effect of heat on the total enzyme activity can help to indicate which are the predominant isoenzymes. 23 Heat Fractination Heat serum sample at 56 C x 15 min, then compare with unheated sample. 24 ALP in children Traditionally, total serum ALP activity has also been used as a biochemical marker for bone formation. The changes in total serum ALP activity roughly reflect the changes in serum Bone-ALP (B- ALP) levels in healthy children. 25 26 Proteins in the blood Some proteins are produced by tissues (mostly by liver) and secreted into blood in which they play their roles, A decrease in the level of these proteins may indicate tissue damage (disease).  Blood albumin in hepatic chirrosis (Cirrhosis is a condition in which the liver is scarred and permanently 27 damaged) Albumin is an important component of blood, It is synthezied by the liver and secreted to the blood in which it has multiple functions, Whenever the liver lost their sythesize capacity due to chirrosis blood albumin levels may decrease to 1 g/dL (Normal levels; 3.5-5.5 g/dL).  Composition 28 Plasma; liquid part of blood, 55% Buffy coat; white blood cells (leukocytes) + platelets (trombocytes), 1% Red Blood Cells (erythrocytes), 44% 29 Erythrocyte count, Hemoglobin amount, Hct Erythrocytes form the large part of blood in terms of volume. There are correlations between erythrocyte count and Hct (Erythrocyte volume/Total volume, %), and Hb amount These cells have lost all their organelles in favor of hemoglobin. 30 Blood counter 31 Blood parameters have clinical importance; Indicates ANEMIA, a condition in Reduced erythrocyte which count erythrocyte Reduced Hemoglobin count and/or Hb amount are not amount enough for Reduced Hct oxygen transport. 32 Increased white blood cell count…Remarks the existence of infection. Reduced platelet count…Remarks a tendence to delayed coagulation (blood clotting) and bleeding. 33 Complete Blood Count (CBC) 34 Plasma vs. Serum   Plasma is the part of circulating 35 blood,  When blood is taken from body into a tube, it automatically gets clotted,  Fibrinogen turns into fibrin, a protein that creates a web-like protein structure,  This protein structure traps all blood cells and makes up a “blood clot”,  To prevent clotting an anticoagulant must be used. 36 Whole blood (contains anticoagulant) is used to measure; Blood cell counting HbA1c (monitoring diabetes) Plasma is mostly used to measure; Fibrinogen Other clotting factors (TT, PT, aPTT)  Serum is typically used for all clinical 37 biochemistry testing due to the ability to test a wide range of assays  Test Panels 38 Lab tests can be gathered as organ- based, metabolism-based or system- based panels; Renal Panel (Kidney function tests): Glucose, urea, creatinine, albumin, Ca, Na, K, Cl and bicarbonate. Liver Panel (Liver function tests): AST, ALT, ALP, Bilirubin, Albumin, Total Protein. 39 Panels Lipid Panel: Cholesterol, LDL-C, HDL-C and triglycerides. Tyroide Panel; TSH, Free T4 (thyroxine), Free T3 (triiodothyronine). Tumor Panel, Nutritional Panel... 40 Panels The composition of the panels may vary according to the capacity/practice of the laboratory. Some molecules (such as glucose) may be found in different panels.  Anticoagulants 41  Anticoagulants are used to inhibit blood coagulation.  Commonly used anticoagulants;  EDTA (Ethylene Diamine Tetra Acetic Acid)  Double oxalate (ammonium/potassium)  Sodium citrate  Heparin (binds to prothrombine) 42 Additive Some type of blood tubes contain additive such as sodium fluoride, Sodium floride an inhibitor of glycolysis and stops glucose utility by blood cells in the blood tube, For this reason, it is used for glucose measurement. 43 44 45 Urine Urine is produced by the kidneys and excreted through the urinary tract. Urine is a waste product composed of water and water soluble nitrogen products, electrolytes etc. 46 Urine Urine is often used as a diagnostic specimen for many disease conditions. Diagnosis based on both physical and chemical components, that may give insight to processes within the body, Urinalysis, a common clinical analysis of urine is used. 47 Urine is formed from blood, but is not simply a filtrate of blood, The secretion and reabsorption processes of the kidneys greatly alter the urine composition, Therefore, the compositon of urine reflect the capabilities and disoders of the kidney.  Physical Characteristics 48 Physical characteristics of urine include color, turbidity (transparency), smell (odor), pH (acidity) and density. Many of these characteristics are identifiable by visual examination, but some require laboratory testing. 49 Color  Typically yellow-amber, but varies according to recent diet and the concentration of the urine.  Drinking more water generally tends to reduce the concentration of urine, and therefore causes it to have a lighter color.  Dark urine may indicate dehydration.  Red urine indicates red blood cells within the urine, a sign of kidney damage and disease. 50 Smell The smell of urine may provide health information. Generally fresh urine has a mild smell but aged urine has a stronger odor similar to that of ammonia.  Acidity/pH 51 The pH of normal urine is generally in the range 4.6 – 8,0 with a typical average being around 6.0. Much of the variation occurs due to diet. For example, high protein diets result in more acidic urine, but vegetarian diets generally result in more alkaline urine (both within the typical range of 4.6 – 8.0). 52 Density Density is also known as “specific gravity”, This is the ratio of the weight of a volume of a substance compared with the weight of the same volume of distilled water, The density of normal urine ranges from 1.001 to 1.035.  Turbidity 53 The turbidity of the urine sample is evaluated subjectively and reported as clear, slightly cloudy, cloudy, opaque or flocculent. Normally, fresh urine is either clear or very slightly cloudy. 54 Turbidity Excess turbidity results from the presence of suspended particles in the urine, the cause of which can usually be determined by the results of the microscopic urine sediment examination. Common causes of abnormal turbidity include: increased cells, urinary tract infections or obstructions.  pH/Role of the Body 55 Results: The mean urine pH was;  6.15 for vegans, 5.90 for lacto-ovo vegetarians, and 5.74 for omnivores. Results point out the role of human body. The less protein intake, the less acid excretion. https://doi.org/10.1053/j.jrn.2008.04.007  Urine creatinine/Role of the 56 kidneys Urine creatinine (24-hour urine collection) values can range from 500 to 2000 mg/day (Results depend on the age and amount of lean body mass). Lower urine creatinine levels may indicate an existence of a renal disease. 57 Cerebrospinal fluid (CSF) Cerebrospinal fluid (CSF) samples are used for clinical laboratory analysis to look for conditions that affect the brain and spine. 58 CSF is the clear fluid that delivers nutrients to the central nervous system (CNS). In normal adults, the CSF volume is 90 to 200 mL. 59 Cerebrospinal fluid (CSF) analysis is a diagnostic tool for many conditions affecting the central nervous system. Urgent indications for lumbar puncture include suspected central nervous system infection or subarachnoid hemorrhage. 62 Subarachnoid hemorrhage has a high mortality rate, and rapid diagnosis is key to improve outcomes. Computed tomography of the head is nearly 100% sensitive for subarachnoid hemorrhage in the first six hours after symptom onset, but CSF analysis may be required if there is a delay in presentation or if imaging findings are equivocal. 63 Xanthochromia and an elevated red blood cell count are characteristic CSF findings in patients with subarachnoid hemorrhage. 65 Clinical Biochemistry Laboratory techniques  Spectrophotometry  Fluorimetry  Atomic Emission and Absorption  Ion Selective Electrodes  Oxygen and Carbon Dioxide Electrode  Gas Chromatography  High Performance Liquid Chromatography  Electrophoresis  Molecular Diagnostics  Immunological and Radioisotope Techniques 66 67 68 Each of the test is measured by a different chemical reaction  Dye; o-Dianisidine  Reduced dye; colorless  Oxidized dye; colored