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Clinical Chemistry
QUALITY CONTROL
TERMS TO REMEMBER:
- Quality: a feature/characteristic of a product which meets the expected criteria of a consumer (customer).
- Control: a solution that resembles a human sample that is used for QC purposes only
- Standard: a colorless solution with known concentration of substances used for calibration
- Specificity: defined as the ability of a method to measure the analyte of interest ONLY.
- Sensitivity: defined as the ability of a method to measure analytes even at its lowest concentration
- Accuracy: nearness of measured value to that of the target value
- Precision: nearness of measured values to each other
- Diagnostic specificity: defined as the ability of a method to detect a population of individuals absent of a disease process
- Diagnostic sensitivity: defined as the ability of a method to detect a population of individuals having the presence of disease
- Intralab QC (internal QC): control samples are run simultaneously with a patient to ensure reliability of methods and result. Used for daily monitoring of accuracy and precision of method used. Detects random and systematic errors.
- Interlab QC (external QC): laboratories are given samples with unknown concentrations for them to test and results are compared with other laboratories thus maintaining “long-term accuracy” to methods utilized. o Results difference of greater than 2SD indicates disagreement with other lab included.
- Mean: average of a set of values ( mean = Σx/n ). Measures central tendency.
- Median: midpoint of a set of values
- Mode: the most frequent among all values/data
- Range: Simplest expression of spread or distribution
- Standard Deviation: it is defined as the measure of dispersion of values to that of the mean. Most frequent used measure of variation.
o 𝑆𝐷 = √𝚺(𝐱−𝐦𝐞𝐚𝐧)
2 𝑛−
- Coefficient of variation: mean expression in percentile. Index of precision o 𝑪𝑽 = (^) 𝒎𝒆𝒂𝒏𝑺𝑫 𝒙 𝟏𝟎𝟎
- Variance: square of SD. V=SD^2
- T-test: this is used to assess if there is a statistical difference between the means of 2 groups of data
- F-test: this is used to assess if there is a statistical difference between the SD of 2 groups of data
- Shewhart Levey-Jennings Chart: most widely used QC chart
- Trend: six or more consecutive values that either increase or decrease gradually (will cross the mean) – main cause: reagent deterioration
- Shift: six or more consecutive values that are distributed on one side or other side of the mean (does NOT cross the mean) – main cause: improper instrument calibration
WESTGARD RULES TYPE OF ERROR RULES SOURCES OF ERROR RANDOM
(^1) 2s (warning rule), 13s and R4s
By chance errors: mislabeling, pipetting error, fluctuations in temperature & voltage SYSTEMATIC
(^2) 2s, 41s and 10x
Improper calibration, reagent deterioration, contaminated solutions, instability of both samples and solutions
- Delta check: used to check if there are significant differences between present set of values to that of past values on the sample of same individual.
- Six Sigma: a way of improving product processing to eliminate defects
INSTRUMENTATION
DEFINITION OF TERMS:
- Energy: entity that this transmitted by electromagnetic waves
- Wavelength: defined as the distance between two successive peaks
- Nanometer: unit expression of wavelength
- Frequency: number of waves that passes a point of observation per one unit of time
SPECTROPHOTOMETRY
- Measures transmitted light in a colored solution
- Measurement is based upon Beer-Lambert-Bouguer Law (Beer’s Law/Beer- Lambert’s Law)
BEER-LAMBERT LAW
- States that concentration of an unknown analyte is directly proportional to the light absorbed and inversely proportional to light transmitted. ✓ Absorbance is proportional to the inverse log of transmittance
SINGLE-BEAM SPECTROPHOTOMETER
Photo reference: Henry’s Clinical Diagnosis and Management by Laboratory Methods, 22nd^ edition DOUBLE-BEAM SPECTROPHOTOMETER
- Double- beam in time – 1 photodetector
- Double-beam in space – 2 photodetectors (1- sample beam, 2- reference beam) **PARTS OF SPECTROPHOTOMETER
- LIGHT SOURCE** ✓ Tungsten: for visible and near infrared region ✓ Deuterium: for UV region ✓ Xenon discharge lamp: for UV and Visible region 2. ENTRANCE SLIT – minimizes the entry of stray light to the monochromator 3. MONOCHROMATOR – isolates specific wavelength ✓ Prisms: light is refracted
POTENTIOMETRY
- Measures electric potential
- pH electrode – glass electrode
- pCO 2 electrode
- ion – selective electrode ✓ Sodium: glass electrode ✓ Potassium: Valinomycin gel ✓ Chloride: Tri-N-octyl propyl ammonium chloride decanol
ELECTROPHORESIS
- Separation of proteins is aided by an electric current IONS POLE POSITIVE CATIONS CATHODE NEGATIVE ANIONS ANODE
- pH of buffer: 8.
- support materials: ✓ Agarose gel - separation by electric charges ✓ Cellulose acetate – separation by molecular size ✓ Polyacrylamide gel – separation by charge and molecular size
ELECTROPHORETIC PATTERN OF CERTAIN CONDITIONS Alpha 1 -globulin flat curve Juvenile cirrhosis Alpha 2 -globulin band spike Nephrotic syndrome Beta-gamma bridging Hepatic cirrhosis Monoclonal gammopathy (gamma spike) Multiple myeloma Polyclonal gammopathy Rheumatoid arthritis and malignancy Small spike in Beta-region Iron deficiency anemia
CARBOHYDRATES
- Composed of carbon, hydrogen and oxygen
- Are water soluble
- Are important source of energy for the body’s mechanisms
- Classifications: ✓ Monosaccharides: Glucose, fructose and galactose ✓ Disaccharides: maltose (glucose + glucose), lactose (galactose + glucose) and sucrose (fructose + glucose; most common non reducing sugar) ✓ Polysaccharides: starch and glycogen
GLUCOSE
- Primary sugar found circulating in the body
- Carbohydrate metabolism: ✓ Glycolysis : glucose → lactate or pyruvate → energy (↑ glucose) ✓ Glycogenolysis : breakdown of glycogen to glucose (↑ glucose) ✓ Glycogenesis: formation of glycogen from sugars for storage (↓glucose) ✓ Gluconeogenesis: formation of glucose from non-carbohydrate sources (↓ glucose)
- Hormones for glucose regulation ✓ Hypoglycemic o Insulin – released by β cells of islet of Langerhans o Entry of glucose in the cell o Falsely low measurement of serum insulin is seen in the presence of hemolysis. ✓ Hyperglycemic o Glucagon – released by α cells of islet of Langerhans o Primary hormone that increases glucose concentration. o NV in fasting plasma: 25-50pg/mL o Somatostatin – released by delta cells of islet of Langerhans
o Inhibits the action on inulin, GH and glucagon. o Cortisol o Epinephrine o Growth hormone o Thyroxine o ACTH
- MUST KNOW FOR SPECIMEN FOR GLUCOSE DETERMINATION ✓ FBS should be obtained from an 8-10 hours fasting sample ✓ In terms of glucose levels: capillary > venous but < arterial ✓ Glucose is metabolized at: o Room temperature: 7 mg/dL/hr o 4°C: 2 mg/dL/hr ✓ Tube of choice: Gray top (anticoagulant: _____________; anti-glycolytic agent: _____________)
GLUCOSE DETERMINATION
METHOD PRINCIPLE REAGENTS END PRODUCT/ COLOR REACTION i. CHEMICAL METHOD A. OXIDATION REDUCTION METHOD
1. ALKALINE COPPER REDUCTION METHOD Folin-Wu
- Modification: Benedict’s Test
Copper Reduction Alk. Copper reagent Phosphomolybdic Acid
Molybdenum – BLUE
Nelson- Somogyi Copper Reduction Alk. Copper reagent Arsenomolybdic
Molybdenum – BLUE
acid
Neocuproine Copper Reduction Cuprous ions Neocuproine
Cuprous- Neocuproine Complex – YELLOW/ YELLOW ORANGE
2. ALKALINE FERRIC REDUCTION METHOD Autoanalyzer (Hagedorn-Jensen)
Ferricyanide reduction (Inverse Colorimetry)
K 3 Fe(CN) 6 K 3 Fe(CN) 6 -
B. Condensation Method Ortho-Toluidine Dubowski reaction; Condensation Method
O-toluidine Glacial Acetic Acid
Glycosylamine
II. ENZYMATIC METHODS Glucose Oxidase
- Saifer Gernstenfield
- Clarke electrode
Enzymatic
- Colorimetric
- Polarographic
Glucose Oxidase Peroxidase O-dianisidine
Oxidized o- dianisidine – ORANGE BROWN
Hexokinase (REFERENCE METHOD)
Enzymatic Hexokinase G6PD
NADPH+
LABORATORY TESTS
- Screening Tests ✓ Fasting Blood Sugar – 8-10 hours fasting
LIPIDS AND LIPOPROTEINS
- Lipids are more commonly referred to as fats
- Insoluble in water but soluble in organic solvents
- Major forms of lipids: ✓ FATTY ACIDS o Simplest o Building blocks of lipids o Saturated (no double bonds) or unsaturated (with double bonds) ✓ TRIGLYCERIDES o Tri – three molecules of fatty acids + one molecule of glycerol o Breakdown is facilitated by lipoprotein lipase o Primary cause of turbid serum o Main storage form of lipid o Requires a fasting specimen (12-14 hours) o > 500mg/dL highg risk for CAD o RV: <500 mg/dL - normal 150-199 mg/dL - borderline high 200-499 mg/dL - high TAG >500 mg/Dl - very high TAG (acute / recurrent pancreatitis) ✓ CHOLESTEROL o Not readily catabolized = not a source of fuel o No fasting is required o Four ringed structure made by hepatocytes o Constituent of cell membranes and precursor of some hormones (steroids: progestin, glucocorticoids, mineralocorticoids, androgen and estrogen). o Estrogen promotes transport and excretion of CHOLE o Should be measured in adults ≥ 20 y/o at least once every 5years.
o RV: <200 mg/dL = desirable
200 – 239 mg/dL = borderline high
≥ 240 = high cholesterol
o Two forms: esterified (60-70%) and free cholesterol (30-40%) o TAG and Chole most important lipids in management of CAD ✓ PHOSPHOLIPIDS o Structure: 2 fatty acids + phospholipid attached to glycerol o Most abundant lipid o Can also be found as surfactants in lungs. Def in neonates: RDS o Forms: Lecithin/phosphatidylcholine (major, 70-75%), sphingomyelin (18-20%), phosphatidylserine and phosphatidylethanolamine (3-6%) and lysophosphatidylcholine (4-9%) o RV: 150 – 380 mg/dL (serum) o Sphingomyelin o Component of cell membranes (RBC and nerve sheath) o Niemann-pick dxs: accumulation in the liver and spleen. (lipid storage disorder) ✓ LIPOPROTEINS o Carrier proteins for lipids o Major lipoproteins A. Chylomicrons : largest and least dense. ▪ Contains mostly TAG. ▪ Produced in the intestines. B. VLDL/Pre-beta lipoprotein. Made in the liver. C. HDL/ Alpha Lipoprotein: smallest but most dense lipoprotein. ▪ Removes excess cholesterol from cells. ▪ Produced by liver and intestine. ▪ Maintains balance of cholesterol.
▪ CDC Reference method for determination: ultracentrifugation, precipitation with heparin-MnCl 2 and Abell-Kendal assay. D. LDL/Beta Lipoprotein: Marker of CHD risk. ▪ most cholesterol-rich and most atherogenic. ▪ major end-product of VLDL catabolism.
HDL LDL VLDL Chylomicrons Good cholesterol
Bad cholesterol Carrier of endogenous TAG
Carrier of exogenous TAG
Migration Alpha Beta Pre-beta Origin Size 70-100 100-300 2000 > 2000 Density 1.063-1. (bottom layer)
1.019-1.063 0.95-1.006 < 0.95 (top layer) Protein 50% 20% 4-8% 1-2% LIPID CONTENT (%) Free cholesterol 3-5 6-8 4-8 1- Esterified 15-20 45-50 16-22 2- TAG 2-7 4-8 45-65 80- Phospholipid 26-32 18-24 15-20 3- Lipid: protein ratio
Apolipoproteins A-1, A-II, C B-100, E B-100, A-1, C, E A1, B-48, C, E o Minor lipoproteins: A. IDL – Subclass ▪ Migrates either in the pre-beta or beta region ▪ Major apolipoprotein: Apo B- B. Lp(a) aka sinking pre-beta, linked to atherosclerosis o Abnormal lipoproteins: LpX – linked to obstructive jaundice, β-VLDL aka floating β lipoprotein
- Indicator of cholestasis. o Beta-VLDL: floating beta lipoprotein
- Migrates with LDL in beta region found in type 3 hyperlipoproteinemia or dysbetalipoproteinemia.
- VLDL rich in cholesterol
APOLIPOPROTEINS
- Apo A – major protein component of HDL ✓ Apo A-I: LCAT activator ✓ Apo A-II: may inhibit hepatic & lipoprotein lipases; increases plasma TAG
- Apo B – major protein component of LDL ✓ Apo B-48: found in chylomicron ✓ Apo B-100: synthesized in liver; found in VLDL & LDL
- Apo C – major protein component of VLDL ; minor in HDL and LDL ✓ Apo C-I: may inhibit the hepatic uptake of VLDL and cholesterol ester transfer protein ✓ Apo C-II: if deficient – there would be reduced clearance of TAG-rich lipoproteins ✓ Apo C-III: main form found in HDL. Lipolysis of TAG-rich lipoproteins is inhibited by this form
- Minor apolipoproteins ✓ Apo D: aids in the activation of LCAT ✓ Apo E: Arginine rich o Apo E-I o Apo E-II: associated with type III hyperlipoproteinemia o Apo E-III: most common isoform o Apo E-IV: associated with high levels of LDL, increased risk for Alzheimer’s and CHD
FREDERICKSON AND LEVY’S CLASSIFICATION OF HYPERLIPOPROTEINEMIA
TYPES STANDING PLASMA TEST* GEL ELECTROPHORESIS
TYPE I Creamy layer – Clear plasma Normal TYPE IIa Negative – Clear plasma Increased β band TYPE IIb Negative – Cloudy plasma Increased β and pre- β band TYPE III Occasional – Cloudy plasma Increased pre- β band (broad β band) TYPE IV Negative – Cloudy plasma Increased α2 band TYPE V Creamy layer – Cloudy plasma Increased α2 band ***** plasma is placed in a test tube and stored at 4°C overnight. Presence of “cream” floating and turbidity of plasma is observed for presence of chylomicron and VLDL respectively
LIPID STORAGE DISEASES Fabry’s disease alpha galactosidase deficiency Gaucher beta galactosidase deficiency Krabbe cereboside beta galactosidase deficiency Metachromatic Leukodystrophy arylsufatase A deficiency Niemann Pick sphingomyelinase deficiency Sandhoff hexosaminidase A and B deficiency Tay Sach hexosaminidase A deficiency
LIPID PROFILE
Desirable Borderline High High
Triglycerides <150 mg/dL 150-199 mg/dL 200-499 mg/dL HDL-C 40 mg/dL n/a n/a LDL-C <130 mg/dL 130-159 mg/dL 160-189 mg/dL Total Cholesterol <200 mg/dL 200-239 mg/dL >240 mg/dL
STRATIFIED RISK FACTORS FOR CHD
Age (in years) Moderate Risk (mg/dL) High Risk (mg/dL) 2-19 >170 > 20-29 >200 > 30-39 >220 > 40- above >240 >
WRITE THE FRIEDEWALD AND DELONG’S FORMULA
PROTEINS
- Composed of carbon, hydrogen, oxygen and nitrogen
- Most abundant macromolecule in the body
- Amphoteric in nature
- Synthesized in the liver except for immunoglobulins (which are synthesized by plasma cells)
- In alkaline Ph = proteins are negatively charged
- In acidic pH = proteins are positively charged
- Structures: ✓ Primary: amino acid sequence ✓ Secondary: conformations could either be alpha-helix, beta-pleated, sheath and bend form ✓ Tertiary: actual 3D configuration ✓ Quaternary: protein already consists of 2 or more polypeptide chains
PLASMA PROTEINS
FRACTIONS SPECIFIC PROTEINS Prealbumin Aka transthyretin Marker for malnutrition 2nd most predominant protein in the CSF Transfer T4 and retinol (Vitamin A) ↑ Alcoholism, Chronic renal failure, steroid txm. ↓ poor nutrition RV: 18 – 45 mg/ dL Albumin Most abundant protein Acts as a transport protein Negative acute phase reactant Maintains osmotic pressure Elevated in Cystic fibrosis
Negative acute phase reactant Low level: nephrotic syndrome Analbuminemia: albumin absence Bisalbuminemia: there are 2 bands seen in the albumin region Hypoalbuminemia: low levels of albumin RV: 3.5 – 5.0 g/dL GLOBULIN Measurement: TP – A = G ↑ Early cirrhosis RV: 2.3 – 3.5 g/dL Alpha 1 globulin Alpha 1 antitrypsin (AAT) Acute phase reactant. Released from WBC to combat inf Protease inhibitor NV 2.3-3.5 mg/dL AFP Tumor marker for hepatocellular carcinoma (hepatic and gonodal cancer). Increased in presence of twins and neural tube defect. Decreased in down syndrome. Screening for maternal AFP for NTD and DS: 15 and 20 weeks of gestational age. RV: 5 ng/ml both in adults and children Alpha-1-acid-glycoprotein (orosomucoid) Carrier proteins for steroid hormones (Progesterone). Increased in neonatal bacterial inf. RV: 55-140 mg/dL Alpha 1 -antichymotrypsin Inhibits serine Proteinases Acute phase reactant. Binds and inactivates PSA Associated with Alzheimer’s dxs, ↓ in liver dxs RV: 30 – 60 mg/dL Gc-globulin
✓ Regulates actin and myosin ✓ Marker for acute coronary syndrome ✓ Most important marker for AMI ✓ RV: <0.1 ng/mL
- BNP ✓ ↑ ventricular systolic and diastolic dysfunction ✓ Congestive heart failure
- Cystatin C ✓ Marker for kidney function (GFR) ✓ Endogenous renal marker
- Beta-trace protein ✓ Marker for CSF leakage
- Amyloid ✓ Fibrous protein aggregates
- Bence-Jones protein: protein found in patients with Multiple Myeloma ✓ Unique feature: Coagulates at 40-60°C and dissolves at 100°C ✓ Method for measurement: Immunofixation ✓ Electrophoretic pattern: “tall spike” or “monoclonal peak”
METHODS FOR ALBUMIN QUANTITATION
- Electrophoresis
- Biuret Method ✓ Principle: measurement of at least 2 peptide bonds and formation of a violet colored chelate. ✓ Measured at 540nm ✓ Reagents: Rochelle salt (NaK tartrate), Alkaline CuSO 4 , NaOH and KI
- Kjeldahl Method ✓ Reference method
✓ Based upon the digestion of protein and measurement of nitrogen content of proteins ✓ Albumin nitrogen x 6.25 = albumin
- Lowry (Folin-Ciocalteu) method ✓ Reagent: Phosphotungstomolybdic acid
- Dye-binding method ✓ BCG: most commonly used ✓ BCP: most sensitive, specific and precise ✓ H-ABA: with salicylates and bilirubin interferences
CSF OLIGOCLONAL BANDING
- Multiple sclerosis: 2 or more IgG bands in the gamma region
- Other dxs with two more bands in the CSF: Encephalitis, neurosyphilis, Gullain- Barre syndrome, neoplastic dxs
- Serum banding in CSF: Leukemia, lymphoma and viral inf.
AMINOACIDOPATHIES
- Alkaptonuria ✓ Absence of homogentisate oxidase in tyrosine pathway ✓ Ochronosis: tissue pigmentation ✓ Darkening of urine upon standing
- Homocystinuria ✓ Impaired activity of cystathionine B-synthetase ✓ Elevated homocysteine and methionine in blood and urine ✓ Screening test: Modified Guthrie Test (L-methionine sulfoximine)
- MSUD ✓ Reduced or absence of a-ketoacid decarboxylase ✓ Accumulation of leucine, isoleucine and valine. ✓ Screening test: Modified Guthrie Test (4-azaleucine)
- Phenylketonuria ✓ Def of phenylalanie hydrolase ✓ Phenylpyruvic acid in both blood and urine ✓ Musty odor urine ✓ Screening: Guthrie Bacterial Inhibition Assay ( Bacillus subtillis)
- Tyrosinemia ✓ Def. of either of these enzymes tyrosine aminotransferase, 4- hydroxyphenylpyruvic acid oxidase, fumarylacetoacetate ✓ Increased levels of methionine and p-hydroxyphenolpyruvic acid in blood. ✓ Results to liver damage or cirrhosis
NON – PROTEIN NITROGEN
- Monitor and asses renal function.
- Result from the breakdown of protein and nucleic acids.
UREA
- Most abundant (45-50%) NPN
- Major end product of protein metabolism
- First metabolite to increase in kidney dxs
- BUN:Crea Ratio 10:1-20:
- Urea is decreased in severe hepatic dxs
- Methods: ✓ Micro-Kjeldahl Nesslerization method o Indirect method o Nitrogen x 2.14 = urea x 0.467 = BUN ✓ Rosenthal method o Direct method o Diacetyl monoxime method ✓ Enzymatic method o Urease ✓ IDMS o Reference method
CREATININE
- Major end product of muscle catabolism
- Produced by three AA: methionine, arginine and lysine
- Index of overall renal function
- Evauluate fetal kidney maturity
- 100% is excreted
LIVER FUNCTION TEST
Photo reference: Henry’s Clinical Diagnosis and Management by Laboratory Methods, 22nd edition
METHODS
- Van den Bergh: color reaction for bilirubin ✓ Color reagent: Diazo reagent ✓ Product: Azobilirubin ✓ Evelyn-Malloy o Medium: ACID o Dissociating agent: 50% methanol o End color: red/reddish purple ✓ Jendrassik-Grof o Medium: ALKALINE o Dissociating agent: Caffeine sodium benzoate o End color: blue
- Icterus index ✓ Applicable to newborn and neonates
- Bromsulfonpthalein Dye Excretion test ✓ Rosenthal White o Double collection method o Collection is done after 5 mins and 30 mins o Reference values: 50 % dye retention (5mins) 0% (30mins) ✓ Mac Donald o Single collection method o Collection: done after 45 mins (+ 5% dye retention)
DISEASES
- Gilbert syndrome: defect in transport protein in liver
- Crigler-Najjar syndrome: defective conjugation due to deficiency of UDP-GTase
- Dubin-Johnson syndrome: defective excretion due to blockage by stones
ENZYMES
DEFINITION OF TERMS
- Apoenzyme: protein portion of enzyme without cofactor
- Holoenzyme: complete active enzyme
- Active site: site where enzymatic reaction occurs
- Allosteric site: site other than the active site
- Isoenzyme: forms of enzyme that are different from each other but still catalyzes same reaction
CATEGORIES
1. Oxidoreductase ✓ For oxidation/reduction reactions ✓ Ex: LDH, G6PD and Malate dehydrogenase 2. Transferase ✓ Catalyzes transfer of groups from one substrate unto another ✓ Ex: AST, ALT, CK, GGT 3. Hydrolase ✓ Hydrolysis ✓ Ex: ACP, ALP, 5’NT, AMS, LPS, CHS 4. Lyase ✓ Removal of groups but with no hydrolysis ✓ Ex: Aldolase 5. Isomerase ✓ Interconversion of isomers 6. Ligase ✓ Joins to 2 substrate molecules ✓ Ex: synthases
ENZYME METHODS SUBSTRATES FACTS
HEPATIC ENZYME PROFILE
ALP
Liver Kidney Bone Placenta Intestine WBC
Bodansky Shenowara Jones King-Armstrong Bessy Lowry-Brock
Β-glyceroPO 4 Β-glyceroPO 4 p-nitrophenylPO 4 p-nitrophenylPO 4
Optimum pH: 10 Greatly elevated in Paget’s disease Avoid using EDTA-Citrate- Oxalate
ALT (SGPT)
Liver RBCs
Reitman-Frankel (DNPH) Alanine α-keto Liver-specific Marked elevation with viral hepatitis De ritis ratio:
1 = viral; <1 = non-viral LD All tissues
Wacker Method (forward) Wrobleuski La Due (reverse) Wrobleuski Cabaud Berger Broida
NAD+ (cofactor) LD4 and LD Storage: 25°C up to 24 hours
GGT
Canaliculi of hepatic cells, Kidney, Prostate and Pancreas
SZAZ Gammaglutamyl p- nitroanilide
Most sensitive marker for alcoholic hepatitis
ChE Pseudo- Michael; Ellman
Acetylcholine ChE: CNS, RBC, Lungs, Spleen Pseudo: Liver – Succinylcholine (relaxant);
Tartrate
PSA Most useful for tumor marker for prostate cancer
RR: 0-4ng/mL
ACUTE MYOCARDIAL INFARCTION MARKERS (Bishop, Rodriguez, Coderes) Marker Onset (hours) Peak (hours) Duration (hours) Myoglobin 1-3 5-12 18- Trop I 3-4 10-24 7days up to 10-14days Trop T 3-6 12-18 5-10 days CK-MB 4-6 12-24 48- AST 6-8 24 5 days LDH 12-24 48-72 10-14 days
ELECTROLYTES
ELECTRONEUTRALITY
Na+^ + K+^ + 7 = Cl-^ + HCO 3 -^ + 25
ANION GAP: difference between unmeasured anions and unmeasured cations
AG = Na+^ - (Cl-^ + HCO 3 - ) AG = Na+^ + K+) - (Cl-^ + HCO 3 - )
Ref. range: 7-16 mmol/L Ref. range: 10-20 mmol/L
ELECTROLYTES INFORMATION
Sodium Most abundant cation in the ECF Has the greatest influence in serum osmolality Aldosterone : responsible for the reabsorption in tubules Atrial natriuretic factor: blocks secretion of both aldosterone & renin Hyponatremia is the most common electrolyte disorder ~ for every 100mg/dL increase in blood glucose, there is a decrease by 1.6 mmol/L of serum sodium Hypernatremia Hyponatremia Excessive water loss Increase water retention Water intake is decreased Water imbalance Increase Na+ intake/retention Sodium loss Methods: Flame Emission Photometry (FEP) - yellow ISE – glass aluminum silicate AAS Colorimetry - Albanese Lein Potassium Major intracellular cation Regulates ICF volume regulation and H+ concentration, contraction of the heart and excitability of mucles Hyperkalemia Hypokalemia
Extracellular shift Renal loss Increased intake GI loss Renal excretion is decreaed Intracellular shift Artifactual (eg. Hemolysis, thrombocytosis)
Intake is decreased
Methods: FEP – violet ISE – valinomycin gel AAS Colorimetry – Lockhead and Purcell Chloride Major extracellular anion Only anion that serves as an enzyme activator Sweat chloride: diagnosis for cystic fibrosis Hyperchloremia Hypochloremia GI loss Hyperparathyroidism Diabetic ketoacidosis Low reabsorption of HCO 3 Low Na+ levels Mineralocorticoid excess & deficiency Methods: Mercurimetric method: Schales and Schales (indicator: diphenylcarbazone) Coulometric amperometric titration: Cotlove chloridometer Colorimetry ISE – electrodes with AgCl membranes Calcium Ion that is the most abundant in the body 3 rd^ most abundant in blood 99% (bone) and 1% (blood) PTH: promotes bone resorption Calcitonin: promotes bone deposition Vitamin D3: promotes intestinal absorption of calcium Methods:
