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Diagnostic Blood Tests and their meaning

PHM142 Fall 2013 Instructor: Dr. Jeffrey Henderson. Diagnostic Blood Tests and their meaning. Menglei (Christina) Xi, Jason Chou, Jonas Mak , David Hiebert PHM142 Metabolic Biochemistry & Immunology Wednesday 18 September 2013.

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Diagnostic Blood Tests and their meaning

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  1. PHM142 Fall 2013 Instructor: Dr. Jeffrey Henderson Diagnostic Blood Testsand their meaning Menglei (Christina) Xi, Jason Chou, Jonas Mak, David Hiebert PHM142 Metabolic Biochemistry & Immunology Wednesday 18 September 2013

  2. Example of Primary CareDiagnostic Test Requisition Form

  3. Full Blood Count

  4. Full Blood Count (FBC) • Simple blood test • Measures the following:

  5. Full Blood Count (FBC)

  6. Full Blood Count (FBC) • White Blood Cell Count • Determines if there might be an infection • Red Blood Cell Count • Determines if the body is receiving enough oxygen • Hemoglobin • Good measure for body’s ability to carry oxygen • Hematocrit • This test measures the amount of volume red blood cells take up in the blood.

  7. Full Blood Count (FBC) • MCV (Mean Corpuscular Volume) • The MCV shows the size of the red blood cells. • MCH (Mean Corpuscular Hemoglobin) • The MCH value is the amount of hemoglobin in an average red blood cell.

  8. Full Blood Count (FBC) • MCHC (Mean Corpuscular Hemoglobin Concentration) • Measures the concentration of hemoglobin in an average red blood cell. • RDW (Red Blood Cell Distribution Width) - Shows if the cells are all the same or different sizes or shapes.

  9. Full Blood Count (FBC) • Platelet Count • Determines of clotting is adequate • MPV (Mean Platelet Volume) - Measures the average amount (volume) of platelets.

  10. Cholesterol Testing Involves: Lipid profiles and target levels In comparison to other blood tests: Different target values depend on patient’s risk factors

  11. Why are blood cholesterol levels measured? • Cholesterol • Is an essential fat • Provides support in our cell membranes • Adds fluidity to the lipid bilayer • An essential component of steroid hormones • A build up of cholesterol in your arteries increases your risk of conditions such as heart disease

  12. Lipid Profile • This blood test gives • important information about amounts and types of fat in the bloodstream • Composed of different cholesterol tests • Bad cholesterol (LDL) • Good cholesterol (HDL) • Triglycerides (TG) • Total cholesterol • The concentrations are measured in mmol/L

  13. With too much Cholesterol (C) and Triglycerides (TG) • Excess settles on the inside of blood vessels • Plaques develop from fatty deposits • Leads to cardiovascular problems • Excess TG increase blood clots and the risk of heart attack and stroke

  14. Lipoproteinsare carrier molecules • Low Density Lipoprotein (LDL) • Less dense molecule with outer rim of lipoprotein surrounding cholesterol center • High Density Lipoprotein (HDL) • Smaller and more dense • Highest proportion of protein to cholesterol

  15. Triglycerides (TG) • Are esters derived from glycerol and 3 fatty acids An unsaturated triglyceride • They come from fatty food that you eat • Stored in fatty tissue & used for energy

  16. Why do blood cholesterol (C) and triglyceride (TG) levels go up? • Sources of cholesterol • Liver (80%) • Diet • Genetic predisposition • Types and amounts of fat consumed affect levels of “good” HDL or “bad” LDL levels • High triglyceride levels associated with • Drinking too much alcohol • Being overweight • Poorly controlled diabetes

  17. How Blood Cholesterol test results are interpreted • Health Care professionals calculate high, moderate, or low risk of cardiovascular disease (heart disease or stroke) within the next 10 years. • These are based on Risk Factors: • Your body mass index (BMI) • Having hypertension, diabetes, etc. • Your age, sex (M > 40, F>50) and family history. • Cholesterol profile

  18. Model for estimating 10 year risk of coronary artery disease involves: • Your age • Total Cholesterol • Smoking • HDL values • Genest, J., et al. 2003 Recommendations for the management of dyslipidemia and the prevention of cardiovascular disease: 2003 update. CMAJ. Oct 28, 2003; 169 (9) Online 1-10

  19. Target Lipid Levels • Based on risk categories set out in guidelines Genest, J., et al. 2003 Recommendations for the management of dyslipidemia and the prevention of cardiovascular disease: 2003 update. CMAJ. Oct 28, 2003; 169 (9) Online 1-10.

  20. Example ofHow Blood Cholesterol test results are interpreted • Patients with high risk of cardiovascular disease: • LDL-C target level < 2.5 mmol/L • HDL-C > 1.29 mmol/L • TG < 1.71 mmol/L • Total C : HDL ratio < 4 • Treatment regimen: Diet (lifestyle, reduced calories) and/or Medication(statins first line therapy)

  21. Glycosylated Hemoglobin Levels Synonymous with “glycohemoglobin”, “HbA1c”, “glycated hemoglobin”, etc.

  22. What is HbA1c? • HbA1c = Hemoglobins irreversibly bound to glucose(1) • Forms when in constant contact with glucose, basic thermodynamic properties of equilibrium • HbA0 + glucose Schiff base (R2C=N-R) HbA1c • High glucose concentrations shift equilibrium to form more Schiff base compounds, which encourages HbA1c formation (2)

  23. Why measure HbA1c? • Hemoglobins exist as functional groups on red blood cells • Red blood cells live for 3 months on average • Relatively high HbA1c levelsresults from relatively high average [blood glucose]for the past 3 months (3)(4)

  24. Targets of the HbA1c test • Diabetics diagnosed with Type 2 diabetes (3) • Individuals at high risk of contracting Type 2 diabetes, based on any combination of factors including: • Bodily lipid content • Inactivity • Abnormal cholesterol levels • High levels of triglycerides

  25. What’s normal? Measurement of proportion of HbA1c to total hemoglobin count (5)(6) • Generally, 4% - 5.7% HbA1c = normal • 5.7% - 6.4%HbA1c = at risk • If not currently diabetic, above 6.5%= abnormal • Will likely be diagnosed as diabetic • If currently diabetic, above 7%= abnormal • Improper management of blood glucose levels • Reconsider regime

  26. Creatine Kinase

  27. Creatine Kinase (CK) Enzyme catalysing Creatine and ATP to Phosphocreatine (PCr) and ADP Found in high energy tissues such as muscle or the brain http://upload.wikimedia.org/wikipedia/commons/c/c0/Creatine_kinase_rxn.png

  28. Why test for Creatine Kinase? Primarily to help diagnose myocardiac problems Various tests to determine CK levels in blood High levels indicates muscle damage, typically myocardial infarction or rhabdomyolysis Low levels are indicative of rheumatoid arthritis or alcoholic liver disease Patient type Lower limit Upper limit Unit Male 24, 60 174, 320 U/L or ng/mL 0.42 1.5 µkat/L Female 24, 96 140, 200 U/L or ng/mL 0.17[51] 1.17[51] µkat/L http://en.wikipedia.org/wiki/Reference_ranges_for_blood_tests

  29. How is Creatine Kinase tested? Blood serum or plasma can be used to test for CK Enzymatic activity is tested for using enzymatic activity assays such as electrophoresis assays Newer assays based on monoclonal antibodies are becoming popular

  30. Pros Extensive database from over four decades of clinical use Good preliminary test Cons Poor sensitivity outside a certain window( <6 hours and > 48 hours) Lack of specificity on where CK is found Overall, less than 5% of tests are false positive

  31. Summary • A Full Blood Count (FBC) is done to diagnose overall health of the cell components of blood • Based on results of the FBC, further testing may be requested. • In comparison to other blood tests, cholesterol testing involves hitting blood target levels which depend on the patient’s risk factors. • The 2003 Guidelines, for a high risk patient, set the target lipid levels for LDL-C at < 2.5 mmol/L and the Total C to HLD-C ratio at < 4. • HbA1c is a common test of long-term blood glucose concentration in diabetics or those at risk. • HbA0 + glucose Schiff base (R2C=N-R) HbA1c • HbA1c levels result from irreversibly bonded glucose-hemoglobin molecules. • Patients are considered diabetic when HbA1c > 6.5% • Creatine Kinase is an enzyme used to catalyze Pcr and ADP. High levels of this enzyme is usually indicative of myocardial infraction which can be determined with further tests.

  32. References • "Complete Blood Count (CBC): Results and Interpretation." WebMD. WebMD, 0000. Web. 17 Sept. 2013. <http://www.webmd.com/a-to-z-guides/complete-blood-count-cbc>. • Board, A.D.A.M. Editorial. CBC. U.S. National Library of Medicine, 19 Mar. 2012. Web. 17 Sept. 2013. <http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004108/>. • "Types of Blood Tests." Types of Blood Tests, Complete Blood Count. N.p., n.d. Web. 17 Sept. 2013. <http://www.nhlbi.nih.gov/health//dci/Diseases/bdt/bdt_types.html>. Images Taken From: • <http://www.healthtestingcenters.com/images/cbcresults.jpg> 15 Sept 2013 • <http://www.expertclinic.org/images/10416321/image001.jpg> 15 Sept 2013 • <http://medicine-science-and-more.com/wp-content/uploads/hematocrit3.jpg> 16 Sept 2013 • <http://upload.wikimedia.org/math/f/a/d/fad004d147730d8f3ba0c20c9a867a50.png> 15 Sept 2013 • <https://ahdc.vet.cornell.edu/clinpath/modules/hemogram/IMAGES/rdwlabeled.jpg> 15 Sept 2013 • <http://www.ouhsc.edu/platelets/platelets/Platelet%20Pics/Platelets%201.gif> 16 Sept 2013

  33. References • Working Group of Hypercholesterolemia and other Dyslipidemias • Genest, J., et al. 2003 Recommendations for the management of dyslipidemia and the prevention of cardiovascular disease: 2003 update. CMAJ. Oct 28, 2003; 169 (9) Online 1-10. • Heart & Stroke Foundation. • http://www.heartandstroke.com/site/c.ikIQLcMWJtE/b.3484027/ • Public Health Canada • http://www.phac-aspc.gc.ca/cd-mc/cvd-mcv/cholesterol_blood-cholesterol_sang-eng.php • National Health Services (NHS) • http://www.nhs.uk/chq/Pages/1018.aspx?CategoryID=69 • Narrowing of the arteries picture • http://www.cholesterol-loweringfoods.org/wp-content/uploads/2012/07/how-to-lower-ldl-cholesterol-plaque-artery.jpg • Lipoproteins vary in size and composition picture • http://www.healthcentral.com/common/images/1/19279_13509_5.jpg • Unsaturated triglyceride picture • http://campus.murraystate.edu/academic/faculty/eweber/bio101/images/Fat_triglyceride_shorthand_formula.PNG

  34. References • French, T. W. "Glycosylated Hemoglobin." Glycosylated Hemoglobin. Cornell University, n.d.n.d. • Marks, Marks, and Smith. “Ikke-enzymatiskglukosyleringavproteiner.” N/A. s.88, Web. n.d.n.d. • Little, Randie R., and William L. Roberts. "HbA1c: MedlinePlus Medical Encyclopedia."U.S National Library of Medicine. U.S. National Library of Medicine, 1 May 2009. n.d. • The International Expert Committee [on Diabetes]. "International Expert Committee Report on the Role of the A1C Assay in the Diagnosis of Diabetes." National Center for Biotechnology Information. U.S. National Library of Medicine, 28 Dec. 2005. n.d. • John, Matthew. "HbA1c : Glycosylated Hemoglobin." HbA1c : Glycosylated Hemoglobin. Providence Endocrine and Diabetes Specialty Centre, 12 Aug. 2010. Web. n.d. • Dansinger, Michael. "Diabetes Health Center." A1c Hemoglobin Levels Test for Diabetes: What's Normal?WedMD, 15 May 2012. Web. n.d.

  35. References Selker, HP et al. . "Creatine Kinase." Annals of Emergency Medicine. 29.1 (1997): 59-63. Web. 17 Sep. 2013. Teixeira, Ana Maria, and Grasiely F. Borges. "Creatine Kinase: Structure and Function." Brazilian Journal of Biomotricity. 6.2 53-60. Web. 17 Sep. 2013. Carey, Roberta, Robert Dufour, and et al, eds. "CK." Lab Tests Online. American Association for Clinical Chemistry, 25 Februrary 2013. Web. 17 Sep 2013. Dugdale, David. "Creatine Phosphokinase test." MedlinePlus. American Accreditation HealthCare Comission, 13 Februrary 2013. Web. 17 Sep 2013.

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