Lab Investigation In OMFS
- 1. LAB INVESTIGATIONS IN OMFS PRESENTED BY:– Dr. Mohd Akmal MODERATED BY:– Dr. Ishita
- 2. CONTENTS • INTRODUCTION • HEMATOLOGICAL INVESTIGATIONS • BIOCHEMICAL INVESTIGATIONS • MICROBIOLOGICAL INVESTIGATIONS • CONCLUSION
- 3. INTRODUCTION • Laboratory tests are an invaluable aid to the practicing oral & maxillofacial surgeons. • In conjunction with a thorough history and physical examination, laboratory tests aid in the diagnosis of various diseases. • Allow the precise preoperative and postoperative management of patients with systemic disease. • In addition, patients without overt disease can be screened before procedures that carry potentially serious complications, such as general anaesthesia , are begun.
- 4. HAEMOTOLOGICAL INVESTIGATIONS • 1. CBC • 2. COAGULATION TESTS • 3. CALCIUM • 4. PHOSPHORUS • 5. GLUCOSE • 6. GLYCATED HAEMOGLOBIN
- 5. COMPLETE BLOOD COUNT (CBC) • 1.Haemoglobin • 2.Total leukocyte count • 2.RBC Count • 3.Red Cell Distribution Width (RDW) • 4.Haematocrit / PCV • 5.MCV • 6.MCH • 7.MCHC • 8.WBC Count • 9.DLC • 10.Platelet Count
- 6. HAEMOGLOBIN CONCENTRATION • Defines anaemia ( Hb<lower limit of normal adjusted for age and gender) New Born 16.5-19.5 g/dl Children 11.2-16.5 g/dl Males 14.0-18.0 g/dl Females 12.0-16.0 g/dl
- 7. RED BLOOD CELL/ ERYTHROCYTE COUNT • Children - 4.5-5.1 million/mm3 • Males - 4.6-6.2 million/mm3 • Females - 4.2-5.4 million/mm3
- 8. Low RBC Count • Hypoprolioferative anaemias e.g. Iron, Vitamin B12 and Folate deficiencies. • Aplasias e.g. Idiopathic or drug-induced • Parvovirus B19 infection-induced red cell aplasia resulting in transient marked anaemia. High RBC Count • Polycythemia vera
- 9. HAEMATOCRIT OR PCV • It is the ratio of the volume of red blood cells to the total volume of blood. • Men : 47% • Women : 42% • High PCV - Polycythemia • Low PCV - Anaemia
- 10. MEAN CORPUSCULAR VOLUME (MCV) • Measurement of RBC size. • MCV = Normal PCV per 100 ml blood X 10 fL RBC count in million/microL • Normal value:- 80-96 femtolitres • Smaller size RBC:- Microcytes • Larger size RBC:- Macrocytes
- 11. Increase in MCV: Large (macrocytic) RBC—macrocytic anaemia as in vitamin B12 or folic acid deficiency. Decrease in MCV: Smaller (microcytic) RBC—iron deficiency and thalassaemia.
- 12. MEAN CORPUSCULAR HEMOGLOBIN • Macrocytosis • Microcytosis e.g.Iron deficiency anaema HIGH LOW Average amount of hemoglobin in a single RBC in picogram MCH = Hemoglobin in gm% X 10 pg RBC count in million/cumm Range – 28 -32 pg
- 13. MEAN CORPUSCULAR HEMOGLOBIN CONCENTRATION • Hemoglobin concentration in a single RBC. • MCHC = Hb in gm % X 100 • PCV per 100 ml blood • RBC's can not hold more than 37 g/dL of haemoglobin. • Increase in MCHC: Hyperchromic RBC—hereditary spherocytosis. • Decrease in MCHC: Hypochromic RBC—iron deficiency and thalassaemia.
- 15. TOTAL LEUCOCYTE COUNT • Increased • Decreased Acute infections, Uremia, Steroids,Hemorrhage,Leukemia Radiation,Aplastic anemia, Infectious mononucleosis,Septicemia
- 16. DIFFERENTIAL LEUCOCYTE COUNT • PMN : 40-75 % • Lymphocytes : 15-45 % • Eosinophils : 1-6 % • Basophils : 0-2 % • Monocytes : 1-10 %
- 17. Neutrophils(PMNs) - • Increased : Infections,Granulocytic leukemia,Surgery,Severe exercise • Decreased :Viral infections, Aplastic anemia, Drugs, Radiations, Dialysis. Eosinophils - • Increased : Allergic conditions, Parasitic infection, Collagen vascular diseases, Addison diseases, Malignancy • Decreased : Steroids, Stress ,ACTH excess, Cushing syndrome
- 18. Basophils- • Increased : Polcythemia, Chronic Myeloid Leukemia • Decreased : Steroids, Acute Rheumatic fever, Thyrotoxicosis Lymphocytes- • Increased : Viral infections, Tuberculosis, Mononucleosis • Decreased : Stress,Uraemia, Steroids,AIDS Monocytes- • Increased : Monocytic leukemia, Chronic inflammation or infection,Collagen diseases (RA, SLE), Protozoal infections, TB • Decreased : Hypoplastic bone marrow
- 19. PLATELET COUNT • Normal : 150000 – 400000/cumm • Low count : Thrombocytopenia • High count : Thrombocytosis
- 20. • Increased - • Malignancy • Post surgery • Post splenectomy • Rheumatoid arthritis (RA) • Iron deficiency anemia • Trauma • Acute hemorrhage • Decreased – • Idiopathic thrombocytopenic purpura (ITP) • Marrow invasion or aplasia • Hypersplenism • DIC • Cirrhosis • Quinidine • Massive transfusions • Viral infections • Infectious mononucleosis
- 21. COAGULATION TESTS - 1. Bleeding time 2. Clotting time 3. PT 4. PTT 5. INR
- 22. BLEEDING TIME - • 1-6 minutes • Increased : Thrombocytopenia , von Willebrand disease, Aspirin therapy CLOTTING TIME – • 6-10 minutes • Increased : Heparin therapy, Clotting factor deficiency
- 23. PROTHROMBIN TIME - • 12-14 seconds • Increased –Warfarin, Vitamin K deficiency, Liver disease, DIC, Deficiency of factors I, II, V, VII, X. PARTIAL THROMBOPLASTIN TIME ( PTT) - • 25-45 seconds • Increased – Heparin, Defects in intrinsic clotting mechanism, Haemophilia A and B, Prolonged use of tourniquet before drawing blood
- 24. Interpretation of PT and PTT in patients with bleeding disorders - PT prolonged , PTT normal • Liver disease, Decreased vitamin K, Decreased or defective Factor VII PT normal, PTT prolonged • Decreased or defective facor VIII,IX, or XI or anticoagulant present PT and PTT prolonged • Decreased or defective I, II, V, or X ,von Willebrand disease, Liver disease, DIC PT and PTT normal • Decreased platelet function ,Thrombocytopenia, Factor XIII deficiency, Mild von Willebrand disease
- 25. INTERNATIONAL NORMALIZED RATIO (INR) • Ratio of the patients PT to control PT standardized for the potency of the thromboplastin reagent developed by the World Health Organization (WHO) • INR = Patient PT • Control PT • Normal value < 1
- 26. • The guidelines of the American college of chest physician (ACCP) recommend dental surgery without vitamin K antagonists (VKA) interruption with use of a pro hemostatic agent. • The interruption of VKA treatment before dental procedures is not recommended for interventions that are unlikely to cause bleeding for low and high bleeding risk procedures if the INR of the patient is < 3.5 24 hours before the planned intervention. • If the INR > 3.5,the procedure should be delayed until INR values has been reduced to < 3.5. Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines
- 27. CALCIUM • 8.5 to 10.5 mg/dl • Increased : Hyperparathroidism, Hypervitaminosis D, Metastatic bone tumors, Pagets disease, Multiple myeloma, Sarcoidosis, Chronic renal failure. • Decreased : Hypoparathyroidism, Hypoalbuminemia, Renal failure, Alkalosis, Acute pancreatitis, Convulsions, Vitamin D deficiency.
- 28. PHOSPHORUS • 2.3 to 4.7 mg/dl • Increased : Hypoparathroidism, Chronic renal failure, Acidosis, Hypervitaminosis D, Addison s disease. • Decreased : Hyperparathyroidism,Alcoholism,Hypokalemia, Vitamin D deficiency, Alkalosis, Diabetes mellitus.
- 29. GLUCOSE • Increased : Diabetes mellitus, Stress, Hyperthyroidism, Pregnancy, Pancreatic disease, Steroid therapy, Cushing syndrome. • Decreased : Reactive hypoglycemia , Pancreatic disorders, Starvation, Liver disease, Hyperinsulinism, Hypothyroidism, Hypopituitarism, Addison disease, Sepsis.
- 30. FASTING PLASMA GLUCOSE (FPG) • Fasting blood sugar levels. • Not having anything to eat or drink for at least 8 hours before the test.
- 31. RANDOM PLASMA GLUCOSE TEST • This test is a blood check at any time of the day. • Diabetes is diagnose at blood sugar of > 200 mg/dl. Glycated Haemoglobin(Hb A1 c Fasting Plasma Glucose (FPG) Oral Glucose Tolerance Test (OGTT) Normal <5.7% <100 mg/dl <140mg/dl Prediabetes 5.7% to 6.4% 100 mg/dl to 125 mg/dl 140 mg/dl to 199 mg/dl Diabetes 6.5% or higher 126 mg/dl or higher 200 mg/dl or higher
- 32. GLYCATED HEMOGLOBIN TEST(HbA1c) • Determine how well you are managing your diabetes. • Glucose enters your red blood cells and links up (or glycates) with molecules of hemoglobin. • HbA1c reflects average plasma glucose over the previous 8 to 12 weeks.
- 34. Blood Chemistry Tests • Electrolytes • Anion gap • Renal function • Liver function
- 35. Electrolytes SODIUM – 135to 145 mEq/L • Increased- Dehydration, Glycosuria,Diabetes insipidus • Decreased- Diuretics, CHF,Hyperglycemia,Renal failure, Vomiting,Diarrhoea
- 36. CHLORIDE - • 95 to 108 mEq/L • Increased –Dehydration,Non anion gap metabolic acidosis,Diarrhoea, Diabetes insipidus • Decreased – Vomiting, Excess sweating,CHF,CRF, Diuretics, DM with ketoacidosis
- 37. POTASSIUM • 3.5-5.2 mEq/L • Increased –Renal failure,Adrenal insufficiency, Acidosis,Hemolysis • Decreased- Diuretics, Alkalosis, Vomiting,Nasogastric suctioning.
- 38. BICARBONATES • 24 to 30 mEq/L • Increased-Dehydration, Respiratory acidosis, Emphysema,Vomiting • Decreased- Metabolic acidosis,Respiratory alkalosis,Renal failure, Diarrhoea
- 39. Anion Gap • 8 to 12mEq • Difference in mEq between serum sodium and sum of serum chloride and bicarbonate • Normal – Diarrhoea, Renal tubular acidosis • Increased – Renal failure, Lactic acidosis, Ketoacidosis, Salicylate toxicity. • Decreased- DIC, Multiple myeloma
- 40. Renal Function Blood urea nitrogen (BUN) :-The end product of protein metabolism is urea, which is excreted entirely by the kidneys; therefore, the BUN is an indication of liver and kidney function • 6 to 20 mg/dL • Increased – Renal failure, Dehydration, GIT bleeding, Increesed protein catabolism. • Decreased – Liver damage, Protein deficiency, Starvation.
- 41. Creatinine Creatinine is formed when creatinine phosphate is used in skeletal muscle contractions, which is entirely excreted by the kidneys; therefore, the serum creatinine levels are an indication for renal function. The creatinine level is not affected by hepatic function so it is a more precise indication of renal function than is the BUN. A 50% reduction in glomerular filtration rate (GFR) doubles the creatinine level. • 0.7 to 1.4 mg/dl • Increased – Renal failure, Muscle disease • Decreased – Pregnancy
- 42. Urine Analysis Cloudy, foul smelling, WBCs—urinary tract infection (UTI) Dark yellow—dehydration Acetone odour—diabetic ketoacidosis Presence of protein—injured glomerular membrane Glucose—diabetes mellitus Ketones—fatty acid metabolism Crystals—renal stone formation possible Many hyaline casts—proteinuria Cellular casts—nephrotic syndrome
- 43. Liver function • Bilirubin • Alkaline phosphatase (ALP) • Gamma glutamyl transferase (GGT) • Alanine aminotransferase/serum glutamic pyruvic transaminase (ALT/SGPT) • Aspartate aminotransferase/serum glutamic oxaloacetic transaminase (AST/SGOT) • Albumin • Prothrombin time • Lactate dehydrogenase (LDH)
- 44. Indication Examples History or examination findings suggest liver disease • History of poisoning(e.g. Paracetamol) • Jaundice on examination • History of alcohol abuse • Signs of chronic liver disease including ascites • Family history of haemochromatosis Screening for population at high risk of blood borne virus infection • Contact tracing in cases of hepatitis • Indigenous patients • Illicit drug use • Previous transfusion Significant nonliver disease that may effect liver function • Malignancies • Hypoxia Monitoring medications • Valproate • Methotrexate Indications for Liver Function Tests
- 45. Serum Billirubin • 0.2 -1.0 mg/dl • Conjugated bilirubin - 0.2 -0.4 mg/dl • Unconjugated bilirubin – 0.2 – 0.6 mg/dl • Estimated by van den Bergh reaction
- 46. Alanine transaminase (ALT) Female: 7– 30 U/L Male: 10–55 U/L Aspartate transaminase (AST) Female: 7– 30 U/L Male: 10– 55 U/L Increased in: Hepatitis, cirrhosis, liver cancer, biliary obstruction (cholestasis), bone metastasis, congestive heart failure, muscle inflammation, infectious mononucleosis, shock, trauma. Drugs that increase: ACE inhibitors, acetaminophen, anticonvulsants, antibiotics, heparin, NSAIDs Increased in: Acute hepatocyte injury due to drugs (e.g. acetaminophen overdose), viruses (e.g. hepatitis A, hepatitis B), or ischaemia (e.g. myocardial infarction, Hepatitis, pancreatitis, liver CA. Decreased in: Beriberi, diabetic ketoacidosis, haemolysis, pregnancy, uraemia Drugs that increase: Acetaminophen, allopurinol, antibiotics, chlorpropamide, cholinergics, methyldopa, vitamin A Drugs that decrease: Metronidazole
- 47. Alkaline Phosphatase (ALP) Female: 30–100 U/L Male: 45– 115 U/L Increased in: Biliary obstruction, bone metastasis, calcium deficiency, CA pancreas, cirrhosis, eclampsia, fracture, hepatitis, high fat intake, hyperparathyroidism, infectious mononucleosis, leukaemia, CA liver, osteogenic sarcoma, osteomalacia, Paget's disease, pancreatitis, pregnancy, RA, rickets, vitamin D deficiency. Decreased in: Cystic fibrosis, excessive vitamin D intake, hypophosphataemia, perinicious anaemia, celiac disease, chronic nephritis, scurvy. Drugs that increase: ACE inhibitors, anticonvulsants, heparin, NSAIDs, oestrogens. Drugs that decrease: Fluorides, propranolol
- 48. Gamma Glutamyl Transferase (GGT) Female: 5– 29 U/L Male: 5–38 U/L Increased in: Acute pancreatitis, alcoholism, biliary obstruction, cholecystitis, cholelithiasis, cirrhosis, hepatitis, MI, renal cancer, SLE GGT is a sensitive marker of alcohol ingestion and certain hepatotoxic (liver toxic) drugs Marker of cholestasis, but may be due to alcohol and other drugs through enzyme induction Drugs that increase: Aminoglycosides, barbiturates, NSAIDs, phenobarbital, phenytoin. Drugs that decrease: Oral contraceptives.
- 49. Total protein- 6.0 to 8.5 g/dl • Increased –Multiple myeloma, Dehydration, Sarcoidosis • Decreased – Liver failure, Starvation, Inflammatory bowel disease Albumin – 3.5- 5.0 g/dl • Increased – Dehydration • Decreased- Liver failure, Starvation, Hyperthyroidism, Leukemia, Nephrotic syndrome
- 50. Microbiology • 1.HIV • 2.HbsAg • 3.VDRL
- 51. 1.HIV • Enzyme-linked immunosorbent assay(ELISA) (Screening test) • Western blot -Used for confirming presence of HIV antibody • Positive – AIDS.
- 52. 2.HbsAg • Hepatitis B virus (HBV) • A ‘positive’ or ‘reactive’ HbsAg test result means that the person is infected with hepatitis B. • Can spread the hepatitis B virus to others through blood.
- 53. 3.VDRL • Venereal disease research laboratory test • Screening test for syphilis. • If positive,confirm the results with an FTA-ABS test
- 54. Special Investigations- • 1.CRP • 2.Blood Gases
- 55. C-reactive protein(CRP) • Acute phase protein • Normal value-Less than 10 mg/l • Sensitive systemic marker of inflammation and tissue damage. • During infectious or inflammatory disease states, CRP level rise rapidly within the first 6 to 8 hours and peak at levels of up to 350- 400 mg/L after 48 hours. • CRP, binds to pathogens and activates the complement to enhance opsonisation and clearance, even before the production of specific IgM or IgG.
- 56. Higher level seen in- • Late pregnant women • Mild inflammation and viral infections(10-40 mg/L) • Acute inflammation • Bacterial infection(40-200 mg/L) • Burns(>200mg/L)
- 57. Blood Gases - Indications for measurement- • Altered ventilatory status : Stroke,Asthma,COPD • Hypoxemia : Pneumonia • Hypocapnia : Hyperventilation • Hypercapnia : COPD • pH disturbance : Ketoacidosis
- 58. Normal Values – Arterial Blood Sample • pO2- 80-95 mmHg • SaO2 – 93% to 98% • pCO2- 36 to 43 mmHg • HCO3 – 20-30 mEq/L • Arterial pH -7.35-7.45
- 59. Interpretation of Arterial Blood Gas Results - • Arterial pH • <7.35 =Acidosis • 7.35 to 7.45 = Normal,Compensated or mixed disorder • >7.45 = Alkalosis
- 61. Routine preoperative tests for elective surgery –NICE guidelines 2016
- 66. Conclusion- • Preoperative laboratory tests should be ordered bases on defined indications such as positive findings on a history and physical exam. • A thorough history and physical examination can be used to identify those medical conditions thar might affect perioperative management and direct further laboratory testing.
- 67. References- • Textbook of Biochemistry,Dr. U Satyanarayana • Textbook of Physiology,6th edition,AK jain • Clinicians handbook of Oral & maxillofacial surgery, Daaniel M.Laskin • Routine preoperative tests for elective surgery –NICE guidelines 2016
Editor's Notes
- #7: A fall in haemoglobin concentration below 10 g/dL is considered low. A fall in haemoglobin below 6 g/dL in a young individual indicates need for packed cell transfusion.
- #9: Pol
- #12: RBC with normal volume –Normocytes RBC with less than normal volume - Microcytes
- #15: If MCHC is less than normal range - Hypochromic
- #22: This condition predisposes to bleeding and hypo-coagulability. • Low 50,000–1,50,000 per cubic mm—no signs of spontaneous bleeding • Very low 20,000–50,000 per cubic mm—prolonged bleeding • High risk less than 20,000 per cubic mm—spontaneous bleeding
- #25: Clotting time (CT) is measured as the time taken for the blood to form fibrin bands or thrombus.
- #26: Prothrombin time (PT) is used to assess efficient functioning of the coagulation process. The partial thromboplastin time (PTT) is used to appraise the proper functioning of the coagulation cascade by measuring the time taken for a clot to form in a plasma sample to which calcium and partial thromboplastin have been added.
- #53: • GGT is an enzyme that is found in the liver and biliary tract and to a lesser degree in the heart, kidneys, pancreas, prostate gland and spleen. Its function is to assist in amino acid transport across cell membranes
- #56: Enzyme-linked immunosorbent assay systems involving use of antigens, haptens or antibodies labelled with an enzyme for measurement of substances in biological fluids. A capture antibody specific to the antigen in question is bound to the wells of plastic micro-dilution trays. Then the clinical specimen suspected to contain the microbe and therefore the antigen is incubated in the wells. The wells are then washed. A second antibody for the antigen, labelled with enzyme, is used to detect the antigen. The antigen is then detected colorimetrically by adding the substrate for the enzyme. Western blot: Another form of EIA, to detect antibody, is immunoblotting (Western blot), whereby defined antigens are placed on strips of nitrocellulose paper. Following incubation with the test antibody-containing specimen, the strip is further treated with an enzyme-labelled antibody, usually from another animal, against the test antibody. Addition of the substrate for the enzyme allows detection of the antigen-specific bound antibody by colorimetric reaction. Western blot tests are used as the confirmatory tests for antibodies in HIV infection and Lyme disease
- #61: Acute and chronic inflammation, Tissue injury