Lab. investigations in oral surgery.seminar.pptx

investigations in oral surgery

1. Essentials of LAB INVESTIGATIONS preoperatively Ahmed jameel mohammed Oral & maxillofacial dep. 26.NOV.2023

2. CONTENTS INTRODUCTION HEMATOLOGICAL INVESTIGATIONS BIOCHEMICAL INVESTIGATIONS MICROBIOLOGICAL INVESTIGATIONS CONCLUSION

3. INTRODUCTION Laboratory tests are valuable aid to practicing oral & maxillofacial surgeries. 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 anesthesia, neck dissection and tumor excision .

4. Lab. Investigation categorized to : HEMATOLOGICAL INVESTIGATIONS BIOCHEMICAL INVESTIGATIONS MICROBIOLOGICAL INVESTIGATIONS

5. COMPLETE BLOOD COUNT (CBC) A complete blood count (CBC) is a blood test used to look at overall health and find a wide range of conditions, including anemia, infection and leukemia.

6. COMPLETE BLOOD COUNT (CBC)

7. HAEMOGLOBIN CONCENTRATION Hemoglobin is a protein in red blood cells that carries oxygen to body's organs and tissues then transports carbon dioxide back to the lungs . Defines anaemia . New Born 16- 19 g/dl Children 11- 16 g/dl Males 14.0- 18.0 g/dl Females 12.0- 16.0 g/dl

8. RED BLOOD CELL/ ERYTHROCYTE COUNT

9. Low RBC Count /HB Hypo proliferative 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 anemia. High RBC Count /HB p olycythemia Vera Smoking Use of testosterone Low oxygen level in the blood for a long time, most often due to heart or lung disease.

10. HAEMATOCRIT OR PCV It is the ratio of the red blood cells volume to the total volume of blood. Male : 47% female : 42% High PCV - Polycythemia Low PCV - Anemia

11. MEAN CORPUSCULAR VOLUME (MCV) Measurement of RBC size . Larger size RBC: Macrocytes Smaller size RBC:- Microcytes

12. Smaller size RBC:- Microcytes iron deficiency and thalassaemia . Larger size RBC: Macrocytes vitamin B12 or folic acid deficiency.

13. MEAN CORPUSCULAR HEMOGLOBIN CONCENTRATION Hemoglobin concentration in a single RBC. RBC's can not hold more than 37 g/dL of haemoglobin .

14. TOTAL LEUCOCYTE COUNT

15. A decreased WBC count is called leukopenia , may be due to: Alcohol abuse and liver damage Autoimmune diseases (such as systemic lupus erythematosus ) Bone marrow failure (for example, due to infection, tumor, radiation, or fibrosis) Chemotherapy medicines used to treat cancer Disease of the liver or spleen Enlarged spleen Infections caused by viruses, such as mono or AIDS Medications

16. A high WBC count is called leukocytosis . It can result from: Certain medicines, such as corticosteroids. Infections. Diseases such as rheumatoid arthritis, or allergy. Leukemia. Severe emotional or physical stress. Tissue damage (from burns or a heart attack).

17. PLATELET COUNT High count : Thrombocytosis Normal : 150000 – 400000 cell/mm 3 Increased - Malignancy Post surgery Post splenectomy Rheumatoid arthritis (RA) Iron deficiency anemia Trauma Acute hemorrhage Low count : Thrombocytopenia Decreased – Idiopathic thrombocytopenic purpura (ITP) Marrow invasion or aplasia Hypersplenism Cirrhosis Massive transfusions Viral infections

18. COAGULATION TESTS

19. CLOTTING TIME – 6- 10 minutes Increased : Heparin therapy , Clotting factor deficiency BLEEDING TIME - 1- 6 minutes Increased : Thrombocytopenia , von Willebrand disease, Aspirin therapy

20. PROTHROMBIN TIME - 12- 14 seconds Increased –Warfarin, Vitamin K deficiency, Liver disease , Deficiency of factors I, II, V, VII, X. PARTIAL THROMBOPLASTIN TIME ( PTT) - 25- 45 seconds Increased – Heparin, Defects in intrinsic clotting mechanism, Hemophilia A and B, Prolonged use of tourniquet before drawing blood (Calcium breakdown)

21. INTERNATIONAL NORMALIZED RATIO (INR) Ratio of the patients PT to control PT INR monitoring is most commonly required for the patients who are on warfarin (a vitamin K antagonist).   Normal value ≤ 1 .1

22. 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.

23. 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.

24. Blood glucose level 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.

25. FASTING PLASMA GLUCOSE (FPG) Fasting blood sugar levels. Nothing taken orally for at least 8 hours before the test.

26. RANDOM PLASMA GLUCOSE TEST Check glucose at any time of the day. Diabetes is diagnose at blood sugar of > 200 mg/dl. The oral glucose tolerance test (OGTT ) I s currently the gold standard for the diagnosis of diabetes. reading is based on plasma glucose results before and 2 hours after a 75g oral glucose load.  

27. GLYCATED HEMOGLOBIN TEST(HbA1c) Determine how well diabetes is being managed 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.

28. Glycated Haemoglobin(Hb A1C) 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

29. Renal Function T Blood urea nitrogen (BUN) :- The end product of protein metabolism in liver is urea , which is excreted entirely by the kidneys; therefore, the BUN is an indication o f liver and kidney function 6 to 20 mg/dL Increased – Renal failure, Dehydration, GIT bleeding, Increesed protein catabolism. Decreased – Liver damage, Protein deficiency, Starvation.

30. 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 (increased renal blood flow )

31. 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

32. Microbiology

33. 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 tha t might affect perioperative management and direct further laboratory testing.

34. References- Textbook of Biochemistry,Dr. U Satyanarayana Textbook of Physiology,6 th edition,AK jain Clinicians handbook of Oral & maxillofacial surgery, Daaniel M.Laskin Routine preoperative tests for elective surgery –NICE guidelines 2016