This document provides an overview of laboratory investigations in dentistry. It defines laboratory investigations, outlines their need and applications. It then classifies laboratory investigations and discusses the most common hematological, biochemical, microbiological, immunological, and histopathological/cytopathological investigations. Specific tests are explained in detail including complete blood count, erythrocyte sedimentation rate, bleeding time, and platelet count. The significance and interpretation of results for these common dental laboratory tests are also summarized.

1. Presented by:
Dr.Sachidanand Giri
JR-3

2. 1. Definition
2. Need for Lab investigations
3. Applications
4. Classifications
5. Laboratory Investigations (Frequently and
infrequently required)
a. Haematological Investigations
b. Biochemical Investigations

3. c. Microbiological Investigations
d. Immunological Investigations
e. Histopathological and Cytopathological
Investigations
7. Conclusion
8. References

4.  Laboratory studies are an extension of physical examination in which tissue, blood, urine
or other specimens are obtained from patients and subjected to microscopic, biochemical,
microbiological or immunological examination.
 Information obtained from these investigations help us in identifying the nature of the
disease.
4

5.  Evidence shows Case History and Clinical examination usually reveal most of ,but not
all of clinically relevant data.
 The provisional diagnosis can be made on the basis of case history and clinical
examination but for definitive diagnosis laboratory investigations are required
 Lab investigations supplement rather than replace other methods for gathering
information
 It is a known fact that with the help of lab investigations, some underlying systemic
conditions of which the patients are unaware of, are often identified in dental practice
for the first time

6.  Confirming or rejecting clinical diagnosis
 Providing suitable guidelines in patient management
 Providing prognostic information of the diseases under consideration
 Detecting diseases through case-finding screening methods
 Establishing normal baseline values before treatment
 Monitoring follow up therapy
 Providing information for Medico-Legal consultations
6

7.  Based on where investigation is done:
7
Chair side Investigations Laboratory Investigations
Acts as a precursor to laboratory
investigations
Significantly higher sensitivity
and specificity
Egs : Toluidine blue staining for
grading dysplasia, Electric Pulp
testing for tooth vitality,
Egs: Glycated Haemoglobin
estimation,
Peripheral smear histology

8.  Based on specificity/sensitivity:
8
Screening Tests Diagnostic Tests
An ideal screening test is 100%
sensitive
An ideal diagnostic test is 100% specific
Useful in a large sample size at risk;
typically cheaper
Useful in symptomatic individuals to establish
diagnosis or asymptomatic individuals with +ve
screening test; expensive
Egs : blood glucose estimation for
screening diabetes,
Haematocrit values for anaemia,
VDRL test for syphilis
Egs: Glycated Haemoglobin estimation, OGTT
Peripheral smear histology

9.  Based on Hospital Lab Services:
9
Haematology
Histopathology
Biochemistry
Immunology
Urinalysis Biochemistry
Cytopathology

10.  Based on frequency of dental use: (by Sonis, Fazio & Fang )
10
Frequently used:
• CBC- Hb, Hct, Absolute
and differential WBC
• Bleeding studies – BT,CT,
PT, aPTT
• Peripheral Blood Smear
• Random Blood Glucose
Occasionally done:
• Tests for disturbance of
bone – Ca, P, ALP
• ESR
• Urinalysis
• Screening Test for
Syphilis
Rarely ordered:
• Enzyme testing
• Bilirubin Estimation
• Creatinine
Estimation
• Acid Phosphatase
• BUN

11. SIGNIFICANCE OF BLOOD INVESTIGATION
Blood investigation helps in diagnosing
• Leukopenia
• Thrombocytopenia
• Myeloma
• Anemia *Iron deficiency
*Aplastic
*Sickle cell anemia
• Thalassemia
• Acute and Chronic leukemia
• liver disease
• Myxedema
•Diabetes

12. COLLECTION OF BLOOD SAMPLE
•CAPILLARY BLOOD SPECIMENS: The
specimen is obtained by pricking the patient`s
finger .
•VENOUS BLOOD SPECIMEN: Most
Commonly used method. Venipuncture is
usually performed in ANTECUBITAL vein.

13. •WBC count
•Differential
Leukocyte count
•RBC count
•Hemoglobin
•Hematocrit
•Erythrocytes indices
•Platelet Count
•Bleeding time
•Capillary Fragility Test
•Clotting Time
•Erythrocyte Sedimentation Rate
TYPES OF HEMATOLOGICAL
INVESTIGATIONS
Complete Blood
Count

14. COMPLETE BLOOD COUNT
Complete blood count (CBC) is one of the most commonly ordered blood tests.
The complete blood count is the calculation of the cellular (formed elements) of blood.

15. What are the components of the complete blood count (CBC)?
The complete blood count, or CBC, lists a number of many important values. Typically, it
includes the following:
• White blood cell count (WBC or leukocyte count)
• WBC differential count
WBC
• Red blood cell count (RBC or erythrocyte count)
• Hematocrit (Hct)
• Hemoglobin (Hbg)
• Mean corpuscular volume (MCV)
• Mean corpuscular hemoglobin (MCH)
• Mean corpuscular hemoglobin
concentration (MCHC)
RBC
• Platelet countPLATELET

16. •White blood cell count (WBC) is the number of white blood cells in a volume
of blood.
• Normal range of WBC= 4,500 - 10,000 cells/mm3 of blood.
WBC/Leukocyte Count

17. Specific causes of Leukocytosis:
1. Infection- Acute and Chronic
2. Leukaemia
3. Polycythemia
4. Trauma
5. Exercise , Stress and fear
6. After general anesthesia
7. Allergy
8. Drugs, such as corticosteroids and epinephrine
9. Rheumatoid arthritis
10. Smoking

18. Specific causes of Leukopenia:
1. Aplastic anaemia
2. Influenza, measles and Respiratory tract infection
3. Early Leukaemia
4. Depression of Bone marrow
5. Drug and chemical toxicity
6. Shock

19. WBC
Granulocytes
Neutrophils Eosinophils Basophils
Agranulocytes
Lymphocytes Monocytes
White blood cell (WBC) differential count:
White blood cells are comprised of several different types of cells that are
differentiated, or distinguished, based on their size and shape.
Differential CountWBC

20. Normal values:
• Granulocytes (or polymorphonuclears)
Neutrophils: 43-77% (3000-7000)
Eosinophils: 0-4% (50-200)
Basophils: 0-2% (0-100)
• Agranulocytes (or mononuclear)
Lymphocytes: 17-47 %(1000-3500)
Monocytes: 2-9%(100-600)

21. CLINICAL SIGNIFICANCE
Neutrophils
INCREASES in: DECREASES in:
Inflammatory disease Aplastic Anaemia
Stress Cyclic Neutropenia
Exercise Malignant Neutropenia
Pregnancy Early Leukemia
Acute Infection
Excitement
Eosinophils
INCEASES in: DECREASES in:
Parasitic infections Immune defect
Hypersensitivity/ Acute stress
Allergic responses Typhoid Fever
Scarlet Fever Aplastic Anaemia

22. Basophils
INCREASES in: DECREASES in:
Chronic leaukemia Acute Infection
Myelofibrosis Severe injury
Polycythemia
Lymphocytes
INCEASES in: DECREASES in:
Lymphocytic Leukemia Aplastic Anaemia
Mumps
Whooping Cough
Chronic Infection

23. Monocytes
INCREASES in: DECREASES in:
Monocytic leukemia
Hodgkin disease Aplastic Anaemia
Malaria – Kala -azar
SABE
TB
Infectious mononucleosis

24.  Most common sign of neutropenia is ulceration of oral mucosa.
 Ulcers lack surrounding inflammation and are characterized by necrosis.
 Advanced periodontal disease,paricoronitis, pulpal infections.
 Most common sign of leukemia- cervical lymphadenopathy
 Others-pallor of the mucosa, petechiae,echymosis, gingival bleeding,
oral ulcers, oral infections(candidiasis)

25. RBC Count
•Red Blood cell count (RBC) signifies the number of red blood cells in a volume of
blood.
• Normal range : 4.2 to 5.9 million cells/cmm.
• This can also be referred to as the Erythrocyte count
• It can be expressed in international units:4.2 to 5.9 x 1012 cells
per liter.

26. •An increase in red blood cell mass is known as Polycythemia.
•PV is a chronic myeloproliferative disease characterized by a predominant proliferation of the erythroid
cell line.
•Oral manifestations: purplish red discoloration of oral mucosa, gingivae and tongue,
•Gingivae are markedly swollen and bleed spontaneously but not ulcerated
•Petechiae are common
•Severe hemorrhage after dental extractions and periodontal surgery
•Smokers also have a higher number of red blood cells than non-smokers.
INCREASE in RBC Count

27. DECREASE in RBC Count
•Massive RBC loss, such as acute hemorrhage
• Abnormal destruction of red blood cells
• Lack of substances needed for RBC production
• Chemotherapy or radiation side effects from treatment of bone marrow malignancies
such as leukemia can result in bone marrow suppression.

28. HEMOGLOBLIN
Hemoglobin is the protein molecule within red blood cells that carries oxygen and gives
blood its red color.
•Normal range =13-18 grams per dl for men and
12-16 grams per dl for women

29. A low haemoglobin count can also be due to blood loss
Diseases and conditions that cause the body to destroy red blood cells faster than
they can be made:
• Enlarged spleen (splenomegaly)
• Sickle cell anemia
• Thalassemia
• Vasculitis

30. •It is a measure of volume percent of packed red blood cells to that of whole blood.
Normal results :
Male: 40.7 - 50.3%
Female: 36.1 - 44.3%
Hematocrit (Hct)

31. Erthrocytes Indices
•To evaluate the nature of Anaemia, assistance is obtained by calculating standard indices
relating to the size of RBCs.
•By measuring these indices we can classify anaemia as Microcytic, Macrocytic And
Normocytic and Hypochromic and Normochromic.
Types
MCH MCHC MCV

32. The Haemoglobin content of erythrocyte is referred to as the Mean Corpuscular
Haemoglobin(MCH) expressed in picogram of haemoglobin per cell.
MCH = Haemoglobin concentration (g/dl) × 100
RBC in million/mm3
Mean Corpuscular Haemoglobin (MCH)

33. The concentration of Haemoglobin in the erythrocyte is referred to as the Mean Corpuscular
Haemoglobin Concentration.(MCHC) expressed in picogram of haemoglobin per cell.
MCHC = Haemoglobin concentration (g/dl) × 100
Hematocrit
Mean Corpuscular
Haemoglobin Concentration (MCHC)

34. The average red cell volume is referred to as the Mean Corpuscular Volume(MCV) .
It is expressed in cubic microns per cell.
MCHC = Hematocrit × 100
RBC in million /mm3
Mean Corpuscular Volume (MCV)

35. Different types of Anaemia and Indices
Types of Anemia MCV MCH MCHC
Microcytic
Hypochromic
Decreased Decreased Decreased
Macrocytic
Normochromic
Increased Increased Normal
Normocytic
Normochromic
Normal Normal Normal

36.  The common causes of Microcytic & Hypochromic Anemia (decreased
MCV and MCH) are:
• Iron deficiency anemia
• Anemia of chronic disease
• Thalassemia
• Sideroblastic anemia

37.  Angular cheilitis (58%),
 Glossitis with different degrees of atrophy of fungiform and filliform papillae
(42%),
 Pale oral mucosa
 Oral candidiasis
 Recurrent aphthous stomatitis
 Erythematous mucositis
 And burning mouth for several months to 1 year’s duration.

38. The common causes of Macrocytic Anemia (increased MCV and MCH) are as
follows:
•Folate or Vit B12 deficiency anemia
•Liver disease
•Hemolytic or Aplastic anemias
•Hypothyroidism
•Excessive alcohol intake
•Myelodysplastic syndrome

39.  Patients with pernicious anemia may have complaints of:
 Painful glositis and glosopyrosis-early symptoms
 Sore tongue, Dysphagia
 Burning sensation in the tongue, lips, buccal mucosa, and other mucosal
sites.
 The tongue and mucosa may be smooth or patchy areas of erythema.
And loss of taste sensation

40. The common causes of Normocytic And Normochromic Anemia (normal
MCV, MCH and MCHC) are:
•Anemia of chronic disease
•Acute blood loss
•Hemolytic anemia, such as autoimmune hemolytic anemia, hereditary
spherocytosis, or nonspherocytic congenital hemolytic anemia (G6PD deficiency,
other)
•Anemia of renal diseases.

41.  Pallor of oral mucosa especially evident in soft palate, tongue,
sublingual tissues
 Paresthesia of mucosa
 For those with chronic conditions, hyperplastic marrow spaces
 In the mandible, maxilla, and facial bones

42. PLATELET/THROMBOCYTE COUNT
The number of platelets in a specified volume of blood.
Platelets play a vital role in Haemostasis.
Normal range (Adult) =150,000 to 400,000/ cmm of blood.
(150 to 400 x 109/ L)
Normal range(Children) =150,000-450,000 /cmm of blood.
(150-450 x 109/L)

43. Interpretation of Platelet count
THROMBOCYTOSIS:
Post operative phase
Pregnancy
Post partum phase
Haemolytic Anemia
Trauma
Polycythemia vera
Chronic myelocytic leukemia
THROMBOCYTOPENIA:
Acute leukemia
Idiopathic thrombocytopenic purpura
Aplastic anemia
Effect of chemotherapy
Hypersplenism

44. •It is the measure of the rate at which RBCs sediments in a period of one hour.
•Also called as Sedimentation Rate or Westergren ESR
•It is a non-specific measure of inflammation.
•Also helpful in following progress of some chronic infections (TB and
Osteomylelitis)
Normal ESR
Male: 0-15 mm per hr
Female: 0- 20 mm per hr
Erythrocyte Sedimentation Rate (ESR)

45. Interpretation of ESR
ESR increased:
Tuberculosis
Osteomyelitis
Rheumatic fever
Myocardial infarction
Rheumatoid arthritis
Hodgkin's disease
Leukaemia
ESR decreased:
Congestive cardiac failure
Polycythemia
Severe dehydration like cholera
Physiologic condition where ESR is
increased:
Pregnancy: After intake of full meal

46. It Measures the time required for hemostatic plug to form.
Lack of any clotting factor or platelet abnormalities will prolong the bleeding time.
It is used to screen disorders of platelet function and thrombocytopenia
Normal Bleeding Time: 2 - 6 minutes
Methods are: Duke method (7-8 min)and Ivy’s method(5-6min)
BleedingTime

47. An abnormal Bleeding time- It is usually the result of abnormalities in the structure /
abilities of capillaries to contract or abnormalities in the number (Thrombocytopenia)
and functional integrity of platelets.
Interpretation of bleeding time

48. Prolonged in:
Thrombocytopenia
Acute leukaemia
Aplastic anaemia
Liver diseases
Von-Willebrand’s disease

49. •It is the test of the ability of superficial capillaries of the skin of the
forearm and hands to withstand an increased intra-luminal pressure and a certain
degree of hypoxia.
It is done by occluding the upper veins of the upper arm with a blood pressure cuff
for five minutes.
Also known as Tourniquet Test/ Rumpel Leede Test
Capillary FragilityTest

50.  Indication:
 1. Bleeding abnormalities
 2. Petechiae in oral cavity
 3. Scurvy
 Positive result: unequivocal petechiae seen distal to cuff.(15-20/2.5cm2)
 Negative result: If only 1 or 2 petechiae seen distal to cuff.

52. Time required for coagulation to occur in a sample of whole blood outside the body
is known as Clotting Time.
Normal time- 3 to 7 minutes
Method are:
• Capillary tube method
• Le and white’s test tube method
ClottingTime

53. An abnormal Clotting time- It is usually prolonged in diseases affecting stages of
coagulation.
It is also increased in:Cirrhosis
Hemophilia A and B
Factor XI deficiency,
Hypofibringenemia and
Heparin & Dicumarol therapy.
Interpretation of Clotting time

54. HEMATOLOGICAL
INVESTIGATIONS
(not so frequent in dentistry)
•Prothrombin Time
•Partial Thromboplastin Time
•INR

55. It is the time in seconds that is required for development of a clot in citrated or
oxalated plasma, where known amount of tissue thromboplastin and calcium is
added.
It is used to check the extrinsic pathway factor (F 7) and the common pathway ( F 5,
10 , prothrombin and fibrinogen).
Normal range: 11 to 15 seconds
Prolonged time (>3 times) indicates a hemorrhagic tendency.
It gets prolonged when plasma level of any factor is below 10% of its normal value
PROTHROMBINTIME

56. Prothrombin Time (PT):
 Increased PT
 Disseminated Intravascular Coagulation
 Patients on Warfarin Therapy
 Vit K deficiency
 Early & End stage Liver failure
56

57. It is the time in seconds that is required for a clot to form in a sample of oxalated
plasma, to which a partial thromboplastin reagent and calcium is added.
It is used to check the intrinsic system (8, 9, 11, 12) and the common pathways (5,
10, prothrombin and fibrinogen).
Normal range: 25-35 seconds
If PTT is prolonged it indicates deficiency of factor 8 or 10
PARTIALTHROMBOPLASTINTIME

58. INR:
INTERNATIONAL NORMALIZED RATIO
The International Normalised Ratio (INR) is a laboratory measurement of how
long it takes blood to form a clot. It is used to determine the effects of oral
anticoagulants on the clotting system.
It is the ratio of Patient’s Prothrombin Time to that of normal Prothrombin time.
INR= Patient`s PT
Normal PT

59.  It should be noted that INR is used to monitor Anti coagulant therapy & NOT be
used as coagulation screening test
 INR values of 5.0 or greater indicate a serious risk of spontaneous bleeding
episodes.
NORMAL RANGE: 0.8-1.2 (No anticoagulant therapy)
02-03 (On anticoagulant therapy)
• Infiltration anesthesia , scaling and root planningINR <3
• Block anesthesia , minor surgery , extractionINR <2
• Major surgeryINR <1.5

60. Serum Iron and Total Iron Binding Capacity:
 Iron deficiency is usually detected on the basis of the amount of iron
bound to transferrin in the plasma(serum iron) and the total amount of
iron that can be bound to the plasma transferrin in vitro.
 Normal values
 Serum iron – 80-180 µg/dl
 TIBC – 250 – 370 µg/dl
60

61. 61

62. Glycated
Haemoglobin(HbA1
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

63. High values are seen in Diabetes mellitus, Cushing’s disease,
pheochromocytoma, in patients taking corticosteroids
Low values seen in insulin secreting tumours, Addison’s, Pituitary
hypo function
63

64. Oral Glucose Tolerance Test:
 Used for the definitive diagnosis of diabetes mellitus and for
distinguishing diabetes from other causes of hyperglycaemia
like hyperthyroidism
 Should be performed on only healthy ambulatory patients
who are not under any drugs which may interfere with
glucose estimation
64

65. Glycated Haemoglobin(HbA1c):
Hb becomes Glycated by ketoamine reactions between glucose and other
sugars.
Once Hb is Glycated, it remains that way for a prolonged period(2-3
months)
Hence it provides a definitive value of blood sugar control of 2-3 month
duration
The HbA1c fraction is abnormally elevated in diabetic patients with chronic
hyperglycaemia
It is considered to be a better indicator for diabetic control compared to
blood glucose levels.
65

66.  Mucosal conditions include oral dysesthesia, including burning mouth,
 Altered wound healing,
 Increased incidence of infection,candidal infections (particularly acute pseudomembranous candidiasis of
the tongue, buccal mucosa, and gingiva).
 Xerostomia and bilateral generalized salivary gland enlargement or sialadenitis (especially in the parotid
glands) can occur and both are often related to poor glycemic control
 High incidence of dental caries.
 Dry mucosal surfaces
 Gingivitis and periodontitis
 Poor wound healing

67. Serum Calcium, Phosphorus:
 Indicated on suspicion of Paget’s disease, fibrous dysplasia, primary and secondary
hyperparathyroidism, osteoporosis, multiple myeloma or osteosarcoma
 The concn. of Serum Ca varies inversely with serum P
 Normal level Serum Ca – 9.2-11 mg/dl
 Normal level Serum P – 3- 4.5 mg/dl
 At levels less than 7 mg/dl Serum Ca, signs of tetany(n-m excitability,+ve chvostek’s
sign) may appear.
67

68. Serum Alkaline Phosphatase: (ALP)
 ALP produced in small amounts in the liver but most notably in osteoblasts
 Normal values:
68
ADULT CHILD
KingArmstrong Units 3-13 15-30
Bodansky Units 1-4 5-14
International Units
(IU/l)
30-110

69. Serum Alkaline Phosphatase: (ALP)
69
High values Low values
Obstructive liver disease Hypophosphatasia
Paget’s disease of bone
hyperparathyroidism
Hypothyroidism
Osteomalacia Osteoporosis
Rickets Aplastic/Pernicious anaemia
Sarcoidosis Chronic Myeloid Leukaemia
Lymphoma Wilson’s Disease

70. Serum Alkaline Phosphatase: (ALP)
 This test is very useful for diagnosing biliary obstruction.
 Even in mild cases of obstructive disease, this enzyme is elevated.
 It is not very useful for diagnosing cirrhosis.
 If a patient has bone disease, this test may be highly inaccurate, as ALP
is also found in bone tissue.
70

71.  Normal value:200-400U/L (LDH)
 For CPK male: 5-35 ug/ml (mcg/ml);
female: 5-25 ug/ml
newborn: 10-300 IU/L

72.  Iso-enzymes of CPK are:
 CPK-1 (BB)
 CPK-2(MB)
 CPK-3(MM)
 LDH1-2 : heart fractions
 LDH5:liver fraction
 LDH234:acute leukemia,chronic myelogenous leukemia, infectious
mononucleosis, lymphomas
 In heart attack: CPK increase in 4 hours, SGOT in 12 hours, increase in
LDH 1-2 days later

74. Total Protein & Albumin/Globulin Ratio:
 These proteins are important in coagulation, transport a variety of
hormones, act as buffer systems and help maintain osmotic pressure
 Normal range:
Total protein – 6 – 8.3 g/dL
A/G ratio - 1.2 – 2.0
74

75.  Elevation: multiple myeloma, systemic lupus erythematosus,
amyloidosis, collagen diseases ets.
 Serum protein electrophoresis: albumins,fibrinogen,
globulins(alpha1,alpha2,beta,gamma),agammaglobulinemias
 Immunodifusion- IgA, IgM, IgG, IgE

76.  Normal value:
 Total cholestrol :75-169 mg/dL for those age 20 and younger
100-199 mg/dL for those over age 21
 HDL: >40 mg/dl
 LDL: <130 mg/dl
 TRIGLYCERIDES: <150 mg/dl

77. Liver function tests(LFT) are helpful to detect the abnormalities and extent of liver
damage.
LFT assays are frequently more sensitive than clinical signs and symptoms.
Typically the LFT comprises of:
 Total protein
 Albumin and globulin
 (Prothrombin Time)
 Transaminases – AST & ALT
 Alkaline PO4ase
 Bilirubin, usually fractionated
 Gamma Glutamyl Transpeptidase (GGT)

78. Alanine Aminotransferase (ALT)/SGPT
 The test is primarily used to diagnose liver disease, to monitor the course of treatment for
hepatitis, active post-necrotic cirrhosis, and the effect of drug therapy.
 Normal value: 8-45 U/liter
 ALT is the most sensitive marker for liver cell damage.
Aspartate Aminotransferase (AST)/SGOP:
 It may be elevated other conditions such as a myocardial infarct and muscle disease
 Normal value:<25 U/L
.

79. Gamma glutamyl transpeptidase:
 Normal value:9-48 U/L
 Elevated levels of GGT : mainly alcoholic cirrhosis or individuals who are
heavy drinkers
Serum Bilirubin:
 Bilirubin is a bile pigment derived from the breakdown of Haemoglobin
 Normal value: 0.1 – 1.2 mg/100ml

80.  This is routinely performed with ‘dip-sticks’.
 It may reveal:
 Glycosuria, which may suggest diabetes mellitus
 Ketonuria, which may be a sign of diabetic ketoacidosis or starvation
 Bilirubin or urobilinogen, which may indicate hepatobiliary disorders
 Proteinuria, which may be due to menstruation, or indicate renal, urinary tract
or cardiac disease
 Haematuria, which may be due to menstruation, or indicate renal or urinary
tract disease.

81.  As markers of renal function creatinine, urea, uric acid and electrolytes are done for routine
analysis
 Serum creatinine
 Creatinine is filtered but not reabsorbed in kidney.
 Normal range is 0.8-1.3 mg/dl in men and 0.6-1 mg/dl in women.
 Not increased above normal until GFR<50 ml/min .
 Blood urea
 Many renal diseases with various glomerular, tubular, interstitial or vascular damage can
cause an increase in plasma urea concentration.
 The reference interval for serum urea of healthy adults is 10-40 mg/dl.

82.  Metabolic end product of nucleoprotein.
 Normal value:4-8.5 mg/dl for male and 2.8-7.5mg/dl for female
 Increases in gout, leukemias,lymphomas, anemia, pt on diuretics
 Evaluation of intrinsic disease of TMJ

83.  The GFR is the best measure of glomerular function.
 Normal GFR is approximately 125 mL/min
 When GFR is 5% to 10% of normal ESRD
 Inulin clearance and creatinine clearance are used to measure the
GFR.

84.  Stomatitis, gingivitis,
 A bad taste and odor in the mouth, particularly in the morning( uremic fetor), an
ammoniacal odor
 White plaques called “uremic frost” and occasionally found on the skin can be found
intraorally, although rarely.
 Significant xerostomia, probably caused by a combination of direct involvement of the
salivary glands, chemical inflammation, dehydration, and mouth breathing (kussmaul’s
respiration).

85.  Salivary function studies include:
1. Measurement of Na, K, Cl concentration in saliva
2. Measurement of total salivary flow
3. Rate of flow of saliva from orifices
4. Rate of discharge of radio-opaque dye from salivary gland following retrograde
sialography
5. Rate of uptake and secretion of 99m Tc-pertechnate by salivary glands
85

86.  Normal values for unstimulated saliva are
 K – 25 mEq/L
 Na - <10 mEq/L
 Cl - 15-18 mEq/L
 Increase in K or Na values may indicate generic inflammation or
sialodenosis
 In parotid enlargement accompanying cirrhosis
 Parotid flow rate and salivary concn of Na,K,Cl, salivary amylase & protein
increases
 Immunoglobulin levels remain normal
86

87.  In Sjogren’s Syndrome
 Flow rate is reduced
 Salivary phosphate concn is reduced
 Na & Cl concn is elevated
 Salivary IgA concn elevated
 Urea and K concn unchanged
 Abnormal protein bands can be distinguished by electrophoresis
87

89. 89

90.  Culture and sensitivity tests are used to isolate and identify causative micro
organisms of an infection
 May be obtained from blood or urine
 Particularly helpful in evaluating infections related to throat, sinuses, root
canals or bone.
 Sensitivity tests may also be ordered when patient relapses, the
identification of the organism is uncertain or the disease is severe
 Most common limitation is the delay in receiving the report
 Another problem is: in-vitro testing may not necessarily predict the same
result as in-vivo testing
90

91. 91

92.  This procedure employs the use of fluorescent labelled antibodies to
detect specific Ag-Ab reaction of known specificity in tissue sections
 When tissue sections labelled in this fashion are illuminated with ultra
violet light in an UV microscope, specific labelled tissue component can
be identified by their bright apple green fluorescence against a dark
background
92

93. 93

94. 1. ImmunoPrecipitation Assays:
Detects Antibody in solution
End point is visual flocculation of the antigen and the antibody in suspension
2. Complement Fixation:
Based on activation/fixation of complement following binding of
complement factors to Ag-Ab immune complexes
94

95. 3. Particle Agglutination:
 Relatively simple and fast
 Capable of detecting lower concentration of antibodies
 Designed to detect antibodies to viruses, subsequent to vaccination
 Utilizes Ag coated latex particles, coal particles
95

96. 4. Enzyme Immuno Assay:
 Most sensitive
 Usually indirect assay that depends on the use of anti human IgG or IgM Ab
conjugate
 Antibody conjugate, if present is made to attach to enzyme which catalyses
conversion of substrate to a coloured product which is then read by a
spectrophotometer
96

97. 5. Radio Immuno Assay:
 Extremely sensitive and specific procedure
 Used to measure concentration of Ag in patient’s sera by using Ab
 To perform this, a known quantity of Ag is made Radioactive and is made
to compete with Ag in patient’s sera for Ab binding sites
 The radioactivity of free Ag remaining is measured using a Gamma
counter
97

98.  Histopathology refers to the microscopic examination of
tissue in order to study the manifestations of the disease
 Cytopathology refers to the scientific study of role of
individual cells or cell types in disease
98

99.  A biopsy is a controlled & deliberate removal of tissue from a living organism for
the purpose of microscopic examination
 Relatively simple procedure producing little discomfort when compared to
exodontia or periodontal surgery
 Indications:
 When signs and symptoms of an observed tissue change do not provide enough
information to make a diagnosis
 When neoplasia is one of the differential diagnosis
 To confirm a clinical diagnosis
99

100.  Contraindications:
 The systemic health of the patient may contraindicate biopsy completely or at
least cause its postponement
 Site of the lesion may pose a risk to biopsy (for eg. Biopsy in richly vascularized
areas may pose a risk of haemorrhage)
 Cases of clinically obvious malignant neoplasm should be referred directly to the
appropriate specialist as biopsy would delay definitive care rather than accelerate
it
100

101.  Avoidance of Delay for Biopsy:
1. Rapid growth
2. Absent local factors
3. Fixed lymph node enlargement
4. Root resorption with loosening of teeth
5. History of malignancy
101

102.  Uses:
1. Diagnosis
2. Grading of tumours
3. Metastatic lesions
4. Recurrence
5. Management Assessment
102

103. Excisional
biopsy:
Total excision of a small
lesion for microscopic
exam.
Diagnostic +
Therapeutic
Incisional Biopsy
Performed by removing
a wedge shaped
specimen of
pathological tissue
along with surrounding
normal zone
Punch Biopsy:
With this technique the
surgical defect produced
is small and does not
require suturing
Tissue is removed in
same manner as
incisional/excisional
103

104.  The biopsy report communicates the pathologist’s opinions concerning the specimen
to the practitioner
 The format includes:
▪ Patient summary
▪ Gross description of the specimen
▪ Microscopic description of the specimen
▪ The diagnosis
▪ Additional comments
104

105.  Developed by Dr. George Papanicolaou who is also known as “Father of
cytology”
 In this, the surface of the lesion is either wiped with a sponge material or
scraped to make a smear.
 The appreciation of the fact that some cancer cells are so typical that they
can be recognized individually has allowed the development of this
diagnostic technique
105

106. Advantages:
• Time saving
• Painless
• Low cost
• No anaesthesia
• Screening test
• Rapid diagnosis
Disadvantages:
• Firm tumours
• False negative
results
• Non assessment
Indications:
• Patient
preference
• Debilitated
patients
• Adjunct
• Rapid evaluation
• Population
screening
106

107.  Interpretation:
107

108.  Microscopic examination of an aspirate obtained by inserting a
fine needle into a lesion
 Painless and safe procedure for rapid diagnosis
 Indications:
 Salivary gland pathology
 As a replacement for extensive biopsy
 Cystic lesions
 Suspicious lymph nodes
 Recurrence
 Metastatic lesion
1
0
8

109. AUTO FLUORESCENCE
 VELSCOPE
CHEMILUMINESCENCE
 VIZILITE
 MICROLUX DL
NUCLEAR MEDICINE (BONE SCAN)

116.  Lab investigations have become an integral component of a complete
examination of the patient
 They confirm the authenticity of our clinical impression and also provides
a prognostic know how post treatment
 As oral physcian we should have a thorough knowledge about different
investigations pertaining to our field of study
 We should also know how to correlate our history taking and clinical
examination so as to order for the most appropriate investigation
116

117. 1. Burket’s oral medicine, diagnosis and treatment. 8th edition.
2. Burket’s oral medicine.11th edition.
3. Textbook of ORAL MEDICINE ,Anil Govindrao Ghom, Second Edition.
4. Stern.R. Karplis, Kinney, Glickman. Using International normalized ratio to standardize
prothrombin time
5. Coleman , Nelson ; Principle of Oral Diagnosis
117