The document provides a comprehensive overview of laboratory investigations, defining their role in clinical diagnostics and patient management. It covers various types of lab tests, their principles, and specific investigations including hematologic, endocrine, and microbiologic tests, along with their reference ranges. The conclusion emphasizes the increasing importance of laboratory methods in the prevention and monitoring of periodontal disease and its systemic implications.

1. DR. MRUDULA DEVI
I MDS

2. CONTENTS
1. INTRODUCTION
2. DEFINITION
3. CHARACTERISTICS OF A LAB
TEST
4. BASIC PRINCIPLES OF LAB
TESTS
5. TYPES OF LAB TESTS
6. INDIVIDUAL LAB
INVESTIGATIONS
7. CONCLUSION
8. REFERENCES

3. “A correct diagnosis is three fourths the remedy”
- M. Gandhi
Clinical/lab investigation data must be used to
distinguish between different diagnoses.

4. Lab Tests
• Screen for disease in asymptomatic
individuals.
• Assist in the management of patient.

5. DEFINITION
Laboratory investigations 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.

6. Key to use lab tests lies in
▪ Selection of appropriate tests
▪ Knowing the strength and weakness of tests
▪ Selecting the useful data for specific
diagnosis

7. Specimen collection Reference Range
Accuracy
Cost
Morbidity Specificity
Sensitivity
Precision
BASIC PRINCIPLES

8. The ideal diagnostic test should be
1. Highly specific, sensitive and reproducible
2. Simple to perform, rapid, one-stage or a two-stage
procedure.
3. Non-invasive.
4. Versatile
5. Amenable to chair-side use.
6. Economical.

9. TYPES OF INVESTIGATIONS
Based on where the investigation is done
Chair Side Investigations
Laboratory based Investigations

10. Laboratory based investigations
 Haematologic
 Endocrine
 Hepatobiliary
 Renal
 Bone
 Immunologic

11. HAEMATOLOGICAL INVESTIGATIONS

12. SAMPLE COLLECTION
‣ Skin Puncture
‣ Venipuncture
‣ Arterial blood

13. COMPLETE BLOOD PICTURE (CBP)
a. HAEMOGLOBIN ESTIMATION
Haemoglobin Normal Values (g%)
Men 13 – 17
Women 11.5 – 14.5
Children (upto 1 year) 11.0 – 13.0
Children (10-12 years) 11.5 – 14.5
Infants (full term cord
blood)
13.5 – 19.5

14. Haematocrit (HCT)/Packed Cell Volume(PCV)
Vol of RBCs : Total Blood - Males - 42-52%
Females – 37-47%

15. b. RED BLOOD CELL INDICES
i) RBC Count
Male : 4.5-6.0 million/mm3
Female: 4.0-4.5 million/mm3
ii) MCV – HCT/RBC : 80-100 fL
iii) MCH – Hb/RBC : 27-31 pg/cell
iv) MCHC – Hb/HCT : 32-36 g/dL
v) RCDW – 11.5-14.5%

16. vi) Erythrocyte Sedimentation Rate (ESR)
Westergren’s method: Males: 0-10mm/hour
Females: 0-20mm/hour
Wintrobe’s method: Males: 0-7 mm/hour
Females: 0-14mm/hour

17. C. WHITE BLOOD CELL INVESTIGATIONS
i) Total Leucocyte Count :
Adults :
4,000 – 11,000 / cu.mm (µl).
At birth :
10,000 – 25,000 /cu.mm (µl).

18. ii) Differential Leucocyte Count:
Neutrophils 40 – 75% 3000-7000/cu. mm
Basophils 0 – 1% 0-100/cu. mm
Eosinophils 1-4% 50-300/cu. mm
Monocytes 2- 8% 100-600/cu. mm
Lymphocytes 20 – 45% 1000-3500/cu. mm

19. d. PLATELET INDICES

20. Tests for defects in blood clotting and bleeding
1) Bleeding Time
Duke’s method :
Normal Range : 1-5 minutes.
Ivy method:
Normal Range : 5-11 minutes.

21. 2) Clotting Time
Capillary Method :
4 to 9 minutes.
3) Prothrombin time
Normal PT range : 10-14sec.
4) Partial Thromboplastin Time
Normal PTT range - 60-80 sec
aPTT range - 30-45 sec

22. International Normalized Ratio
(INR)
Ratio of a patient's prothrombin time to a
normal (control) sample, raised to the power of
the ISI value for the analytical system being
used.
Healthy <1.1
Patients under Warfarin : 2.0-3.0

23. INR RATIO AND ITS SIGNIFICANCE
Treatment Safe Borderline Adjustment
Prophylaxis <3.5 >3.5
Scaling & Root
Planing
<2.5 2.5-3.5 >3.5
Extraction <2.5 2.5-3.5 >3.5
Gingivoplasty <2.5 2.5-3.5 >3.5
Multiple
Extraction
<2.5 2.5-3.5 >3.5
Gingivectomy <1.5 1.5-2.5 >2.5
Minor Flap <1.5 1.5-2.5 >2.5
Full Arch Extns >1.5 >1.5
Extensive Flap <1.5 >1.5

24. UREA AND ELECTROLYTES
a. Sodium : 136-145 mEq/L
b. Potassium : 3.5 to 5.2 mEq/L
c. Chloride : 95 to 108 mEq/L
d. Urea : 1.8-8.2 mEq/L
e. Bicarbonates : 24 to 30 mEq/L

25. PLASMA PROTEINS
Total Protein - 6.0 to 7.8 g / 100 ml.
• Albumin - 3.2 to 5.6 g / 100 ml
• Globulin - 2.3 to 3.5 g / 100 ml
• Fibrinogen – 0.3 gm/100 ml
• A/G ratio - 1.5:1 to 2.5:1

26. Analyte Normal Values
Total Plasma lipids 400-600 mg/dl
Total Cholesterol 150-200 mg/dl
HDL Cholesterol 30-70 mg/dl
LDL Cholesterol 80-130 mg/dl
Triglycerides 50-150 mg/dl
Phospholipids 150-200 mg/dl
Free Fatty Acids 10-20 mg/dl
PLASMA LIPID PROFILE

27. MICRO NUTRIENTS
Calcium : 9-11 mg/dL
Phosphorus : 2.5-4.5 mg/dL
Iron : 55-160 µgm/dL
Copper : 63-140 µgm/dL
Zinc : 0.66-1.10 µgm/dL
Magnesium : 1.5-2.5 mEq/L

28. ENDOCRINE INVESTIGATIONS

29. DIABETES
i) Fasting plasma glucose
– Normal range: 70-100mg/dl
–Diabetes mellitus : >126mg/dl
–Hypoglycemia : <50mg/dl in males ;
<40mg/dl in females

30. ii) Post prandial blood glucose
Normal: <140mg/dL
iii) Random blood glucose
Normal range : 79-160 mg/dL
iv) Oral Glucose Tolerance Test (OGTT)
– Fasting: <105mg/dl
– After 1 hour: <190mg/dl
– After 2 hours: <165mg/dl
– After 3 hours: <145mg/dl

31. v) Glycated Haemoglobin

32. KETONE BODIES
i. Acetone
ii. Acetoacetate
iii. Beta Hydroxy Butyrate
Normal Conc. in blood : 1mg/dL

33. THYROID
Thyroid hormones
T3 (Triiodothyronine)
T4 (Thyroxine)
TSH (Thyroid Stimulating Hormone)

34. Thyroid Function Tests
Test Range
TSH 0.5-4.7 mU/l
T3 0.92-2.78 nmol/L
FT3 0.22-6.78 pmol/L
T4 58-140 nmol/L
FT4 10.3-35 pmol/L

35. HEPATOBILIARY INVESTIGATIONS

36. LIVER FUNCTION TESTS
Bilirubin : 0.1 to 1.2 mg / 100 ml.
Alanine aminotransferase : 3– 26 IU/ L
Asparate aminotransferase : 6 -25 IU/ L

37. Alkaline phosphatase :
King Armstrong Units: 4 to 13
Brodansky Units: 1.5 to 4.5
International Units: 30 to 85 IU
Gamma glutamyl transferase : 9-48 IU/L
5’- Nucleotidase : 2-15 IU/L

38. RENAL INVESTIGATIONS

39. Test Male Female
Creatinine 0.6-1.2mg/dl 0.5-1.1mg/dl
Creatinine
Clearance
97-
137ml/min
88-
128ml/min
Blood Urea
Nitrogen
10-20mg/dl 10-20mg/dl
RENAL FUNCTION TESTS

40. BONE INVESTIGATIONS

41. Routine Bone Profile:
Calcium – 9-11 mg/dL
Phosphate - 2.5 to 4.5 mg/dL
Albumin - 3.5 to 5.5 g / dL
Alkaline phosphatase – 30-85 IU/L

42. IMMUNOLOGIC INVESTIGATIONS

43. C – Reactive Protein
Normal serum conc.
5 - 10 mg/L
Methods of assessment :
ELISA
IFA
Laser Nephelometry

44. AIDS Serology
Lymphocyte Immuno-phenotyping
T cells - 800-2500/ µL.
CD4 Cells - 600-1500/µL.
CD8 Cells - 300-1000/ µL.
CD4 : CD8 – 2 ( <1 in HIV)

45. MICROBIOLOGIC TESTS
Bacterial Culturing
Dark-field Microscopy

46. Immunodiagnostic Methods
Immunoflorescent assays
Direct
Indirect

47. ii) Flow Cytometry
iii) ELISA
Evalusite

48. iv) Latex Agglutination

49. Enzymatic Methods
BANA Test
Perioscan

50. Molecular Biology Techniques
i) Nucleic Acid Probes
Omnigene

51. DNA-DNA Hybridization
a. FISH
b. Checkerboard
c. Reverse Capture

52. Polymerase Chain Reaction
a. Single target
b. Multiplex
c. Real Time

53. Other Biochemical test kits :
Periocheck
Prognostik
Biolase
Pocket watch
TOPAS

54. Recent Diagnostic Kits :
OFNASET
Electronic taste chips
IMPOD
Salimeterics

55. GENETIC TEST KIT
PST Genetic Susceptibility Test

56. Increased Decreased
ESR,
WBC count and DLC
Platelets and its indices
Globulin
Fibrinogen
Total cholesterol and LDL
Copper
ALP
SGPT
Gamma glutamyl transferase
C-Reactive Protein
Hb, Haematocrit
Red cell count and its indices
Albumin
A/G ratio
Iron
Zinc
Calcium
To summarize..

57. CONCLUSION
The transfer of diagnostic methods from
laboratory to clinical use is increasingly used
in the prevention and monitoring of the
exacerbation and treatment of periodontal
disease, as well as of its impact on systemic
disease.

58. REFERENCES
1. A Mariotti. Laboratory testing of patients with systemic
conditions in periodontal practice. Perio 2000, vol 34, 2004,
84-108.
2. Joseph J. Zambon & Violet I. Haraszthy. The laboratory
diagnosis of periodontal infections. Perio 2000, Vol. 7, 1995,
69-82
3. K.D. Pagana. Mosby’s Diagnostic and Laboratory test
reference, 2015, 12th Ed
4. N.A. Ghallab. Archives of Oral Biology (2018) 115–124

59. 5. Sachin M. Chairside diagnostic test kits in Periodontics – A
Review. Int Arab J Dent, 2012
6. Shivraj G etal. A review on laboratory liver function tests. Pan
Afr Med J. 2009; 3-17
7. T Bansal etal. CRP and Periodontal Disease. J Clin and Diag Res.
2014 Jul, Vol-8(7): 21-24
8. V Grover etal. Clinical relevance of the advanced microbiologic
and biochemical investigations in periodontal diagnosis, J Oral
Diseases, vol 2014.