Lab investigations

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 collectionSpecimen collection Reference RangeReference Range
AccuracyAccuracy
CostCost
MorbidityMorbidity SpecificitySpecificity
SensitivitySensitivity
PrecisionPrecision
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

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. AnalyteAnalyte Normal ValuesNormal Values
Total Plasma lipidsTotal Plasma lipids 400-600 mg/dl400-600 mg/dl
Total CholesterolTotal Cholesterol 150-200 mg/dl150-200 mg/dl
HDL CholesterolHDL Cholesterol 30-70 mg/dl30-70 mg/dl
LDL CholesterolLDL Cholesterol 80-130 mg/dl80-130 mg/dl
TriglyceridesTriglycerides 50-150 mg/dl50-150 mg/dl
PhospholipidsPhospholipids 150-200 mg/dl150-200 mg/dl
Free Fatty AcidsFree Fatty Acids 10-20 mg/dl10-20 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. TestTest MaleMale FemaleFemale
CreatinineCreatinine 0.6-1.2mg/dl0.6-1.2mg/dl 0.5-1.1mg/dl0.5-1.1mg/dl
CreatinineCreatinine
ClearanceClearance
97-97-
137ml/min137ml/min
88-88-
128ml/min128ml/min
Blood UreaBlood Urea
NitrogenNitrogen
10-20mg/dl10-20mg/dl 10-20mg/dl10-20mg/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 assaysImmunoflorescent assays
DirectDirect
IndirectIndirect

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
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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
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Diseases, vol 2014.