Lab investigations in OMFS- ih

2. P R E S E N T E R - D R . I T R A T H U S S A I N
M O D E R A T O R – D R . A L O K B H A T N A G A R
LABORATORY INVESTIGATIONS
IN OMFS

3. INTRODUCTION
 Laboratory Tests include any test or
examination of materials derived from the
human body for the purpose of making
patient care decisions and improving
public health.
 laboratory measurements form the scientific basis
upon which medical diagnosis and management of
patients is established.

4. Laboratory tests required in oral surgical procedures
1. Blood studies
2. Biochemical
3. Histopathological
4. Immunological tests
5. Microbial

5. HAEMATOLOGY
 Is the branch of internal medicine, physiology,
pathology, clinical laboratory work, and pediatrics
that is concerned with the study of blood, the blood-
forming organs, and blood diseases.
 Hematology includes the study of etiology, diagnosis,
treatment, prognosis, and prevention of blood
diseases.

6. Haematological investigations
 Hb concentration.
 Red cell count (RCC).
 MCV.
 MCH.
 MCHC.
 Haematocrit (Hct) or PCV.
 White cell count.
 WBC differential.
 Platelet count
 ESR

7. Haemoglobin
 Normal: Women:12.0-16.0g/dl
Men: 14.0-17.4 g/dl
anemia states,
thalassemia,
hemoglobinopathie
s
Liver disease,
hypothyroidism
Hemorrhage(chroni
c or acute)
DECREASED
IN
Polycythemia vera
COPD
Congestive heart
failure
INCREASED
IN
high altitude = Hb
Excessive fluid intake
= Hb
pregnancy
INTERFER
ING
FACTORS

8. RED BLOOD CELL COUNT
 The RCC is an important measurement in the
evaluation of anemia or polycythemias and
determines the total number of erythrocytes per ml
of blood.
 Reference Values
 Men: 4.2-5.4x 106/mm3
 Women: 3.6-5.0 x 106/mm3

9.  Decreased counts:
Anemias
Disorders such as:
Hodgkins disease and lymphomas
Rheumatic fever
SABE
 Erythrocytosis- Increased count:
Polycythemis vera
Renal disease
Extrarenal tumors
High altitude
Pulmonary disease
Cardiovascular disease
Hemoglobinopathy

10. Red Blood Cell Abnormalities Seen on Stained
Smear
 Anisocytosis - Variability of cell size . pernicious anaemia
 Leptocytosis - Hypochromic cells with central zone of Hgb (“target
cells”) Thalassemias , Obstructive jaundice
 Schistocytosis - MCHC high, Accelerated red blood cell
destruction .
 Acanthocytosis - Presence of cell fragments in Circulation ,
Increased intravascular mechanical trauma .
 Echinocytosis - Irregularly spiculated surface , Irreversibly
abnormal membrane lipid content , Liver disease.
 Elliptocytosis - Oval cells , Hereditary anomaly, usually harmless .

11.  Macrocytosis - Megaloblastic anemias , Severe liver disease,
Hypothyroidism
 Microcytosis - Iron-deficiency anemia ,Thalassemias
 Hypochromia - Increased zone of central pallor , Diminished Hgb
content
 Hyperchromia -Microcytic, hyperchromic cells, Increased bone marrow
stores of Iron
 Polychromatophilia -Presence of red cells not fully Hemoglobinized ;
Reticulocytosis
 Poikilocytosis - Variability of cell shape ; Sickle cell disease, Leukemias

12. Hematocrit (PCV)
Normal
 Men: 40-50%
 Women: 37-47%
 Decreased Hct
 Leukiemias
 Adrenal insufficiency
 Chronic disease
 Acute and chronic blood loss
 Hemolytic reaction
Increase values:
 Erythrocytosis
 Polycythemis Vera
 Shock

13. Red Blood Cell Indices
 MCV,MCHC and MCH
 They are used to differentiate anemias and when
they are used together with peripheral smear give a
clear picture of the RBC morphology.

14. MCV
 This index expresses the volume occupied by a single
RBC
 Refrence Values
 Normal:
 80-100 fl
 Decreased MCV- iron defeciency anemia, β-
thalassemia trait, sideroblastic anemia.
 Increased -Megaloblastic anemia,Myelodysplasia

15. MCH
 average weight of Hb per RBC.
 This index is of value in diagnosing severely anemic
patients.
 Refrence Values
 Normal 26-34 pg/cell
 Clinical Implications
 An increase in the MCH is associated with
macrocytic anemias and newborns
 A decrease is associated with microcytic anemia

16. Mean Corpuscular Hemoglobin Concentration
(MCHC)
 Monitoring the therapy for anemia.
 Normal
 32-36 %
 CLINICAL IMPLICATIONS
 Decreased MCHC values signify that a unit volume of
packed RBC contains less Hb than normal
 Hypochromic anemias <30g/dl occurs in:
Iron deficiency
Microcytic anemias,chronic blood loss anemias
 Increased MCHC values occur in :
 Spherocytosis
 Newborns and infants

17. Total Leukocyte Count
 WBC serve as a useful guide to the severity of the disease
process.It calculates total number of leukocytes per mm3
of blood
 Normal
 Adults 4.5-10.5x 103 cells/mm3
 Children:
 2 months – 6 years: 5.0-21.0x103 cells/mm3
 6-18 years: 4.8-10.8x 103 cells/mm3

18. Leukocytosis: WBC > 11000/mm3
 Usually caused by an increase of one type of cell and an increase is
rarely caused by a proportional increase of all cell types.
 Leukaemoid Reaction
 Acute infections: degree of increase depends on severity of infection,
patients resistance, age, marrow efficiency and reserves.
 Other causes:
 Leukemia
 Trauma
 Malignant neoplasms
 Hemolysis,Hemorrhage
 Tissue Necrosis

19. Leukopenia WBC < 4000/mm3
 Viral infections,some bacterial infections
 Hypersplenism
 Bone marrow depression caused by heavy metal
intoxication,drugs,ionizing radiation
 Pimary bone marrow disorders:Leukemias,Pernicious
anemia,aplastic anemia
 Immune associate
INTERFERING FACTORS
 Age
 Stress

20. Differential Leukocyte Count
 The total count of circulating WBC is differentiated
according to 5 types of leukocytes,each of which
performs specific function expressed as a % of total
WBC.

21. Neutrophils
 Neutrophils constitue a primary defense against
microbial infection through a process known as
phagocytosis..
 Neutrophilia- increase in absolute no. of neutrophils
 Neutropenia- decrease in the absolute no.
 Refrence values
 Normal absolute count- 3000-7000 cells/mm 3
 Differential- 50 % of total WBC

22. Neutrophilia: >8x 109 /L
 Acute/Localized/gen/ bacterial infections, fungal
and spirochetal infections
 Inflammation and tissue necrosis
 Metabolic intoxication
 Chemical and drugs
 Acute hemorrhage, hemolytic anemia,transfusion
reactions
 Myeloproliferative disease
 Malignant neoplasms

23. Neutropenia <1.8x10 9/l
 A) decreased or ineffective production
Stem cell disorders
Acute infections
Viral infections
Malaria
Drugs,chemicals,ionizing radiation
B) decreased survival
low marrow reserve,infants,elderley
Autoimmune causes
Drug hypersensitivity
Pregnancy

24. Common Medicinal Causes of
Neutropenia
 Cytotoxic agents
 Antibiotics (Penicillins, Cephalosporins,
Sulfonamides)
 Anticonvulsants
 NSAIDs
 Antithyroid agents (Methimazole, PTU)
 Phenothiazines
 Cimetidine

25. Eosinophils
 Capable of phagocytosis,ingest Ag-Ab complexes and become active in later
stages of inflammation
 Used to diagnose allergic states,
 Assess severity of infestation with worms and large parasite and monitor
Rx.
 Refrence Values
 Normal: Absoluute: 0-0.7x109/l
Diff: 0%-3% of total WBC
CLINICAL IMPLICATIONS
Eosinophilia: > 5% or >500 cells/mm3
Allergies, asthma
Parasitic disease
Chronic skin disease- pemphigus,eczema,dermatitis herpetiforms
Allergic drug reactions

26. Eosinopenia:
 Usually caused by increased adrenal steroid
production associated with
A. Cushing Syndrome
B. use of certain drugs
INTERFERING FACTORS
Normal count lowest in mornings, highest from noon
till after midnight so repeated at same time each day.

27. Basophils
 Phagocytic,used to study chronic inflammation
 Refrence Values
 Normal: Absolute:15-50/mm3
 Differential: 0%-1% of total count
 Clinical Implications
 Basophilia >50/ mm
 Granulocytic leukemia
 Acute basophilic leukemia
 Acute phase of infection
 Hyperthyroidism
 Prolonged steroid therapy

28. Monocytes
 Largest cell,second line of defense against infection;scavenger
action;produce antiviral agent interferon
 Reference values
 Normal: Absolute: 100-500 /mm3
 Differntial: 3-7% of total wbc
CLINICAL IMPLICATIONS
Monocytosis >500 cells/,mm
bacterial infection sabe,
syphilis
Ca breast, stomach
hodgkins disease
Monocytopenia <100 cells/ mm
Predisone Rx
Hairy cell leukemia
HIV

29. Lymphocytes
 Lymphocytosis adults> 4000/mm3
 children > 7200/mm3
 Lymphatic leukemia
 Infectious lymphocytosis
 Infectious mononucleousis- atypical lymphocytes
 Other viral diseases
 Cytomegalovirus
 Measles ,mumps,chickenpox
 HIV infection
 Infectious hepatitis

30.  Lymphocytopenia: adult<1000 cells/mm3
children < 2500 cellls /mm3
 Chemotherapy,radiation,immunosupressive
medication
 Increased loss through GIT
 Aplastic anemia
 Hodgkins lymphoma
 AIDS
 Rheumatoid arthritis, SLE

31. Some WBC abnormalities
 Atypical lymphocytes Infectious mononucleosis, any viral
infection,toxoplasmosis, drug reactions.
 Auer rods Seen in myeloblasts; pathognomonic of
AML.Prominent in AML M3 subtype (acute promyelocytic
leukaemia).
 Left shifted Immature WBCs seen in peripheral blood. Seen
in severe infections, inflammatory disorders, marrow ‘stress’,
CML.
 Right shifted Hypermature WBCs seen in peripheral
bloode.g. megaloblastic anaemia and iron deficiency.

32.  Toxic granulation: Coarse granules in
neutrophils. Seen in severe infection, post-
operatively and inflammatory disorders.

33. PLATELET COUNT
 As a screening tests for the disorders of platelet function
 both congenital and acquired and for Willebrand’s disease
 Bleeding time
 Normal range:
 Duke’s method: 3 ½ minute with a value of 4 min or more
being definitely abnormal
 Ivy method: Normal range upto 11 minutes most normal
people cease bleeding within 7 minutes
 Increased:
 I.T.P. - > Due to lack of platelets
 Secondary Thrombocytopenia
Acute leukemias
Aplastic Anemias
Septicemia

34. BLEEDING TIME
 Range – 2–10 minutes
 This is a test of platelet function, not a test of
coagulation factors.
 ↑ Platelet disorders, thrombocytopenia, thrombasthenia
. Drugs: aspirin and other preparations containing
aspirin.
 Test is useful as a screening test (with aspirin challenge)
for diagnosis of von Willebrand’s disease and platelet
disorders.

35. CLOTTING TIME
 It is the time taken by blood to coagulate after it has been
shed.
 Wright’s capillary tube method - Normal – 1-3 minutes
 Lee and whites method – Normal – 5 to 11 minutes at 370
 INCREASED IN
 In hemophelia, (due to the lack of the antihemophilic
globulin ) – may be upto 60mts or more.
 In liver disease - when liver is unable to synthesize factor
II, V, VII, X
 In hereditary
 In von willebrand’s disease
 Occasionally in leukemia
 Acute febrile conditions.

36. Conditions where CT is reduced
 In typhoid
 In endocarditis
 After meal
 After hemorrhage
 After Splenectomy
 After GA
 Digitalis Therapy

37. Prothrombin time (PT)
 The prothrombin time (PT) and its derived measures
of international normalized ratio (INR) are measures
of the extrinsic pathway of coagulation.
 The INR is the ratio of a patients prothrombin time
to a normal (control)sample, raised to the power of
the ISI value for the analytical system used.
 The reference range for prothrombin time is usually
around 11–16 seconds (70% - 100%)
 The normal range for the INR is 0.8–1.2

38.  INR for those receiving therapeutic anticoagulation
therapy is 2.0 to 3.0.
 For those with mechanical prosthetic heart valves, an
INR of 2.5 to 3.5 is suggested
 Prolonged PT/INR
• Warfarin / heparin therapy
• Liver diseases
• Malabsorption of Vit. K
• DIC
• Haemorrhagic diseases of new born

39. Activated partial thromboplastin time (aPTT or
APTT)
 Is a performance indicator measuring the efficacy of both
the "intrinsic" (now referred to as the contact activation
pathway) and the common coagulation pathways
 Normal:Partial thromboplastin time (PTT): 30 - 45
seconds
 Prolonged APTT
 Haemophilia
 Von Willibrand disease
 Warfarin/heparin therapy
 Liver diseases
 DIC

40. THROMBIN TIME
 Range – 24–35 seconds
 Physiologic Basis – Prolongation of the thrombin time indicates
a defect in conversion of fibrinogen to fibrin
 Increase: Low fibrinogen , abnormal fibrinogen
(dysfibrinogenemia), increased fibrin degradation products
(egDIC), heparin, fibrinolytic agents (streptokinase, urokinase,
tissue plasminogen activator), primary systemic amyloidosis
 Thrombin time can be used to monitor fibrinolytic therapy and to
screen for circulating anticoagulants.

41. Factor eight assay
 Range – 40–150% of normal
 Physiologic Basis – Measures activity of factor VIII
 Interpretation - ↑ Inflammatory states (acute phase
reactant), last trimester of pregnancy, oral
contraceptives.
↓Hemophilia A , von Willebrand’s disease,DIC
 Comments – Normal haemostasis requires at least
25% of factor VIII activity. Symptomatic hemophiliacs
usually have levels ≤5%

42. BLOOD CHEMISTRY
 Electrolyte panel Na,K,Cl,Ca,CO2,pH
 Kidney function BUN, Creatinine,,uric acid
 Lipids Cholesterol,triglycerides,LDL,HDL
 Liver function Total biliribin, alkaline phosphatase
GGT,Total protein,A/G ratio,Albumin,
AST,ALT
 Thyroid Function T3 uptake,free T3, T4, Total T3,T4,TSH
 Diabetes Panel Blood sugar(Fasting,PP,Random)GTT,
HbA1c

43. ELECTROLYTES
Sodium(Na)
 Detects changes in the water balance,acid-base balance and assess
dehydration and water intoxication.
 Reference values:
 Normal
 Adults: 136-145 mEq/L
 CLINICAL IMPLICATIONS
=> HYPONATREMIA
 Severe burns Severe Nephritis
 CHF Diabetic acidosis
 Fluid loss Diuretics
 Addisons disease water intoxication

44. HYPERNATREMIAA
 Dehydration and insufficient water intake
 Conns disease
 Primary aldosteronism
 Cushing disease
 Diabetes insipidus

45. Potassium
 Plays role in nerve conduction,muscle function,acid-
base balance and osmotic pressure,rate and force of
heart contraction and C.O
 REFERENCE VALUES
Normal
 Adults: 3.5-5.2mEq/L
 Children 3.4-4.7mEq/L

46.  Hypokalemia Hyperkalemia
 Diarrhea,vomiting,sweating Renal Failure
 Starvation,malabsorption
Burns,accidents,chemo,Surgery
 Drainig wounds, Metabolic acidosis
 Cystic fibrosis Addisons disease
 Severe burns Uncontrolled
diabetes
 Alcoholism Arrhythmias
 Respiratory alkalosis Sinus brachycardia
 Diuretic,mineralocorticoid Sinus arrest

47. Calcium
 Measures the concentration of total and ionized calcium in blood
 Reflects parathyroid and calcitonin function
 Reference values
 Normal
 Adult 9-11 mg/dl
 CLINICAL IMPLICATION
 Hypercalcemia >12mg/dl Hypocalcemia
 hyperparathyroidism
 Cancer (PTH producing tumor) hypoparathyroidism
 Thyroid toxicosis hyperphosphatemia
 Pagets disease malabsorption
 Vit D intake excess osteomalacia
vit D deficiency

48. Phosphorous
 Evaluated with calcium as inversely proportional to ca
 Reference
 Adult 2.7-4.5 mg/dl
 Children 4.5-5.5 mg/dl
 CLINICAL IMPLICATIONS
 Increased levels Decreased levels
 Kidney dysfunction,uremia hypoparathyroidism
 Renal insufficiency Rickets
 Nephritis Diabetic coma
 Hypoparathyroidism liver disease
 Hypocalcemia vomiting,diarrhoea
 Bone tumors gram –ve septecemia

49. KIDNEY FUNCTION
TESTS

50. BUN(Blood Urea Nitrogen)
 Final product of protein metabolism
 Amount of urea excreted varies with diet protein intake
 Measures nitrogen portion of urea
 Index of glomerular function
 Refrence range = 6-20 mg/dl
 CLINICAL IMPLICATIONS
 Increased BUN”(Azotemia) Decreased levels:
 Impaired renal function- liver failure
 CHF, salt + water depletion, Acromegaly
Shock, stress ,acute MI Malnutrition
 Chronic renal disease Impaired absorption
 U.T obstructiion
 D.M
 Anabolic steroid

51. Creatinine
 Byproduct in muscle breakdown
 Excreted by kidney
 Helps in diagnoses of impaired renal function
 Reference
 Normal
 Adult
 Men: 0.9-1.3 mg/dl
 Women-0.6-1.1 mg/dl

52.  INCREASED DECREASED
 Impaired renal function Muscle mass
 Chronic nephritis advanced liver disease
 Obstruction of U.T diet protein
 Muscle diseases Pregnancy
Gigantism
Acromegaly
Mysthenia gravis
Poliomyelitis
Muscular dystrophy
 CHF
 Shock
 Dehydration

53. Uric acid
 Breakdown of nucleonic acid
 Product of purine metabolism
 Basis of test: overproduction occurs when:
• Extreme cell breakdowm
• Production and destruction of cells
• Inability to excrete; evaluates: Renal failure
 Gout
 Leukemia
 Reference
 Normal
 Men 3.4-7.0 mg/dl
 Women 2.4-6.0 mg/dl

54. Hyperuricemia Decreased
levels
 Renal disease Fancons syndrome
 Gout malignancies -Hodgkins
 Alcoholism
 Downs syndrome
 Leasd poisoning
 Luekemia lymphoma
 Metabolicacidosis
 Liver disease
 Hemolytic anemia
 Chemo and radiation

55. Liver function tests

56. Bilirubin
 Results from breakdown of Hb in RBC and is a byproduct
of hemolysis.
 Excreted into bile by liver
> indirect(unconjugated, protein bound)
> direct (conjugated, free)
 Allows evaluation for liver function and hemolytic
anemias
 Reference
 Normal
 Total 0.3-1.0 mg/dl
 Conjugated 0.0-0.2mg/dl

57.  Total increase accompanied by jaundice due to either hepatic,obstructive or
hemolytic causes
 Hepatocellular jaundice
o Viral
o Cirrhosis
o Infectious mononucleosus
 Obstructive
o Increased conjugated biliribin
 Hemolytic (Increased unconjugated)
o Blood transfusion
o Sickle cell anemia
o Transfusion reaction

58.  Increase in indirect
• Hemolytic anemia
• Trauma
• Gilbert syndrome
 Increase in direct bilirubin
• Cancer of pancreas
• Dubin johnsons

59. AST/SGOT
 Enzyme present in tissues of increased metabolic
activity like heart, liver, skeletal muscle, kidney,
brain, pancreas, spleen and lungs
 Released into circulation following injury or cell
death
 So any damage in these tissues-- increase in AST
 Reference
 Normal
 6-25 IU/l

60.  Increases Decreases
 In MI chronic renal diseases
 In Liver damage vitamin B6 deficiency
 Acute hepatitis
 Chronic hepatitis
 Cirrhosis
 Hepatic necrosis
 Primary Ca.
 Alcoholic hepatitis
 Others:
 Hypothyrodism
 Trauma of skeletal muscle
 Toxic shock syndrome

61. ALT/SGPT
 Increased concentration in liver,relatively low in
heart,muscle and kidney
 Primary to diagnose liver diseases and monitoring
Rx
 Reference
 Normal
 3-26 IU/L

62.  Increases
 Hepatocellular jaundice
 Alcoholic cirrhosis
 Metastatic liver tumor
 Obstructive jaundice
 Viral,infectious,toxic hepatitis
 MI,heart failure
 AST/ALT comparision
 AST always increases in acute MI,ALT does not unless liver
damage
 ALT increased > AST in acute extrahepatic biliary obstruction
 ALT more specific to liver disease

63. Alkaline phosphatase
 Enzyme originating in bone,liver
 Used as an index of liver and bone disease
 Refrence values
 Normal
 Males 1-12 yrs < 350 u/l
 12-14 <500 u/l
 >20 yrs 25-100 u/l
 Females 1-12 yrs <350 u/l
 >15 25-100 u/l

64.  INCREASES in
 Liver Diseases OTHER DISEASES
 Obstructive Jaundice hyperparathyroid
 Space Occupying Lesions Of Liver hyperthyroidism
 Hepatocellular cirrhosis hodgkins disease
 Biliary cirrhosis Ca liver, pancreas
 Intra and extra hepatic cholestasis DECREASES IN
 Hepatitis congenital
 DM malnutrition
 Bone diseases hypothyroidism
 Pagets disease anemias
 Metastatic bone tumors
 Osteogenic sarcoma
 Osteomalacia
 Rickets

65. Albumin
 Buffer function
 Reference
 Normal
 Adult -3.5-5.2 g/dl
 CLINICAL IMPLICATIONS
 Decreases
 Acute and chronic inflammation,infections
 Cirrhosis ,liver disease,alcoholism,
 Burns
 Starvation,malnutrition
 Thyroid diseases

66. TEST FOR DIABETES

67. Fasting blood glucose
 Refrence values
 Normal
 FBG <110mg/dl
 CLINICAL IMPLICATIONS
 Increased Decreased
 DM
 fasting > 126mg/dl Pancreatic islet cell Ca
 PP >200 mg/dl
 OGTT 140–199 mg/dl addisons disease
 Other hypopituitarism,hypothyroid
 Cushing disease starvation, malabsorption
Acute stress liver damage
 Pheochromocytoma
 Pituitary adenoma
 Pancreatitis
 Adcanced liver disease

68. Hemoglobin A1c Test
 The hemoglobin A1c test, also called HbA1c, glycated
hemoglobin test, or glycohemoglobin, is an important
blood test that shows how well diabetes is being
controlled.
 Hemoglobin A1c provides an average of your blood sugar
control over the past 2 to 3 months
 used along with home blood sugar monitoring to make
adjustments in diabetes medicines. ,
 normal range = 4% -5.6%.
 levels between 5.7% and 6.4% indicate increased risk of
diabetes.
 levels of 6.5% or higher indicate uncontrolled diabetes

69. LIPID PROFILE
 Cholesterol
 Hdl
 Ldl
 Triglycerides

70. Cholesterol
 Evaluates the risk for atherosclerosis,myocardial
occlusion,and coronary artery occlusion.
 Relates to CHD, screening test
 Also part of liver function,renal function and DM studies
 Reference values
 Normal
 Adults fasting
 Desirable 140-199mg/dl
 Borderline high-200-239 mg/dl
 High >240 mg/dl

71.  Basis for classifying CHD risk
 Levels >240mg/dl high risk
 Hypercholesterolemia Hypocholesterolemia
 Type II familial hypercholestrolemia Hypolipoproteinemia
 Cholestasis Myeloproliferative
disease
 Hepatocellular disease Hyperthyroidism
 Nephrotic syndrome Malabsorption
 Chronic renal failure
 Hypthyroidism
 Pancreatic neoplasms
 Poorly controlled DM
 Diet
 Obesity

72.  Overnight fasting recommended
 Alcohol abstain 48 hrs before test

73. HDL
 Class Of Lipoprotein Produced By Liver And
Intestine
 Cholesterol Balance-removes It From Arteries
 INCREASED LEVELS- CARDIOPROTECTIVE
 Reference values
 Normal
 Men 35-65 mg/dl
 Women: 35-80 mg/dl

74.  Increased values
 Familial hyperlipoproteinemia
 Chronic liver disease
 Long term aerobic exercise
 Decreased values
 Familial hyplipoproteinemia
 Hypertriglyceridemia
 DM
 Hepatocellular diseases
 Cholestasis

75.  Increased levels:Estrogen therapy,alcohol,insulin
therapy
 Decreased levels:
steroids,antihypertensives,diuretics, stress,obesity
,smoking
 8-12 hour fast recommended
 Avoid alcohol consumption 24 hrs
 Withhold medication 24 hrs

76. LDL / VLDL
 70% of total serum cholesterol present in LDL
 Cholesterol rich remnants of VLDL lipid transport
vehicle
 Test done to determine CHD risk
 Reference values
 Adults
 Desirable <130 mg/dl
 Borderline 140-159 mg/dl
 High risk >160 mg/dl

77. Clinical Implications
 INCREASED Ldl Decreased
 Familial Hypercholeterolemia hypolipoproteinemia
 Secondary Causes Type I
 Diet hyperthyroidism
 Hyperlipidemia Secndary
to hypothyroidism
 Nephrotic syndrome
 multiple myelomas
 DM
 Porphyria

78. Triglycerides
 Account for >90% of dietary fat intake and 95% of stored
fat
 Main plasma glycerol ester
 Test evaluates suspected atherosclerosis and body’s
ability to metabolise fat
 Reference values
 Normal
 Desirable <150mg/dl
 Borderline 150-199mg/dl
 High 200-499mg/dl
 Very high> 500mg/dl

79.  Increased levels
 Hyperlipoproteinemia
 Liver disease , alcoholism
 Nephrotic syndrome
 Hypothyroidism
 DM
 Pancreatitis
 Glycogen storage disease
 Decrease levels
 Congenital lipoproteinemia
 Malnutrition’
 Hyperthyroidism

80. Immunological Studies
 Syphilis
 HIV Blood Group
Rh Typing
Coomb’s Antiglobulin Test
 Hepatitis
 HSV
 EBV
 Candida antibody test

81. MICROBIOLOGICAL STUDIES
 Microbiology is a broad term which includes
virology, mycology, parasitology, bacteriology,
immunology and other branches.

84. Syphilis Detection Test
 Venereal disease – Caused by treponema pallidum
 Ab to syphilis begin to appear 4-6 weeks after infection.
 Non-treponemal test- presence of reagin which is a non-
treponemal auto-antibody directed against cardiolipin
antigens.
 SCREENING TESTS
 Specific tests detect antibodies to T.Pallidum- Confirmatory
 Passive particle agglutination T.Pallidum test.(TP-TA)
 Fluorescent treponemal antibody absorption test (FTA-ABS)
 Reference value
 NORMAL-nonreactive, negative for syphilis

85.  Diagnosis- Correlation of history, physical and result of
confirmatory test.
 Confirm-with both screening + confirmatory is reactive
 If negative-
 Patient does not have syphilis
 Too recent infection, repeat at 1 week, 1 month & 3month interval
 Latent /Inactive phase
 Faulty immunodefense mechanism
 False Positive False –ve
 drug abuse early in disease course
 LE during inactive or later stages
 Recent immunnization
 leprosy

86. HIV
 Detec HIV virus type 1 and 2.
 used to determine the presence of antibodies to
HIV-1
 include ELISA, western blot & PCR.
 Single reactive ELISA – repeated in duplicate
 If repeatedly reactive – follow up western blot
 If positive– confirmatory
 HIV-1/2- also to screen blood + by products for
transfusion and organ transplant donors

87.  Whom to test How to test
 IV drug users Screening enzyme immuno assay &
confirmatory test
 People engaging in unprotected sex W.B detects antibodies to HIV-1
coreantigens:-
gp1, , p18, p24, p31, p40,
p65, p55/51
 Pregnant women IFA confirmatory test detects
potent ab’s by
fluoroscense tagged secondary
antibodies
 Signs of pneumonia /skin lesion Viral RNA + p24 antigen with
CD4 count monitors
treatment.
Nucleic acid amplification testing
(NAT)monitors viral load

88. HEPATITIS
 95% of hepatitis cases are due to 5 major
types:hepatitis A,B,C,D,E
 Serodiagnosis of previous exposure and recovery is
complex
 Testing methods include ELISA, PCR

89. HEPATITIS TESTS
VIRUS TRANSMISSION INCUBATION
PERIOD
TEST FOR ACUTE
INFECTION
Hepatitis A Fecal-oral Av 30 Days (Range 15-50
Days)
Igm Antibody To
Hepatitis A Capsid
Protein
Hepatitis B Sexual,Blood and
other body parts
Av 120 days
(range 45-160 days)
HBsAg;the best test is
IgM antibody to HBcAg
Hepatitis C Blood Commonly 6-9 wk(range
2wk-6mo)
ELISA initial test
PCR confirmatory
Hepatitis D Sexual,Blood and
other body fluids
2-8 wk Total antibody to delta
hepatitis shows if ever
infected
Hepatitis E Fecal-oral Av 26-42 d(range,15-64d)

90. CANDIDA
 Candidiasis- usually caused by C. albicans
 Identifying candida Ab can be helpful for diagnosing systemic
candidiasis
 Tests used- Immunodiffusion,latex agglutination for candida
antigen
 Refrence Values
 Normal –ve for candida Abs
 Clinical Implications
 A titer ≥ 1:8 indicates systemic infection
 A fourfold increase in titres of paired blood samples 10-14
days apart indicate acute infection
 Long term IV antibiaotic therapy and diabetic patients- risk

91. Blood groups
 Blood is grouped according to presence or absence of specific blood
group antibodies
 Specifical linked sugars determine the antigenic activities.
 Relationship b/w Blood Antigens and Antibodies
Antigen present on
RBC
Antibodies present in
Serum
Major Blood Gp
Designation
NONE ANTI A , ANTI B O (UNIVERSAL DONOR)
A ANTI B A
B ANTI A B
AB NONE AB(UNIVERSAL
RECEPIENT)

92. Rh Typing
 Human blood is classified as Rh +ve or -ve
 Relates to presence or absence of D antigen on the RBC
membrane.(now called the Rh1[D] antigen
 Rh –ve individuals may develop antibodies against Rh
positive antigens if they are challenged through a transfusion
of Rh +ve blood or through a fetomaternal bleed from an Rh
+ve fetus
 Rh typing must be done because:
 Rh +ve blood administered to Rh –ve person may sensitize
the person to form anti-D(Rh1)
 Rh +ve blood to person having serum anti-D. ~Fatal
 Rh –ve pregnant women:RhIG dose antepartum at 28 weeks
of gestation and a postpartum inj. Shortly after delivery of an
Rh +ve infant

93. Coomb’s Antiglobulin Test
 Direct Coombs test -detects Ag-Ab complexes on the RBC
membrane
 Used to test for autoimmune hemolytic anemia
 Indirect Coombs test -detects anti-RBC antibodies in the
serum
 Used in prenatal testing of pregnant women, and in
testing blood prior to transfusion.
 Clinical Implications
 Helps in diagnosing-
• Hemolytic disease of the newborn
• Acquired hemolytic anemia
• Transfusion reaction

94. Conclusion
 Laboratory and diagnostic tests are tools which when
used in conjunction with a thorough history and physical
examination may confirm a diagnosis or provide
information about patients status and response to
therapy.
 Test selections are based on subjective clinical
judgement, national recommendations and evidence
based health care
 Effective communication is the key to achieving desired
outcomes,preventing misunderstanding and errors,and
helping patients feel they are informed partners and are
connected to the diagnostic process.