The document discusses advanced diagnostic technologies used in public health. It describes various diagnostic tests including immunopathology, molecular biology, clinical chemistry, hematology and others. It provides details on specific technologies like ELISA, PCR, gel electrophoresis and their applications in detecting diseases and conditions like HIV, hepatitis C, tuberculosis and others. The document also outlines IPHS standards for availability of different laboratory services at hospitals of varying sizes.

1. Advanced Diagnostic
Technologies in Public
Health
Dr Abhay Dhanorkar
2/7/2013 1

2. Scope
• Introduction
• IPHS standards for availability of laboratory services at various
hospitals.
• Classification of diagnostics tests
• Immunopathology
• Molecular Biology
• Clinical Chemistry
• Haematology
• Cytopathology
• Histopathology
• Radiology
• Electrophysiology
• Endoscopy
• Summary
2/7/2013 2

3. Introduction
• A diagnostic test is any kind of medical test
performed to aid in the diagnosis or detection of
disease.
• It may be used to diagnose diseases or measure
the progress or recovery from disease or confirm
that a person is free from disease.
• Some medical tests are parts of a simple physical
examination which require only simple tools in
the hands of a skilled practitioner and can be
performed in an office environment.
2/7/2013 3

4. Introduction contd……
• Some other tests require elaborate equipment
used by medical technologists or the use of a
sterile operating theatre environment.
• Some tests require samples of tissue or body
fluids to be sent off to a pathology lab for
further analysis.
• Some simple chemical tests such as urine pH,
can be measured directly in the physicians
office.
2/7/2013 4

5. Introduction contd……
• However, with advancements in health care, a
large array of diagnostic tests have become
available. Various modern (and often,
expensive) diagnostic modalities are often
routinely used in medical world.
• According to IPHS standards stated as a part of
NRHM, the some laboratory facilities should
be available at various levels.
2/7/2013 5

6. IPHS standards for availability of laboratory
services at 31 to 50 bedded hospitals
2/7/2013 6

7. For 51-100 Bedded (All as in 31-50 bedded
with the following additional facilities)
2/7/2013 7

8. For 101-200 Bedded (All as in 51-100 bedded
with the following additional facilities)
Speciality Diagnostic Services / Tests
Colonoscopy, Bronchoscopy, Arthroscopy, Laparoscopy
Endoscopy
(Diagnostic), Colposcopy, Hysteroscopy
Serology RA factor test CPK, Lepto spirosis (Rapid test / ELISA)
HSG, Ultrasonography Colour Doppler, Spiral CT scan,
Radiology
MRI 0.5 TESSLA
Biochemistry Glycosylated Hemoglobin, Blood gas analysis
2/7/2013 8

9. For 201-300 Bedded (All as in 101-200 bedded
with the following additional facilities)
2/7/2013 9

10. For >300 Bedded (All as in 201-300 bedded
with the following additional facilities)
Speciality Diagnostic Services
Angiography, Multislice CT, Multislice
Radiology
MRI
Bone Marrow Biopsy,Pleural Biopsy,
Biopsy
Pericardial tapping
Gastroscopy (Oesophagus, stomach,
Endoscopic Specialised Procedures deudenum), Sigmoid, Laproscopy and
and Diagnostic Colonoscopy, Bronchoscopy and
Foreign Body Removal
2/7/2013 10

11. Classification
• The various modern diagnostic technologies can
be classified as
– Immunopathology
– Molecular Biology
– Clinical Chemistry
– Haematology
– Cytopathology
– Histopathology
– Radiology
– Electrophysiology
– Endoscopy
2/7/2013 11

12. Diagnostic Technologies in
Immunopathology
• Antibodies are produced in response to
antigenic stimulation.
• Immunoassays (antigen antibody reactions)
can be used for detection of either antigens or
antibodies. For detecting antigens, the
corresponding specific antibody should be
used as one of the reagents and vice versa.
2/7/2013 12

13. Immunopathology contd…
The technologies available are –
• Precipitation immunoassays : It is based on the occurrence of
precipitation when large complexes of antigens and antibodies
combine to form an insoluble lattice.
Ex. :- Widal test and the Weil-Felix test.
• Particle immunoassay : Here specific antigens are coated onto a
particle and on reaction with antibody under test, the
agglutination is made more visible. Reverse agglutination where
the antibody is coated onto the particle is also performed. The
particle used may be RBC, latex or gelatin.
Ex. :- 1) TPHA (Treponema pallidum Hemagglutination).
2) Reverse passive hemagglutination (RPHA) for hepatitis B surface antigen (HBsAg).
3) Latex agglutination is used in measurement of hCG for qualitative pregnancy tests
2/7/2013 13

14. Immunopathology contd…
Radioimmunoassay :
• Radioimmunoassay (RIA) is used to test antigens
(e.g.hormone levels in the blood).
• It is extremely sensitive and extremely specific, but requires a
sophisticated apparatus and is costly. It also requires special
precautions, since radioactive substances are used.
• Therefore, today it has been largely supplanted by the ELISA
method, where the antigen-antibody reaction is measured
using colorometric signals instead of a radioactive signal.
• To perform a radioimmunoassay, a known quantity of an
antigen is made radioactive, frequently by labeling it with
gamma-radioactive isotopes of iodine attached to thyrosine.
2/7/2013 14

15. Immunopathology contd…
• This radiolabeled antigen is then mixed with a known
amount of antibody for that antigen and as a result,
the two chemically bind to one another.
• Then, a sample of serum from a patient containing an
unknown quantity of that same antigen is added. This
causes the unlabeled (or “cold”) antigen from the
serum to compete with the radiolabeled antigen for
antibody binding sites.
Applications in public health :
Ex. Thyroid hormone levels in goiter endemic areas.
2/7/2013 15

16. Immunopathology contd…
Enzyme Linked Immunosorbent Assay (ELISA) :
• This is a technique used mainly in immunology to
detect the presence of an antibody or an antigen
in a sample.
• In ELISA an unknown amount of antigen is affixed
to a surface and then a specific antibody is
washed over the surface so that it can bind to the
antigen.
• This antibody is linked to an enzyme and in the
final step a substance is added that the enzyme
can convert to some detectable signal.
2/7/2013 16

17. Immunopathology contd…
Applications in public health :
– HIV test or West Nile Virus.
ELISA can be used for detecting tumour
markers for certain cancers, e.g. Prostate
Specific Antigen (PSA) in carcinoma
prostate.
2/7/2013 17

18. Immunopathology contd…
Fluorescent immunoassay :
• When fluorescent molecules are irradiated with light at
appropriate wavelengths, an electron in the ground state is
transited into the excited state. As the electron returns to
the ground state, physical energy is released in the form of
a photon which is detectable.
Applications in public health :
• For detecting antigens in tissue sections in kidney biopsies.
• Use of Auramine rhodamine stain in detection of tubercle
bacilli in smears shown to have better sensitivity than the
conventional ZN stain.
• To detect the concentration of drugs, hormones and
proteins and polypeptides.
2/7/2013 18

19. Diagnostic Technologies in
Molecular Biology
Diagnostic Technologies in Molecular Biology
• Molecular biology is the study of biology at a molecular
level.
• Molecular biology chiefly concerns itself with
understanding the interactions between the various
systems of a cell, including the interactions between
DNA, RNA and protein biosynthesis and learning how
these interactions are regulated.
• The tools of molecular biology is extremely useful in
diagnosis, therapy, epidemiologic investigations and
infection control.
2/7/2013 19

20. Molecular Biology contd…
• Ease of performance, reproducibility, sensitivity
and specificity of molecular tests are important,
cost and potential contribution to patient care
are also of concern.
• Molecular methods may be an improvement over
conventional microbiologic testing as they are
most practical and useful application is in
detecting and identifying infectious agents for
which routine growth-based culture and
microscopy methods may not be adequate.
2/7/2013 20

21. Molecular Biology contd…
Gel electrophoresis :
• It is one of the principal tools of molecular biology. The
basic principle is that DNA, RNA and proteins can all be
separated by means of an electric field.
• In agarose gel electrophoresis, DNA and RNA can be
separated on the basis of size by running the DNA
through an agarose gel.
• Proteins can be separated on the basis of size by using
an SDS-PAGE gel, or on the basis of size and their
electric charge by using 2D gel electrophoresis.
2/7/2013 21

22. Molecular Biology contd…
Hybridisation assays :
• When the hybridization reaction is used to analyse the
nucleic acid content of an unknown sample, the
process is known as a hybridization assay.
• The property of complimentary base pairing allows
fragments of known composition (the probes) to
interrogate an unknown for the presence of matching
(complimentary) sequences.
• The detection of the hybrids can be done a variety of
technologies including radioisotope labels,
fluorochrome based detection and enzyme based
systems.
2/7/2013 22

23. Molecular Biology contd…
• Liquid phase hybridization : When both sample
and probe are in solution.
• Solid support hybridization : In these assays,
hybridization occurs in a biphasic environment, a
solid phase (usually sample) and a liquid phase
(usually probe).
• Southern and Northern hybridization assays :
These combine electrophoretic separation of test
nucleic acids with transfer to a solid support and
subsequent hybridization.
2/7/2013 23

24. Molecular Biology contd…
• The original procedure was described by EM
Southern and the test nucleic acid was DNA.
When RNA is the nucleic acid under test, the
technique is called northern blotting by
analogy.
• In situ hybridization : This is the detection of
specific genetic information within a
morphological context (intact tissue, cells).
2/7/2013 24

25. Molecular Biology contd…
Amplification technology :
• Amplification systems are enzyme based processes in
which a single enzyme or multiple enzymes synthesize
copies of target nucleic acid.
• All result in production of billions of copies of the
amplified product in a few hours.
• These techniques are subject to contamination from
product molecules of previous amplifications and
hence false positivity is high.
• However, special lab design, practices and workflow
have helped to reduce false positives to an acceptable
range.
2/7/2013 25

26. Molecular Biology contd…
Polymerase Chain Reaction (PCR)
• It is a simple in vitro chemical reaction that permits
synthesis of large quantities of nucleic acid.
• This is brought about by heating the reaction mixture
to separate the strands of the DNA, then cooled to
permit the primers to anneal to the target DNA in a
sequence specific manner. The DNA polymerase then
initiates extension from end.
• Thus the whole process is carried out in a
programmable thermocycler which controls the
temperatures at which various steps occur.
2/7/2013 26

27. Molecular Biology contd…
• Reverse transcriptase PCR (RT-PCR) : PCR was initially
described to amplify DNA. RT-PCR was developed to
amplify RNA targets
• Nested PCR : This variation increases the sensitivity
and specificity of PCR. The products of the first round
of amplification are subject to second round of
amplification with a second set of primers.
• Real time PCR : Here the target amplification and
detection occur simultaneously.
• The computer software supporting the thermocycler
monitors the data throughout the PCR at every cycle
and generates a plot.
2/7/2013 27

28. Molecular Biology contd…
Applications of molecular biology in Public
Health
• Pathogen detection by hybridisation : The
DNA of the infectious agent is detected
directly in the clinical specimens by DNA
probes.
2/7/2013 28

29. Molecular Biology contd…
• DNA probes for culture identification : Probes are available
for various organisms like Mycobacterium tuberculosis,
Chlamydia trachomatis, Neisseria gonorrhoeae, Human
papilloma virus, Hepatitis C virus, Cytomegalovirus and
Herpes simplex virus.
• This is especially important for slow growing organisms like
Mycobacteria, fungi etc. Identification of cultured
Mycobacteria by conventional methods is slow and time
consuming.
• The use of probes for this purpose permits identification
from cultures within one working day and sensitivity
(95.4%) and specificity (99%) are excellent.
2/7/2013 29

30. Molecular Biology contd…
• DNA amplification for diagnosis :
• Hepatitis C Virus- Detection of the virus by
reverse transcriptase PCR confirms current
infection and has a role in diagnosis and
monitoring response to therapy. Development of
Quantitative PCR allows quantification of HCV
which is important in prognosis and monitoring
of therapy.
• HIV : Newborns upto 18 months. Quantitation of
HIV virus is widely used for prognosis and for
evaluation of response to antiretroviral therapy
2/7/2013 30

31. Molecular Biology contd…
Mycobacterium tuberculosis :
• In general the sensitivity of these assays for specimens
for which the smear for acid fast bacilli (AFB) is positive
is excellent (95-100%). It is lower for specimens that
are AFB smear negative (50-80%).
• Currently, the amplification processes cannot replace
the AFB smear because the latter is used to determine
the level of infectivity of patients and in gauging the
initial response to therapy.
• At present the role of amplification assays remains
complimentary to microscopy and culture.
2/7/2013 31

32. Molecular Biology contd…
• Sexually Transmitted Diseases : Amplification assays
have been developed for Neisseria gonorrhoeae and
Chlamydia trachomatis.
• Fungi : PCR assays for diagnosis of invasive
Candidiasis and Aspergillosis have been developed.
• Detection of antimicrobial resistance : Molecular
detection of the Mec-A gene is now considered a
reference method for assessing Methicillin resistance
in Staphylococci.
• Used in detection of resistance to rifampicin and
isoniazid.
2/7/2013 32

33. Molecular Biology contd…
Molecular Epidemiology :
• The techniques of molecular typing are useful
not only in research settings but also in real
life clinical and public health problems.
– e.g. prediction of response to interferon therapy is
important in patients with Hepatitis C virus
infection.
• HCV genotypes 1b and 1a appear less likely to
respond to interferons.
2/7/2013 33

34. Diagnostic Technologies in
Clinical Chemistry
• Colorimetry : This is performed in a device that
measures the absorbance of particular wavelengths
of light by a specific solution.
• Changeable optic filters are used in the colorimeter
to select the wavelength of light which the solute
absorbs the most, in order to maximize accuracy.
• The usual wavelength range is from 400 to 700
nanometres (nm). In modern colorimeters the
filament lamp and filters may be replaced by several
light-emitting diodes of different colors.
2/7/2013 34

35. Clinical Chemistry contd…
• Applications in public health : Routine
analytes like urea, creatinine, glucose, uric
acid and also hemoglobin in hematology.
• Levels in blood of routine analytes forms the
basis of the diagnosis of diabetes,
hyperlipidemia, metabolic syndrome etc.
2/7/2013 35

36. Clinical Chemistry contd…
Nephelometry :
• This is a method for measuring the concentration of a
solution that contains particles that are too large for
colorimetry/ absorption spectroscopy.
• When a collimated light beam strikes a particle in
suspension, portions of the light are absorbed,
reflected, scattered and transmitted.
• Nephelometry is the measurement of the light
scattered by a particulate solution.
• Applications in public health : Measurement of
antigen antibody complexes formed in immunoassays.
Detection of IgG, IgM, IgA.
2/7/2013 36

37. Clinical Chemistry contd…
Electrophoresis : Electrophoresis is the separation
of charged compounds based on there electrical
charge.
• Common support media include cellulose
acetate, agarose and polyacrylamide gel.
• Once separation has occurred, the support
medium is treated with dyes to stain and identify
the separated fractions.
• To obtain a quantitative profile of the separated
fractions, densitometry is performed on the
stained support medium.
2/7/2013 37

38. Clinical Chemistry contd…
Applications in public health :
• Separation of serum proteins :
– Patterns of hypoproteinemia in malnutrition or gross
loss of protein show decreases in all fractions with
dramatic reduction in albumin.
– Cirrhosis of the liver shows a specific pattern with
severe reduction of albumin and increased
immunoglobulins.
– The pattern in monoclonal gammopathies (multiple
myeloma) is very characteristic.
– Separation of hemoglobins : This is important in the
diagnosis of various abnormal hemoglobins like
thalassemia, sickle cell anemia etc.
2/7/2013 38

39. Clinical Chemistry contd…
Chromatography : Chromatography is a separation method based on
the different interaction methods of the specimen compounds with
the mobile phase and with the stationary phase, as the compounds
travel through a support medium. The compounds interacting more
strongly with the stationary phase are retained longer in the
medium than those that favor the mobile phase.
• Gas chromatography : It is used for naturally volatile or those
which can be easily converted to a volatile form.
• Liquid chromatography : It is used for too unstable or insufficiently
volatile for gas chromatography.
• High Performance Liquid Chromatography : It is used for analyzing
air and water pollutants, monitoring pesticide levels in the
environment. Used In Sickle cell Disease diagnosis in infants.
Detection of additives / chemicals in food.
2/7/2013 39

40. Clinical Chemistry contd…
• Applications in public health : Used for
determination of drugs and chemicals in body
fluids (toxicology).
• Detection of additives / chemicals in food by
High performance liquid chromatography.
• Environmental and water pollutants can be
detected with accuracy through the use of
various chromatographic procedures.
2/7/2013 40

41. Clinical Chemistry contd…
Automation in clinical chemistry :
• Process a large volume of tests quickly. This is
possible through the increased speed of testing.
• Most automated chemistry analyzers,
photometric methods of analysis such as
colorimetry, spectrophotometry or nephelometry
etc.
• Calculations, calibration curves and quality
control are performed by the computers, thus
reducing errors and providing more accurate
results.
2/7/2013 41

42. Clinical Chemistry contd…
• The testing pathway in an analyser may be
a) Sequential testing- Multiple tests analysed
one after another on a single specimen.
b) Batch testing- All samples are loaded at the
same time and a single test is conducted on
each sample.
c) Parallel testing- More than one test is
analysed concurrently on a given clinical
specimen.
d) Random access testing- Any test can be
performed on any sample in any sequence.
2/7/2013 42

43. Diagnostic Technologies in
Hematology
Automated Instruments :
• These instruments have many different components to
analyze different elements in the blood.
• The cell counting components count the numbers and
types of different cells within the blood. The results are
printed out or sent to a computer for review.
• It aspirate a very small amount of the specimen
through narrow tubing. Within this tubing, there are
sensors that count the number of cells going through it
and can identify the type of cell; this is flow cytometry.
• The two main sensors used are light detectors and
electrical impedance.
2/7/2013 43

44. Hematology contd…
• One way the instrument can tell what type of
blood cell is present is by size.
• Other instruments measure different
characteristics of the cells to categorize them.
• Because an automated cell counter samples and
counts so many cells, the results are very precise.
• In addition to counting, measuring and analyzing
red blood cells, white blood cells and platelets,
automated hematology analyzers also measure
the amount of hemoglobin in the blood and
within each red blood cell.
2/7/2013 44

45. Diagnostic Technologies in
Cytopathology
Exfoliative cytology : The microscopic examination of
cells that have been shed from a lesion or have been
recovered from a tissue for the diagnosis of disease.
Applications in public health
• Cervical cytology : Exfoliative cytology from the
uterine cervix is valuable in picking up premalignant
lesions of the cervix.
• It has an overall sensitivity of 80% and a specificity of
99.4% for cytologic screening for cervical cancer.
• The sensitivity was slightly lower for mild and
moderate dysplasia (78.1%) and slightly higher for
carcinoma in situ and severe dysplasia (81.4%) and
invasive carcinoma (82.3%)
2/7/2013 45

46. Cytopathology contd…
Fine Needle Aspiration Cytology :
• Fine Needle Aspiration biopsy is safer and less traumatic
than an open surgical biopsy and significant complications
are usually rare, depending on the body site.
• Common complications include bruising and soreness.
There is also a risk that the cells taken do not enable a
definitive diagnosis.
• The technique is suitable to evaluation of lesions/ nodules
arising from breast, lymph nodes, thyroid, liver, kidney and
soft tissue.
• The sensitivity and specificity varies according to the organ
involved and also depends on the aspiration of a
representativeness of the sample.
2/7/2013 46

47. Cytopathology contd…
Diagnostic Technologies in Histopathology
• The tissue is removed from the body and then placed
in a fixative which stabilizes the tissues to prevent
autolysis.
• The samples are transferred to a cassette, a container
designed to allow reagents to freely act on the tissue
inside. This process is known as tissue processing.
• The processed tissue is then taken out of the cassette
and set in a mold. Through this process of embedding,
additional paraffin is added to create a paraffin block.
2/7/2013 47

48. Cytopathology contd…
• The process of embedding then allows the
sectioning of tissues into very thin (2 – 7
micrometer) sections using a microtome.
• The microtome slices the tissue ready for
microscopic examination. The slices are thinner
than the average cell and are layered on a glass
slide for staining.
• To see the tissue under a microscope, the
sections are stained with one or more pigments.
• The most commonly used stain in histopathology
is a combination of hematoxylin and eosin.
2/7/2013 48

49. Cytopathology contd…
• Applications in public health : Malignancies
and also some non neoplastic conditions like
tuberculosis and other infections.
2/7/2013 49

50. Cytopathology contd…
• Immunohistochemistry : Immunohistochemistry or
IHC refers to the process of localizing proteins in cells
of a tissue section exploiting the principle of antibodies
binding specifically to antigens in biological tissues.
• Immunohistochemical staining is widely used in the
diagnosis of abnormal cells such as those found in
cancerous tumors.
• Applications in public health : Recognition of specific
molecular markers like S100, Cytokeratin etc. helps in
identifying the origin and hence the diagnosis of
various tumours and conditions.
2/7/2013 50

51. Radiological Techniques
X-ray : For detection of pathology of the skeletal system
and some disease processes in soft tissue, e.g.
pneumonia, lung cancer or pulmonary edema and the
abdominal X-ray, which can detect ileus (blockage of
the intestine), free air (from visceral perforations) and
free fluid (in ascites).
Applications in public health : Chest x ray was the
backbone of National Tuberculosis Control Programme
in 1962.
• However it is included in the diagnostic algorithm of
RNTCP where no sputum sample is positive/ two
negative smears in a symptomatic patient.
• In occupational health the ILO criterion for diagnosis of
pneumoconiosis uses findings of x ray chest only.
2/7/2013 51

52. Radiology contd…
• DEXASCAN : DEXA Scan stands for Dual Energy X-
Ray Absorptiometry. Two different types of X- ray
scan the body and the images are subtracted by
the computer giving a very accurate estimation of
bone density/body fat.
• It is used to detect the presence of osteoporosis
in men and women with particular risk factors,
screen for osteoporosis, particularly in women
making decisions about hormone replacement
therapy at menopause.
2/7/2013 52

53. Radiology contd…
• Angiography : It is the study of blood vessels
with a contrast medium.
• It has a great role in study of coronaries to
detect the status of these vessels and decide
the treatment modality for the patient.
• With the epidemic of coronary artery disease
angiography will go a long way in the final
management of the patients.
2/7/2013 53

54. Radiology contd…
Mammography :
• Mammography is the process of using low-dose
X-rays, high contrast, high-resolution film and an
X-ray system designed specifically for imaging the
breasts.
• The goal of mammography is the early detection
of breast cancer, typically through detection of
characteristic masses and/or micro calcifications.
• Mammography has been shown to reduce
mortality from breast cancer.
2/7/2013 54

55. Radiology contd…
• USG:-
– Obstetric use
– Cardiac scan
– Renal, liver and gallbladder scans.
– Musculo-skeletal imaging of muscles, ligaments
and tendons,
– Eye scans
– Testicle, thyroid, salivary glands and lymph nodes
scan.
– To guide interventional procedures (FNAC)
2/7/2013 55

56. Radiology contd…
• Applications in Public Health : This technique in
antenatal cases is practiced to
– Date the pregnancy
– Confirm fetal viability,
– Determine location of fetus,
– Intrauterine vs ectopic,
– Location of the placenta.
– Number of fetuses
– Major physical abnormalities,
– Assess fetal growth
– Fetal movement and heartbeat.
• Ultrasound is also increasingly being used in trauma
and first aid cases, with emergency ultrasound
becoming a stable of most emergency response teams.
2/7/2013 56

57. Radiology contd…
CT scan :
• CT scan works on the principle that cross
sectional slices of the body are produced using X
rays, followed by processing by the computers to
study detailed anatomy of the specific location or
slice.
• The modification of conventional CT is spiral
where the X-ray tube/ detector combination
rotates continuously around the patient creating
a spiral and helps in generating high quality
images.
2/7/2013 57

58. Radiology contd…
• Magnetic Resonance Imaging : Charged spinning
particles such a protons behave like tiny bar magnets
and are used to produce image of biological tissue.
• It does not use ionizing radiation hence is safe with no
known biological hazards.
• It provides excellent tissue contrast with good
resolution.
• Images can be obtained in any plane (Multiplanar
Imaging) and does not produce artifacts due to bone
and is an ideal imaging modality for spine, posterior
fossa and musculoskeletal system.
2/7/2013 58

59. Radiology contd…
Radionuclide scan :
• A radionuclide scan is a way of imaging bones, organs and
other parts of the body by using a small dose of a
radioactive chemical.
• Cells which are most ‘active’ in the target tissue or organ
will take up more of the radionuclide. So, active parts of the
tissue will emit more gamma rays than less active or
inactive parts.
• The gamma rays which are emitted from inside the body
are detected by the gamma camera, are converted into an
electrical signal and sent to a computer.
• The computer builds a picture by converting the differing
intensities of radioactivity emitted into different colours or
shades of grey.
2/7/2013 59

60. Radiology contd…
• Public Health Importance
– Bone scan : Used to detect areas of bone where
there is cancer, infection or damage.
– Kidney scan : Used to detect scars on the kidney
and how well urine drains from the kidney to the
bladder.
– Lung Perfusion Scan : Detects pulmonary
embolus.
2/7/2013 60

61. CT scan, its modifications and their uses in
public health
2/7/2013 61

62. MRI : Clinical uses
2/7/2013 62

63. IPHS Standards : Suggested
Availability of radiological studies
2/7/2013 63

64. Electrophysical Technologies
• Various functional disturbances sometimes detectable
only via analysis of electric potentials produced by
some organs (tissues) as a manifestation of their
function (ECG, EEG, EMG, ERG and others).
• Evaluation of these signals is performed either in the
“time domain” (detection of particular specific peaks
and wave complexes - “grapho-elements” - and
description of their time and amplitude characteristics)
or in the “frequency domain” (frequency spectrum
characteristics).
• At present this is done almost exclusively with the use
of computers.
2/7/2013 64

65. Electrophysiology contd…
Electroencephalography :
• This is the neurophysiologic measurement of the electrical
activity of the brain by recording from electrodes placed on
the scalp or in special cases, subdurally or in the cerebral
cortex. It represent an electrical signal (postsynaptic
potentials) from a large number of neurons.
• Each electrode is connected to an input of a differential
amplifier, which amplifies the voltage between them. The
resulting voltage signal is filtered which is shown on paper
or displayed on a computer screen. Uses in
– Epilepsy and syncope
– Sleep disorders
– Coma and brain death
2/7/2013 65

66. Electrophysiology contd…
Electrocardiography : An electrocardiogram records the
electrical activity of the heart over time.
• Electrodes on different sides of the heart measure the
activity of different parts of the heart muscle.
• An ECG displays the overall rhythm of the heart and
weaknesses in different parts of the heart muscle.
• Applications in public health : It is the best way to measure
and diagnose abnormal rhythms of the heart in
– Damage to the conductive tissue carrying electrical
signals,
– High or low potassium.
– Myocardial infarction (MI)
2/7/2013 66

67. Electrophysiology contd…
Electromyography :
• Electromyography (EMG) is a technique for
evaluating and recording the activation signal of
muscles.
• An electromyograph detects the electrical
potential generated by muscle cells when these
cells contract and also when the cells are at rest.
• EMG is used to diagnose two general categories
of disease : neuropathies and myopathies.
2/7/2013 67

68. ENDOSCopy
• Different types of endoscopies are performed for diagnostic
purposes of carcinoma and other pathologies. These may
be rigid or fibreoptic.
• Direct:-
– Laryngoscopy
– Broncoscopy
– Colonoscopy
– Gastroscopy
– Nasopharyngoscopy
– Sigmoidoscopy
– Hysteroscopy
• Indirect:-
– Laryngoscopy
2/7/2013 68

69. References
• Rajvir Balwar, Text book Public Health and Community Medicine,
1st Edition, AFMC Pune in collabration with WHO, Dept Of
Commnity Medicine, 2008.
• Indian Public Health Standards (IPHS) Guidelines for Sub-
District/Sub-Divisional Hospitals (31 to 100 Bedded) Revised 2012 ,
DGHS, MOHFW, Govt Of India, June 2012.
• Indian Public Health Standards (IPHS) Guidelines for District
Hospitals (101 to 500 Bedded) Revised 2012, DGHS, MOHFW, Govt
Of India, June 2012.
• http://www.biomerieux.com/en/advanced-technologies
• World Health Organization, Laboratory Support to Emerging
Diseases. World Health Organization Regional Office for South-East
Asia New Delhi, 2008.
• www.whoindia.org/LinkFiles/Public_Health_Laboratory_Networkin
g_SEARO_recommendations _on_networking_of_PHL
2/7/2013 69

70. • The Diagnostics Innovation Map: Medical Diagnostics for the Unmet
Needs of the Developing World, WHO BIO Ventures for Global
Health,2010.
• Estimating the Global Health Impact of Improved Diagnostic Tools
for the Developing World. Santa Monica, Rand Institute,2007.
• Sen J, Belli A "S100B in neuropathologic states: the CRP of the
brain?". J. Neurosci. Res.2007; 85 (7): 1373–80.
• http://mohfw.nic.in/NRHM/iphs.htm
• http://testequipment.globalspec.com/LearnMore/Labware_Scientif
ic_Instruments/Analytical_Instruments/Chromatographs/HPLC
• http://www.google.co.in/imgres?um/diagnostic%technologies/php.
2/7/2013 70

71. 2/7/2013 71