Diagnosis of Infectious DiseasesDiagnosis of Infectious Diseases

Dr. G. V. MaliDr. G. V. Mali Bharati Vidyapeeth’sMBSK Kanya Bharati Vidyapeeth’sMBSK Kanya Mahavidyalaya, Kadegaon. Dist. Sangli 415304.Mahavidyalaya, Kadegaon. Dist. Sangli 415304.

Maharashtra ( India)Maharashtra ( India)

Laboratory diagnosis of infectious diseasesLaboratory diagnosis of infectious diseases

1- Microscopic examination of the clinical specimen1- Microscopic examination of the clinical specimen

2- Isolation of the culture & its identification based on2- Isolation of the culture & its identification based on biochemical reactionsbiochemical reactions 3- Serological identification / Immunological 3- Serological identification / Immunological identification of Ags or Abs. identification of Ags or Abs. 4- Nucleic acid based / Molecular biology techniques 4- Nucleic acid based / Molecular biology techniques

( Among these 1 & 2 are conventional methods )( Among these 1 & 2 are conventional methods )

Limitations of the conventional methods – Limitations of the conventional methods –

1. Lengthy, time consuming and tedious.1. Lengthy, time consuming and tedious.

2. Culturing of certain organisms like viruses, fungi &2. Culturing of certain organisms like viruses, fungi & parasites may not be possibleparasites may not be possible

3. Associated with risk.3. Associated with risk.

4. Impossible in all laboratories, requires 4. Impossible in all laboratories, requires sophisticated labs. e. g Mycobacteriasophisticated labs. e. g Mycobacteria

5. Culture may be negative due to prior antimicrobial 5. Culture may be negative due to prior antimicrobial therapy.therapy.

Serological identification of Ags / Abs Serological identification of Ags / Abs OR OR

Immunological assays Immunological assays

Important Advantages -Important Advantages -

They provide early diagnosisThey provide early diagnosis

Important for uncultivable organisms in the lab.Important for uncultivable organisms in the lab.

Useful for differential diagnosis of certain Useful for differential diagnosis of certain

diseases e.g. Typhoid feverdiseases e.g. Typhoid fever

Useful to measure the antibody level (titer).Useful to measure the antibody level (titer).

Conventional Serological MethodsConventional Serological Methods

1.1. PrecipitationPrecipitation

2.2. Agglutination Agglutination

3.3. Haemagglutination Haemagglutination

4.4. Haemagglutination inhibition Haemagglutination inhibition

5.5. Complement Fixation Test Complement Fixation Test

6.6. Fluorescent Antibody Test Fluorescent Antibody Test

1. 1. Precipitation:Precipitation: Reaction between soluble antigen and antibody = Reaction between soluble antigen and antibody = Insoluble PPTInsoluble PPT

- If ppt sediments – Precipitation- If ppt sediments – Precipitation - If remains suspended as floccules – flocculation- If remains suspended as floccules – flocculation

Carried out either in liquid media / in gels Carried out either in liquid media / in gels e.g. agar, agarose, polyacrylamidee.g. agar, agarose, polyacrylamide

Can be Qualitative or quantitativeCan be Qualitative or quantitative

Sensitive, can detect as little as 1Sensitive, can detect as little as 1μμg of proteing of protein - Applications- Applications Slide test ( Qualitative ) – VDRL test for syphilisSlide test ( Qualitative ) – VDRL test for syphilis Tube test ( Quantitative )– Kahn test for syphilis Tube test ( Quantitative )– Kahn test for syphilis

-- Precipitation in gel is called immunodiffusionPrecipitation in gel is called immunodiffusion . Used for detection of fungal antigens. Used for detection of fungal antigens

-- Immunoelectrophoresis – Immunoelectrophoresis – -- Combination of ectrophoresis & ImmunodiffusionCombination of ectrophoresis & Immunodiffusion - Here, process of immunodiffusion is enhanced - Here, process of immunodiffusion is enhanced electrically.electrically.

- Two Common ways of Immunoelectrophoresis – - Two Common ways of Immunoelectrophoresis – Counter immunoelectrophoresis –Counter immunoelectrophoresis – For detection of HBs surface Ags, specific For detection of HBs surface Ags, specific

bacterial & Cryptococcal Ags.bacterial & Cryptococcal Ags. Rocket immunoelectrophoresis –Rocket immunoelectrophoresis – Quantitative estimation of Ags Quantitative estimation of Ags

2. Agglutination2. Agglutination Reaction of antibodies with Reaction of antibodies with

particulate or insoluble antigens in particulate or insoluble antigens in presence of an electrolyte atpresence of an electrolyte at

suitable pH & temp. suitable pH & temp. = formation of visible clumps= formation of visible clumps Applications- Applications- Slide test- primary diagnosis of Slide test- primary diagnosis of

typhoidtyphoid Tube test- Widal test used for Tube test- Widal test used for

diagnosis of typhoid feverdiagnosis of typhoid fever Tube test for BrucellosisTube test for Brucellosis Weil felix test for typhus feverWeil felix test for typhus fever Passive agglutination :Passive agglutination : Agglutination of soluble Ags by Agglutination of soluble Ags by

coating them on inert particles like coating them on inert particles like latex beads or carbon particleslatex beads or carbon particles

E.g. RPR test ( Rapid plasma E.g. RPR test ( Rapid plasma reagin test ) to detect cardiolipin reagin test ) to detect cardiolipin antibodies in sera of syphilis antibodies in sera of syphilis patients.patients.

Agglutination

Passive AgglutinationPassive Agglutination

3. Haemagglutination3. Haemagglutination Agglutination of RBCs Agglutination of RBCs Useful for diagnosis of viral Useful for diagnosis of viral

infections infections e.g. influenza, mumps & e.g. influenza, mumps &

measles.measles. Haemagglutination Haemagglutination

inhibition test : inhibition test : To detect Abs in serum To detect Abs in serum

against haemagglutinating against haemagglutinating viruses .viruses .

Positive Test : Positive Test : Virus + RBCs + test serum Virus + RBCs + test serum

= No hemagglutination = No hemagglutination

Negative Test : Negative Test : Virus + RBCs + test serum Virus + RBCs + test serum

= Hemagglutination = Hemagglutination

4. Complement Fixation Test4. Complement Fixation Test Complement – Complex system of Complement – Complex system of some serum proteins , activated by some serum proteins , activated by Ag-Ab complexesAg-Ab complexes• Ability to fix on Ag-Ab complex , Ability to fix on Ag-Ab complex , if Ab is involvedif Ab is involved• In presence of appropriate Ab, ‘C’ In presence of appropriate Ab, ‘C’ causes lysis of RBCs, bacteriacauses lysis of RBCs, bacteria• Two steps –Two steps –• 1.Complement Fixation Step1.Complement Fixation Step• Inactivated serum of patient + Ag + C Inactivated serum of patient + Ag + C = incubation at 37= incubation at 37oo C for 1 hr. C for 1 hr.

2. Indicator Step2. Indicator Step Addition of sheep RBCs & antisheep Addition of sheep RBCs & antisheep RBC antibodies )RBC antibodies ) No hemolysis = Positive test Hemolysis Hemolysis = Negative Test= Negative Test E.g. Wasserman test – for syphilis,E.g. Wasserman test – for syphilis, Also used for viral, fungal, Also used for viral, fungal, rickettsial, chlamydial & protozoal rickettsial, chlamydial & protozoal diseases.diseases.

5. Fluorescent Antibody Test 5. Fluorescent Antibody Test Use antibodies labeled with fluorescent dyes.Use antibodies labeled with fluorescent dyes. e.g. fluorescein isothiocynate (Green fluorescence ), e.g. fluorescein isothiocynate (Green fluorescence ),

Rhodamine B ( Orange red )Rhodamine B ( Orange red )

Two types – Two types – 1. Direct FAT 1. Direct FAT : Used to identify specific microorganisms : Used to identify specific microorganisms (antigens).(antigens).

Specimen ( Ag) is fixed on slide + labelled Abs = examined Specimen ( Ag) is fixed on slide + labelled Abs = examined under fluorescent microscope = under fluorescent microscope =

If fluorescene = + ve test. If fluorescene = + ve test. E.g. Diagnosis of Ags on E.g. Diagnosis of Ags on group A streptococci, group A streptococci,

enteropathogenic E.coli, H.influenzae type b, rabies etc.enteropathogenic E.coli, H.influenzae type b, rabies etc. 2. Indirect FAT : 2. Indirect FAT : Used to detect Abs in serum.Used to detect Abs in serum. Known Ag fixed on slide + test serum + labelled Known Ag fixed on slide + test serum + labelled antiimmunoglobulin = observation under fluro microscopeantiimmunoglobulin = observation under fluro microscope * If fluorescence = +ve test ( Abs are present )* If fluorescence = +ve test ( Abs are present ) * Used to detect Treponemal Abs for syphilis diagnosis.* Used to detect Treponemal Abs for syphilis diagnosis.

Direct and Indirect FATDirect and Indirect FAT

New immunological methods /ImmunoassaysNew immunological methods /Immunoassays 1. Enzyme linked immunosorbant assay ( ELISA )1. Enzyme linked immunosorbant assay ( ELISA ) 2 . Radioimmunoassay2 . Radioimmunoassay1.ELISA1.ELISA – – Uses antibodies linked to an enzyme, Uses antibodies linked to an enzyme, E.g. horseradish peroxidase or alkaline phosphatase.E.g. horseradish peroxidase or alkaline phosphatase. Antigen – antibody reactions are detected by enzyme Antigen – antibody reactions are detected by enzyme activity. activity.

The specific Antigen is added to the test well.The specific Antigen is added to the test well. An antibody linked to the enzyme is added to it.An antibody linked to the enzyme is added to it. It will bind if the antigen specific for it is present. It will bind if the antigen specific for it is present. To determine whether the enzyme-linked antibody is bound To determine whether the enzyme-linked antibody is bound in the well, substrate for the enzyme is added. in the well, substrate for the enzyme is added.

If the enzyme linked antibody is present, the substrate is If the enzyme linked antibody is present, the substrate is converted to a product that causes a color change.converted to a product that causes a color change.

Three ways of performing ELISA –Three ways of performing ELISA –

1.1. Indirect – Indirect – Wells coated with known Ags Wells coated with known Ags Test serumTest serum Add conjugate of anti-antibody linked Add conjugate of anti-antibody linked with enzyme ( HRPO) with enzyme ( HRPO) Detection of enzyme by addition of enzyme Detection of enzyme by addition of enzyme substrate ( ortho- phenylene –dihydrosubstrate ( ortho- phenylene –dihydro dichloride solution ) dichloride solution ) Development of yellow orange colour Development of yellow orange colour Positive testPositive test * Colour produced will be proportional* Colour produced will be proportional to the conc. of Abs.to the conc. of Abs. * Used for the detection of Abs * Used for the detection of Abs against HIV 1 & HIV 2, rubella against HIV 1 & HIV 2, rubella virus.virus.

SOLID PHASESOLID PHASESOLID PHASESOLID PHASE

ANTI-HUMAN IMMUNOGLOBULIN WITH DETECTOR

SAMPLE Ab

ANTIGEN

2. Competitive ELISA2. Competitive ELISA

Used for the detection of Abs in test sampleUsed for the detection of Abs in test sample

Competition between Abs & labelled known Abs.Competition between Abs & labelled known Abs.

If Abs are present in test serum, labelled Abs will not If Abs are present in test serum, labelled Abs will not bind & will not produce a colour bind & will not produce a colour = Positive test= Positive test

If Abs are absent in test serum, labelled Abs will bind If Abs are absent in test serum, labelled Abs will bind & produce colour & produce colour = Negative test= Negative test

3. Sandwich ELISA : 3. Sandwich ELISA :

Detection of Ags and not for AbsDetection of Ags and not for Abs Two types – Two types – Direct sandwich and Indirect SandwichDirect sandwich and Indirect Sandwich Direct Sandwich / Single Ab :Direct Sandwich / Single Ab : Abs are coated on solid surfaceAbs are coated on solid surface Test sample (Ag) Test sample (Ag) Enzyme linked known AbEnzyme linked known Ab

Indirect Sanwich / Double Ab : Indirect Sanwich / Double Ab : Abs are coated on solid surfaceAbs are coated on solid surface Test sample (Ag) Test sample (Ag) Second Ab ( known )Second Ab ( known ) Enzyme linked anti-antibody.Enzyme linked anti-antibody.

ELISA kits are available for both clinical ELISA kits are available for both clinical diagnostics and home use. These tests are used diagnostics and home use. These tests are used for everything from screening blood for anti-HIV for everything from screening blood for anti-HIV

antibodies to home pregnancy tests.antibodies to home pregnancy tests.

2. Radioimmunoassay ( RIA )2. Radioimmunoassay ( RIA )

Steps are very similar with ELISASteps are very similar with ELISA In RIA, instead of enzyme linked Abs , In RIA, instead of enzyme linked Abs ,

radiolabelled Abs i.e. antiglobulin radiolabelled Abs i.e. antiglobulin labelled with a radioactive compound is labelled with a radioactive compound is added. added.

The amount of radioactivity in wells The amount of radioactivity in wells provides an estimate of the titer of target provides an estimate of the titer of target antibody.antibody.

Immunoblotting : e.g. Western blot Immunoblotting : e.g. Western blot analysisanalysis

Technique of separation & detection of Ags.Technique of separation & detection of Ags. Ags (e.g. HIV Ags in serum) are first separated by Ags (e.g. HIV Ags in serum) are first separated by

polyacrylamide gel electrophoresispolyacrylamide gel electrophoresis Separation takes place on the basis of sizeSeparation takes place on the basis of size Separated molecules are transferred to another Separated molecules are transferred to another

matrix e.g. nitrocellulose membrane.matrix e.g. nitrocellulose membrane. Enzyme labelled Abs against the molecules of Enzyme labelled Abs against the molecules of

interest is added and then sbstrate is added for interest is added and then sbstrate is added for visualization.visualization.

Used to confirm the presence of specific Ags of HIV Used to confirm the presence of specific Ags of HIV 1 & HIV 2.1 & HIV 2.

Nucleic Acid Based Methods / Molecular Nucleic Acid Based Methods / Molecular Biology TechniquesBiology Techniques

It involves the study of relevant DNA sequence It involves the study of relevant DNA sequence by nucleic acid techniques. by nucleic acid techniques.

The most common methods are –The most common methods are –

A- Polymerase chain reaction (PCR):A- Polymerase chain reaction (PCR): B- Restriction fragment length polymorphismsB- Restriction fragment length polymorphisms ( RFLP)( RFLP)

C- Genetic probes (DNA or RNA probes):C- Genetic probes (DNA or RNA probes):

1.Polymerase Chain Reaction 1.Polymerase Chain Reaction Amplification of a short sequence of target DNA or Amplification of a short sequence of target DNA or

RNA which is then detected by a labeled probe.RNA which is then detected by a labeled probe.

Highly sensitive – detects infectious agents in host Highly sensitive – detects infectious agents in host tissues and vectors, even when a small number of tissues and vectors, even when a small number of host cells are infected. host cells are infected.

PCR can target and amplify a gene sequence that is PCR can target and amplify a gene sequence that is integrated into the DNA of infected host cells.integrated into the DNA of infected host cells.

It can also target and amplify un-integrated viral It can also target and amplify un-integrated viral gene sequences.gene sequences.

Very useful in the diagnosis of chronic-persistent Very useful in the diagnosis of chronic-persistent infections, such as retroviruses (bovine leukemia infections, such as retroviruses (bovine leukemia virus, caprine arthritis /encephalitis virus, etc.). virus, caprine arthritis /encephalitis virus, etc.).

Steps in PCR Steps in PCR Cells separated and lysed.Cells separated and lysed. Each cycle of PCR consists of three cycles:Each cycle of PCR consists of three cycles:

1.Denaturation of target DNA at 951.Denaturation of target DNA at 9500Cto separate 2 Cto separate 2 strands.strands.

2.Annealing step - in which the reaction mix is cooled to 2.Annealing step - in which the reaction mix is cooled to 55550 0 C to allow the primers to anneal to target sequenceC to allow the primers to anneal to target sequence

Primers are small segments of DNA , no more than Primers are small segments of DNA , no more than 20-30 nucleotides long.20-30 nucleotides long.

Primers are complementary to segments of opposite Primers are complementary to segments of opposite strands of the target sequence.strands of the target sequence.

3.Extension reaction in which primers initiate DNA 3.Extension reaction in which primers initiate DNA synthesis ( at 72synthesis ( at 7200C) using a DNA polymerase.C) using a DNA polymerase.

• These three steps constitute a thermal cycleThese three steps constitute a thermal cycle• Only the segments of target DNA between the primers Only the segments of target DNA between the primers

will be replicated.will be replicated. Each PCR cycle results in a doubling of target sequences.Each PCR cycle results in a doubling of target sequences. One cycle takes approximately 60-90 seconds.One cycle takes approximately 60-90 seconds.

Specific primers are designed for identification of Specific primers are designed for identification of different classes of pathogens. different classes of pathogens.

The best example is the use of sequences of the 16s The best example is the use of sequences of the 16s rRNA gene which is an evolutionarily conserved gene rRNA gene which is an evolutionarily conserved gene in bacterial species.in bacterial species.

Using such primers, one can determine the presence Using such primers, one can determine the presence of any bacteria from the sample. of any bacteria from the sample.

Positive PCR result needs to be further characterized Positive PCR result needs to be further characterized by hybridization with species-specific probes, analysis by hybridization with species-specific probes, analysis by restriction enzyme digestion, or by sequencing.by restriction enzyme digestion, or by sequencing.

Classical PCR methods are now replaced with real-Classical PCR methods are now replaced with real-time PCR assays.time PCR assays.

They can be used to quantify the DNA or RNA content They can be used to quantify the DNA or RNA content in a given sample.in a given sample.

In contrast to conventional PCR, real-time PCR In contrast to conventional PCR, real-time PCR requires less manipulationrequires less manipulation

Is more rapid . Is more rapid .

Is highly sensitive and specific. Is highly sensitive and specific.

Provides quantitative information. Provides quantitative information.

2.Restriction fragment length polymorphisms2.Restriction fragment length polymorphisms

Fact - the genomes of even closely related pathogens Fact - the genomes of even closely related pathogens are identified by variation in sequence. are identified by variation in sequence.

Steps - Isolation of target pathogen, Steps - Isolation of target pathogen,

- Extracting DNA or RNA (with subsequent - Extracting DNA or RNA (with subsequent

reverse transcription to DNA) reverse transcription to DNA)

- Digesting the nucleic acid with one of a - Digesting the nucleic acid with one of a

panel of restriction enzymes. panel of restriction enzymes. Separation of the individual fragments of DNA by gel Separation of the individual fragments of DNA by gel

electrophoresis electrophoresis Visualization by staining with ethidium bromide.Visualization by staining with ethidium bromide. Ideally each strain will reveal a unique pattern, or Ideally each strain will reveal a unique pattern, or

fingerprint. fingerprint. A good example of the application - differentiation of A good example of the application - differentiation of

rabies virus biotypes from dog.rabies virus biotypes from dog.

RFLPRFLP

GGATCCCCTAGG

A modification to the basic RFLP technique A modification to the basic RFLP technique - - Incorporation of PCR as a preliminary step to amplify Incorporation of PCR as a preliminary step to amplify

a specific region of the genome.a specific region of the genome. Amplified DNA serves as the template DNA for the Amplified DNA serves as the template DNA for the

RFLP technique.RFLP technique. This new combination (PCR-RFLP) offers - greater This new combination (PCR-RFLP) offers - greater

sensitivity for the identification of pathogens sensitivity for the identification of pathogens Especially useful when the pathogen are in small Especially useful when the pathogen are in small

numbers or is difficult to culture. numbers or is difficult to culture. Both RFLP and PCR-RFLP are immensely useful for the Both RFLP and PCR-RFLP are immensely useful for the

genotyping of strains of Cryptosporidiumgenotyping of strains of Cryptosporidium Examples in which the RFLP / PCR - RFLP techniques Examples in which the RFLP / PCR - RFLP techniques

are useful to differentiate between the genotypes – are useful to differentiate between the genotypes – the fungus the fungus Candida, Candida, - the bacterium - the bacterium Helicobacter Helicobacter pylori .pylori .

3.Diagnosis by DNA probes and DNA 3.Diagnosis by DNA probes and DNA Microarray technologyMicroarray technology

DNA probes are specific short sequence of single- DNA probes are specific short sequence of single- stranded DNA or RNA which are labeled and bind with stranded DNA or RNA which are labeled and bind with specific complementary strand of nucleic acid of specific complementary strand of nucleic acid of organism in question organism in question

Used in the detection of a segment of DNA sequence Used in the detection of a segment of DNA sequence (gene) in unknown organism.(gene) in unknown organism.

Used for the rapid identification of bacteria in Used for the rapid identification of bacteria in specimens e.g. specimens e.g. Hepatitis B virus, EB Virus, N. Hepatitis B virus, EB Virus, N. gonorrhoe.gonorrhoe.

In conventional DNA probing, the unknown DNA (or In conventional DNA probing, the unknown DNA (or RNA), is immobilized on a solid surface e.g. a filter.RNA), is immobilized on a solid surface e.g. a filter.

The known DNA ( labeled probe )is in the liquid phase The known DNA ( labeled probe )is in the liquid phase and is applied to the target.and is applied to the target.

The target can be nucleic acids extracted from clinical The target can be nucleic acids extracted from clinical material or cultured cells material or cultured cells

It is then either - (a) added to filters (a dot or slot blot)It is then either - (a) added to filters (a dot or slot blot)

or or

(b) transferred to a filter(b) transferred to a filter

after gel electrophoresis. after gel electrophoresis. If the amount of pathogen in a clinical sample is too low If the amount of pathogen in a clinical sample is too low

for detection , one can amplify the nucleic acid by PCRfor detection , one can amplify the nucleic acid by PCR

In order to visualize a probe bound to its target, the In order to visualize a probe bound to its target, the probe can be labelled with a radioactive nucleotideprobe can be labelled with a radioactive nucleotide

In situIn situHybridizationHybridization

Microarray technologyMicroarray technology

In microarray diagnosis, the known DNA ( large In microarray diagnosis, the known DNA ( large oligonucleotides or complementary DNA) are oligonucleotides or complementary DNA) are immobilized on a glass slide, and the unknown DNA immobilized on a glass slide, and the unknown DNA

( labeled probe ) is in the liquid phase.( labeled probe ) is in the liquid phase.

A microarray is so-called because it consists of A microarray is so-called because it consists of 20,000 or more different known DNAs, each DNA 20,000 or more different known DNAs, each DNA being spotted onto glass slides, to form the array. being spotted onto glass slides, to form the array.

Each spot is only around 10 μm in diameter. DNAs Each spot is only around 10 μm in diameter. DNAs complementary to the selected genes of pathogens complementary to the selected genes of pathogens can be used to make the arrays . can be used to make the arrays .

In microarray probing , the probe is made from the In microarray probing , the probe is made from the samplesample

Nucleic acid is extracted from a sample and an PCR is Nucleic acid is extracted from a sample and an PCR is performed using random oligonucleotide primers. performed using random oligonucleotide primers.

Part of all the nucleic acids in the sample (– both of host Part of all the nucleic acids in the sample (– both of host and pathogen origin ) are amplified. and pathogen origin ) are amplified.

These PCR products are labelled with a fluorescent dye These PCR products are labelled with a fluorescent dye and applied to the microarray. and applied to the microarray.

Under optimized conditions , only the DNA derived from Under optimized conditions , only the DNA derived from the pathogen will bind to the DNA on the glass slide.the pathogen will bind to the DNA on the glass slide.

If one is interested in detecting only a particular If one is interested in detecting only a particular pathogen or group of related pathogens, then pathogen or group of related pathogens, then pathogen-specific oligonucleotides can be used to pathogen-specific oligonucleotides can be used to amplify these within the sample for probe production.amplify these within the sample for probe production.

Molecular diagnosisMolecular diagnosis MeritsMerits Reduce reliance on Reduce reliance on

cultureculture FasterFaster More sensitiveMore sensitive More definitiveMore definitive More More

discriminatingdiscriminating Techniques Techniques

adaptable to all adaptable to all pathogenspathogens

DemeritsDemerits Technically Technically

demandingdemanding Relatively Relatively

expensiveexpensive Can be too Can be too

sensitivesensitive Provides no Provides no

information if information if results are results are negativenegative

Future of Molecular Diagnostic TechniquesFuture of Molecular Diagnostic Techniques

Rapid diagnosis will result in decreased cost.Rapid diagnosis will result in decreased cost.

Example: Mycobacteria - quick diagnosis - no need Example: Mycobacteria - quick diagnosis - no need for expensive laboratory isolation.for expensive laboratory isolation.

Increased specificity and sensitivity of molecular Increased specificity and sensitivity of molecular testing will become the standard of practice in testing will become the standard of practice in immunology and microbiology.immunology and microbiology.

Testing will become more rapid as assays are Testing will become more rapid as assays are automated which will also bring down the costs.automated which will also bring down the costs.

THANK YOUTHANK YOU