Advantages and Disadvantages of Molecular Diagnostic Techniques PDF

Advantages and disadvantages of different molecular diagnostic techniques Advantages and disadvantages of different molecular diagnostic techniques PCR : Advantages: -Suitable for the detection of wide variety of pathogens with various modifications. - Suitable for a wide variety of spe...

Advantages and disadvantages of different molecular diagnostic techniques Advantages and disadvantages of different molecular diagnostic techniques PCR : Advantages: -Suitable for the detection of wide variety of pathogens with various modifications. - Suitable for a wide variety of specimen materials. - In comparison to antibody or antigen detection far more sensitive and specific. Disadvantages: - Specimen contamination will lead to false-positive results. - More expensive than serological methods. - Requires quality control.  Advantages and disadvantages of different molecular diagnostic techniques Fluorescence in situ hybridization (FISH): -Used for detection of specific DNA sequences or genes [regions] on chromosomes. - At metaphase stage the cells fixed on the slide and then treated with mild detergent [causes cell lysis] and alkali [convert dsDNS into ssDNA. - Prepare fluorescence probe [labeled with dye] by amplifying known sequence by using pcr - specificity of FISH probes achieved? Probes are designed for specific chromosomes or chromosomal regions Advantages and disadvantages of different molecular diagnostic techniques - The probe is added to the sample allow to hyperdize to complementary DNA sequence. - The probe can use different fluorescence dye if using multiple DNA sequences in chromosome Advantages and disadvantages of different molecular diagnostic techniques - After hyperdization the samples are washed to remove un-bound probes, then sample visualized under fluorescence microscope. - The gene that undergone amplification, duplication or deletion can easily be detected. Advantages and disadvantages of different molecular diagnostic techniques Advantages: - Allows the detection of nucleic acid directly from the sample without prior nucleic acid amplification. - Low cost - Laboratory contamination of the sample is not an issue - -Usually very specific Disadvantages: - Poor sensitivity -Screening of slides slow, unless an expensive automated microscope is available Advantages and disadvantages of different molecular diagnostic techniques Microarrays: Advantages: - Can detect both nucleic acids and antibodies - Very good sensitivity - Ability to detect several pathogens simultaneously Disadvantages: -Too expensive to be adapted for routine diagnostics - Usually requires nucleic acid amplification prior to analysis Advantages and disadvantages of different molecular diagnostic techniques What are molecular diagnostic techniques for cancer? Sequencing: - Next-generation sequencing (NGS)[Tumor sequencing test] allow for thorough genomic profiling of cancer. In the age of precision oncology, in which treatment plans are customized based on the unique genetic composition of each patient's tumor. - Biopsies - genetic tests - biomarker tests Advantages and disadvantages of different molecular diagnostic techniques biomarker tests: -A laboratory method that uses a sample of tissue, blood, or other body fluid[ urine, sliva] to check for certain genes, proteins, or other molecules that may be a sign of a disease or condition, such as cancer. Examples: -HER2 in breast cancer or -EGFR in lung cancer Advantages and disadvantages of different molecular diagnostic techniques -A tumour marker test on its own is not enough to screen for or diagnose cancer. Tumour marker test results should be combined with: 1. a thorough medical history 2. a physical exam 3. other lab tests Advantages: tumour marker test is being used to monitor how treatment is working -If tumour marker levels decrease or return to normal, it may mean that treatment is working. - An increase in tumour marker levels may mean the cancer is not responding to treatment, is growing or has come back (recurred). A slight increase may not be significant. - Chemotherapy treatment can cause a temporary increase in tumour marker levels. This happens because chemotherapy causes cancer cells to die quickly and release large amounts of the tumour marker. Advantages and disadvantages of different molecular diagnostic techniques Disadvantages: - Some tumour markers can be high in people who do not have cancer. - Some tumour markers are specific to a particular type of cancer, while others may be elevated in many types of cancer. - Tumour marker levels may not rise until the cancer worsens. This is not helpful for finding cancer early or finding out if cancer has come back after treatment.