Cytomegalovirus – Quantitative RT-PCR:
Why Cytomegalovirus (Qualitative) RT-PCR Test?
CLINICAL INFORMATION
CMV is a virus that belongs to the herpes family and hence like other herpes infections CMV can cause latent manifestations (recurrence). It usually affects young adults (adolescent age group) and/or children. Usually, the primary infection (exposure) resolves by itself – mostly Self-Limiting. The virus can infect by handling or exchanging body fluids such as saliva, blood, urine, breast milk, semen etc. In pregnant women, CMV infection (the most common congenitally acquired virus that affects the developing fetus and the newborns) can cause serious harm to the developing fetus and can manifest in immune-compromised patients such as HIV/AIDS, with a weak immune system. CMV usually remains silent (asymptomatic) or mild symptoms, but it can also manifest with some signs and symptoms (clinical manifestations) such as prolonged fever, fatigue, loss of appetite, muscle and joint pain, stiffness, headache, sore throat, swollen lymph nodes, swollen liver and spleen, eye infection (inflammation of the retina), GI manifestations – diarrhea & abdominal pain, Respiratory manifestations – pneumonia with non-productive cough and shortness of breath, CNS – encephalitis, immune system depression leading to secondary infections eg. Fungal infections, complications in pregnancy eg. Abortions, stillbirth etc. while in newborn it manifests with manifestations such as anaemia, jaundice, seizures, developmental problems and/or with congenital abnormalities – born with birth defects such as a baby born with small head, dwarfism, disproportionate body growth etc. CMV being an opportunist infection is more likely to coexist along with certain pathologies such as pneumonia, hepatitis, GI diseases/disorders etc.
PCR – Polymerase Chain Reaction (PCR) technology (involving 3 main stages, denaturation, annealing and elongation), is very sensitive used in medicine as well as research for processing DNA sequencing. Due to its accurate application, it is also applied in the diagnostic molecular test that analyzes the given sample specimen for its source of genetic material (DNA, RNA –known as templates) for identifying microbial pathogen – detection and quantification in the body (given sample specimen). Suitable reagents such as template, nucleic acids (A, T, G, C) i.e dNTPs, primers, buffers (to ensure right condition for reaction), enzymes such as DNA Polymerase or RNA Polymerase, magnesium etc, are added and fed into the PCR machine known as thermal cycler (repeated thermal heating and cooling). This test involves the extraction of genetic material by isolation and amplifies the genetic material (DNA Cloning) present in the sample specimen to many folds by replication. Thus the amplified sample specimen detects and reads the signal and test results are interpreted as positive or negative. Therefore PCR application in genetic testing is performed to detect pathogenic DNA. This technique is used both for qualitative and quantitative analysis. Further, the amplified test specimen is subjected to electrophoresis for studying the size of DNA fragments i.e quantitative/qualitative analysis. RT-PCR: Reverse Transcriptase PCR or RT-PCR allows the use of RNA as a template (since some viruses contain only single-stranded RNA instead of DNA). An additional step allows the use of RNA as a template (RNA is transcribed using the enzyme RNA Polymerase into its complementary DNA – cDNA, which is RNA-DNA hybrid), which is then amplified, detected and quantified for test results. Cytomegalovirus (CMV)-RT PCR: Since CMV DNA load is an independent marker of CMV disease diagnosis is performed using Cytomegalovirus (CMV)-RT PCR and moreover there is increasing evidence of developing cytomegalovirus (CMV) disease in AIDS patients, quantitative Cytomegalovirus (CMV)-RT PCR is applied. Qualitative analysis is usually performed for assessment of purity (eg. Detection of a single band or a peak in PAGE revealing specific protein).
General Instructions:
Sample Requirement: Specimen - Blood sample collected from the vein. Test Preparation: None.
NOTE - Sample for specimen collections may vary based on the patient’s condition/cases according to the patient’s presenting complaints/signs or symptoms:
SPECIMEN REQUIREMENT (Special or Rare Cases) - As instructed and guided by Physician / Clinician / Pathologist / as per Laboratory’s requirements, according to procedures and protocols.
This Multi-Specialty Clinical Referral Laboratory RTDIAGNOSTICS provides precise and accurate tests with an extensive range of testing services to the medical centres to help in the diagnosis and identification of pathology in the test specimens for infectious diseases and also to evaluate the function of organ systems of the patient. It prevents further complications and helps to stabilize and restore health to near normalcy at the earliest without delay.
