COVID Biomarker
Collection Type: Throat Swab, Nasal Swab
Related System: COVID
COVID RT‑PCR (reverse transcription polymerase chain reaction) is a molecular test that detects SARS‑CoV‑2 viral RNA in respiratory specimens (commonly nasopharyngeal/oropharyngeal swabs, nasal swabs, or saliva). The test measures presence not live virus and is used to diagnose current (acute) COVID‑19 infection. It is ordered when there are symptoms such as fever, cough, shortness of breath, loss of taste or smell, sore throat, or after known exposure, and for screening before procedures or travel. Results can vary with timing of illness (earlier and peak phases give higher positivity), sample type and quality, and host factors: children and adults may have similar peak viral loads, while older or immunocompromised patients can have longer periods of detectable RNA.
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Symptom CheckerNegative Not detected (No SARS‑CoV‑2 RNA detected)
Q: What is RT-PCR for COVID?
A: RT‑PCR for COVID is a laboratory test that detects SARS‑CoV‑2 genetic material. A nasal or throat swab collects viral RNA, which is converted to DNA (reverse transcription) and amplified by PCR to identify infection. It’s highly sensitive and specific when performed correctly, used to diagnose active infection. Results take hours to days; a positive result indicates viral genetic material, not necessarily infectiousness.
Q: What is the difference between PCR and RT-PCR?
A: PCR (polymerase chain reaction) amplifies DNA sequences by repeated thermal cycling and DNA polymerase, producing many copies of a target DNA fragment. RT‑PCR (reverse transcription PCR) first converts RNA into complementary DNA (cDNA) using reverse transcriptase, then amplifies that cDNA—allowing detection of RNA targets (such as viruses or gene expression). RT‑PCR can be used for real-time quantification.
Q: What does a positive RT-PCR test mean?
A: A positive RT‑PCR test detects viral genetic material in a respiratory sample, indicating current infection or recent presence of the virus. It is highly sensitive, but can sometimes detect non‑viable viral fragments after recovery and may not always mean infectiousness late in illness. Clinical context and timing matter. Follow public health advice: isolate, inform contacts, and seek medical guidance as needed.
Q: What does the RT-PCR stand for?
A: RT-PCR stands for Reverse Transcription Polymerase Chain Reaction. It is a laboratory method that first converts RNA into complementary DNA (reverse transcription) and then amplifies specific DNA sequences (polymerase chain reaction) to detect and quantify viral genetic material. Widely used for diagnosing RNA viruses such as SARS‑CoV‑2, it is highly sensitive and specific when performed with proper protocols and equipment.
Q: What is the cost of a PCR test?
A: PCR test costs vary widely by country and setting. In India they typically ranged about ₹400–₹2,500; in the UK NHS testing is free for eligible people while private tests cost roughly £50–£150; in the US costs can be free with insurance or public programs, or about $50–$200+ for uninsured/private testing. Prices depend on location, provider, and coverage.
Q: What is PCR used for?
A: PCR (polymerase chain reaction) is used to amplify small amounts of DNA/RNA for detection and analysis. Clinically, it diagnoses infections (e.g., COVID-19, influenza, bacterial pathogens), detects genetic mutations, and screens for inherited disorders. In forensics and paternity testing it identifies individuals, while in research and biotech it enables cloning, sequencing, and quantitative assays (qPCR) to measure pathogen load or gene expression.