Infectious Disease Diagnostics by PCR. Prices, Reviews, Ratings
Relevance of PCR Diagnostics
PCR is a highly sensitive diagnostic method, delivering precise results shortly after sample collection. It identifies pathogens without labor-intensive microbiological techniques and detects them during the incubation period, before symptoms appear, enabling timely treatment. PCR is particularly valuable in urology and gynecology for diagnosing sexually transmitted infections.
Beyond medical diagnostics, PCR is used in:
- criminal investigations;
- paternity testing;
- personalized medicine;
- gene cloning;
- mutagenesis.
In forensics, PCR determines genetic fingerprints, comparing crime scene material (blood, semen, urine, saliva, hair, epithelial cells) with a suspect’s sample.
Paternity is established through multiple comparisons, leveraging unique genetic information.
In personalized medicine, pre-genotyping identifies receptor presence and drug sensitivity, simplifying medication selection for patients with genetically influenced drug responses.
Gene cloning via PCR produces numerous identical DNA segments for genetic engineering. Mutagenesis using PCR is widely applied in experimental medicine, breeding, and pharmaceutical production.
PCR Diagnostic Process
The treating physician informs patients of specific preparation requirements, but general guidelines apply to all undergoing PCR.
Testing should occur before starting antibiotics. For 2–3 days prior, avoid sexual activity, local contraceptives, antimicrobial vaginal suppositories/tablets, and douching. Allow at least three days after colposcopy, gynecological exams, or vaginal ultrasound. Mid-cycle is optimal for swab collection. Both men and women should refrain from urinating for three hours before testing.
PCR diagnostics begin with a specialist collecting a sample, placed in a small container with saline and sent to a PCR lab.
PCR involves amplification—creating numerous DNA copies—based on complementarity. DNA comprises four nucleotides (adenine, thymine, guanine, cytosine), with adenine pairing only with thymine and guanine with cytosine due to chemical structure. Each organism’s DNA is unique, allowing identification from a small fragment.
Laboratory testing occurs in stages:
- DNA extraction;
- DNA fragment amplification;
- detection of amplified DNA products.
Simplified, PCR diagnostics heat the target DNA matrix to separate its double helix into single strands (denaturation).
Next, during annealing, the temperature is lowered, and primers—short nucleic acid fragments—attach to the chain’s start and end, marking the segment for amplification.
Polymerase enzymes then build the missing chain segment, yielding a typical double-stranded nucleic acid molecule via replication, following complementarity rules (elongation).
DNA identification follows, using electrophoresis or labeled primers. In electrophoresis, DNA strands are linearized and migrate in an electric field through agarose gel from the negative cathode to the positive anode. Longer strands move slower, and size is compared to a standard. Quantity is assessed by glow intensity after staining.
With labeled primers, a chromogen is added post-PCR, changing color upon enzyme interaction to indicate pathogen presence.
Beyond standard PCR, labs offer variants:
- Nested PCR (using two primer pairs);
- Inverse PCR (amplifying from a central known segment outward);
- Reverse transcription PCR;
- Asymmetric PCR (copying one strand);
- Quantitative PCR (measuring product amount with labeled primers);
- Stepwise PCR (varying annealing temperature);
- In-gel PCR (producing DNA colonies on acrylamide gel);
- Long-fragment PCR;
- Polymorphic DNA PCR (distinguishing genetically similar organisms).
Indications
PCR diagnostics are indicated for:
- external symptoms of sexually transmitted infections;
- unprotected sex with a new partner;
- chronic urogenital inflammation (to identify causative infections);
- complicated pregnancies;
- preterm births or miscarriages often due to infection;
- infertility-linked infections;
- assessing antibiotic sensitivity;
- monitoring treatment efficacy.
Test Interpretation
A negative PCR result indicates no infection traces in the sample, confirming the patient’s health. A positive result shows infection traces.
Occasionally, a positive result occurs without active infection, indicating “healthy carriage,” which neither requires nor responds to treatment.
Prices and Clinics
PCR diagnostics are conducted by qualified venereologists in modern medical centers. Use the online service to select a suitable clinic.
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