Which Sample Type Should I Choose?
Understanding the difference between blood, urine, and swab tests helps you choose the right STI screening package. Each sample type detects different infections.
The Key Principle
Different STIs live in different parts of your body. Blood-borne infections (HIV, Syphilis, Hepatitis) can only be detected through blood tests. Local infections (Chlamydia, Gonorrhoea) are found where the infection occurs – tested via urine or swabs. For complete peace of mind, we recommend combining sample types.
Blood Tests
Venous blood draw • Results in 1 day
What Blood Tests Detect
Blood tests detect infections that spread through your bloodstream. These infections may not show symptoms for months or years, but can be detected through antibodies or antigens in your blood.
HIV 1 & 2
4th generation test detects both antibodies and p24 antigen. Accurate from 4 weeks post-exposure.
Syphilis
Detects all stages of syphilis infection. Can identify past or current infection.
Hepatitis B
Tests for HBsAg surface antigen. Important if unvaccinated or vaccine status unknown.
Hepatitis C
Antibody screening for HCV. Essential for anyone with blood-to-blood contact history.
When to Choose Blood Tests
- You've had unprotected sex with a new partner
- Starting a new relationship and want complete clearance
- You have multiple sexual partners
- History of IV drug use or needle sharing
- Annual routine screening as part of sexual health maintenance
Our Blood Test Packages
Blood tests have a "window period" – time needed for antibodies to develop. HIV: 4 weeks, Syphilis: 3 weeks, Hepatitis: 6 weeks. Test too early and you may get a false negative.
Urine Tests
Non-invasive sample • Results in 2 days
What Urine Tests Detect
Urine tests detect bacterial infections in your urogenital tract. They're completely non-invasive and highly accurate, especially for men. PCR technology amplifies even tiny amounts of bacterial DNA.
Chlamydia
The most common bacterial STI in the UK. Often symptomless but can cause serious complications if untreated.
Gonorrhoea
Highly contagious bacterial infection. Increasing antibiotic resistance makes early detection crucial.
Mycoplasma Genitalium
Emerging STI that's becoming more common. Can cause urethritis and PID in women.
Ureaplasma
Often found alongside other infections. May cause urinary symptoms and fertility issues.
When to Choose Urine Tests
- Men – urine is the primary recommended sample type
- You prefer non-invasive testing without swabs
- You have urinary symptoms (burning, discharge, frequency)
- Quick screening without physical examination
Urine is the gold standard for male STI testing. It's just as accurate as urethral swabs but far more comfortable. Make sure not to urinate for at least 1 hour before your test for best results.
Our Urine Test Packages
Provide a "first-catch" urine sample (first part of your stream). Don't urinate for 1+ hour before. Our clinic provides private facilities and sterile containers.
Swab Tests (PCR)
Site-specific detection • Results in 2-6 days
What Swab Tests Detect
Swab tests collect cells directly from the infection site, making them the most accurate method for detecting STIs. For women, vaginal swabs are the gold standard. Swabs can also test throat and rectal sites.
All Bacterial STIs
Chlamydia, Gonorrhoea, Mycoplasma, Ureaplasma, Trichomonas – detected at the infection site.
Herpes (HSV 1 & 2)
Best detected by swabbing active lesions or sores. PCR identifies the viral DNA directly.
Bacterial Vaginosis
Vaginal swab detects the bacterial imbalance. Common cause of discharge and odour.
Candida (Thrush)
Yeast infection confirmation. Identifies the specific Candida species for targeted treatment.
Types of Swab Tests
Vaginal / Cervical Swabs
The most accurate sample type for women. Self-collected vaginal swabs are just as accurate as clinician-collected cervical swabs and more comfortable.
Throat Swabs
Detects pharyngeal gonorrhoea and chlamydia from oral sex. Often symptomless but can transmit infection to partners.
Rectal Swabs
Essential after receptive anal sex. Chlamydia and gonorrhoea can infect the rectum without symptoms.
Vaginal swabs are more accurate than urine for detecting STIs in women. Our packages with "PCR Swab" in the name are specifically designed for women. Self-collection is available in a private room – quick and painless.
Our Swab Test Packages
All our swab tests use gold-standard PCR (Polymerase Chain Reaction) technology. This amplifies DNA to detect even tiny amounts of infection – over 99% accuracy.
Sample Type Comparison
At-a-glance comparison of all sample types
🩸Blood | 🧪Urine | 🔬Swab | |
|---|---|---|---|
| HIV | ✓ | – | – |
| Syphilis | ✓ | – | – |
| Hepatitis B & C | ✓ | – | – |
| Chlamydia | – | ✓ | ✓ |
| Gonorrhoea | – | ✓ | ✓ |
| Mycoplasma / Ureaplasma | – | ✓ | ✓ |
| Trichomonas | – | ✓ | ✓ |
| Herpes (HSV) | ○ | – | ✓ |
| Bacterial Vaginosis | – | – | ✓ |
| Candida (Thrush) | – | – | ✓ |
| Best for | Everyone | Men | Women |
Still Not Sure Which to Choose?
Our clinical team can help you select the right package based on your situation, symptoms, and exposure history. Book a consultation or try our quick triage tool.