Testing methods, explained
How Tota compares
Not all microbiome tests look for the same thing.
Why test prices vary so much and what you're actually paying for
If you've landed on this page whilst comparing different urine tests, you've probably already spotted something confusing. A quick urine test can cost as little as £15–£20. Other microbiome tests on the market cost a few hundred pounds (around the same as Tota). Some cost even more. And the prices don't obviously line up with what each test actually finds. That's because price doesn't tell you what a test is looking for or what the method does, and that's what this article explains.
A cheap, fast test: a pharmacy dipstick or a standard urine culture sent to a lab, is inexpensive because it's built to check for a short, common list of likely causes, most often the single bacterium behind a typical first-time UTI. That's a genuinely well-suited test for a lot of people, a lot of the time (there's more on when standard testing is enough later on this page).
Many other tests on the market, at a range of price points, use a method called PCR
PCR tests use a technique that checks a sample against a fixed list of organisms' DNA. PCR is genuinely very good at finding what it's built to find, quickly and sensitively. But it can only ever report on the organisms already on that list, and testing science has moved on since it became widely used: broader methods that don't rely on a fixed list are now available.
Other tests priced closer to Tota's £299 might use a method called 16S rRNA gene sequencing. It's broader than a dipstick or culture; it can pick up thousands of different bacteria rather than a handful, but it has real limits.
Firstly, it can’t look at your microbiome in the round. This is because 16S rRNA only looks at bacteria. To find yeast a different test has to be run in the lab. This means these tests might show you bacteria and yeasts, but they won’t add up to 100% of your microbiome. And it’s confusing when numbers don’t add up. Secondly, because this method reads on short stretch of DNA, it often can’t tell closely related bacterial species apart. And thirdly, it’s not fully quantitative which means you don’t know exactly how much bacteria is there. It uses a method called relative abundance which measures organisms in relation to other things, not how much is actually there. There's a full, plain-English explanation of this method further down the page.
Tota uses the most recent method of testing
Tota uses third-generation metagenomic sequencing, that reads all the DNA in a sample rather than one gene or a fixed list. It identifies both bacteria and fungi, to species level, across a reference range of more than 4,000 organisms. That's the difference the price reflects: not simply “more expensive,” but a meaningfully broader one.
We believe this kind of full-picture testing should be the standard way of understanding recurring or unexplained issues, not a premium add-on. It isn't yet widely available, which is a real part of why Tota exists. That said, a cheaper or narrower test isn't automatically the wrong choice: for a first, straightforward UTI, standard testing does its job well. The rest of this page explains, method by method, what each option actually finds, so wherever you land, the price makes sense in context.
You can't solve a problem you can't see.
Why does the testing method matter?
If you've ever had a urine test come back 'clear' while your symptoms didn't, that's often down to what the test was built to look for, not necessarily what's happening in your body.
Every microbiome or urinary test works by looking for something specific. What differs hugely, from one method to another is what that “something” actually is: a fixed shortlist of usual suspects or every bacteria present in the sample. The method a test uses decides what it's capable of finding before a single sample is even collected.
That matters because there isn't one universal line between “healthy” and “infected” that applies to everyone. The most commonly used cut-off for diagnosing a urinary tract infection (100,000 bacteria per millilitre of urine) was set in 1956, in a study designed to answer one specific question, in one specific group of women.
Yes, you read that right, 1956, over 70 years ago!
It was never intended as a general rule for everyone with symptoms. Later research found that people with clear UTI symptoms can have far fewer bacteria than that threshold and still have a real, treatable infection. A similar picture shows up with bacterial vaginosis (BV): the standard methods used to diagnose it only agree with each other somewhere between 40% and 85% of the time, depending on the study. In both cases, the definition of “infected” depends partly on which test is used, not only on what's happening in your body.
None of this means standard tests are wrong or pointless. For a straightforward, first-time infection, they usually do their job well (more on that below). It means that when standard results and real symptoms don't match up, the test's method, what it was designed to look for, is often the reason why.
What “normal” usually means
A “normal” or “negative” result usually means
nothing on that particular test’s list was found
not that nothing is present.
Different tests can have very different lists.
What is targeted testing?
When you go to your GP or pharmacist with a UTI, they'll typically do one of two things: prescribe antibiotics based on your symptoms alone or send a sample off to the lab for a standard urine culture. The lab will often then check the sample against a predetermined list of the usual suspects, decided in advance, rather than checking everything that could possibly be present.
Targeted testing works from a fixed, predetermined list of organisms decided in advance. PCR (polymerase chain reaction) tests are the clearest lab-based example: they check a sample against a specific set of DNA “fingerprints” (often up to around 20 organisms) and can detect even very small amounts of any organism on that list, quickly and reliably.
The trade-off is built into the method. A targeted test can only report on what it was told to look for. If the organism involved isn't on the list (even if it's clinically significant) a targeted test has no way of seeing it. Some reviews of UTI testing panels note that certain organisms linked to chronic symptoms are routinely left off standard panels altogether. Targeted tests can also pick up DNA from organisms that are no longer alive, which can sometimes suggest an active infection where there isn't one.
In plain terms
Think of a targeted test like being asked to check a house for a specific list of items. You'll find them quickly if they're there, but anything that is not on the list you will not find as you’re not looking for it.
What is non-targeted testing?
Tota uses non-targeted test and the Tota tests exist to give people a more complete picture than a fixed list can offer. Non-targeted testing doesn't start with a list at all. Instead of checking for specific, predetermined organisms, it reads whatever genetic material is present in the sample and reports back every bacteria and yeast it finds.
The benefit is breadth: nothing is excluded by design, because nothing was decided in advance. The trade-off is interpretation. A non-targeted test can return more information than a shortlist-based test and the wider scientific field is working out exactly what counts as a meaningful difference from a typical, healthy microbiome. More information is only useful once it's explained well, which is why how a result is reported matters as much as how it's generated.
In plain terms
If a targeted test is checking a house against a list of specific items, a non-targeted test is closer to walking through every room and writing down everything you find, whether or not it was on anyone's list.
We believe full-picture testing like this should be the standard. It isn't the default yet, which is part of why we built Tota.
Targeted vs. non-targeted testing, at a glance
How does Tota's approach compare to PCR or standard culture?
tota
Targeted tests (PCR / culture)
Reads every organism present in the sample, nothing decided in advance
Only checks a predetermined shortlist of usual suspects
Identifies bacteria and fungi in the same test
Usually bacteria-only; fungi need a separate test
Species-level detail, even for closely related organisms
Can struggle to tell closely related species apart
Reports absolute counts. Exactly how much of each organism is actually there
Often only tells you if an organism is present, not how much
Nothing excluded by design, so nothing is ruled out before you start
Anything not on the list is invisible to the test
Six broad approaches are used today to look at urinary and vaginal health, ranging from a two-minute strip test to full DNA sequencing. Each answers a different question, and each has a different “detection power”; how much of what's actually present in a sample it's capable of finding.
The main testing methods, explained plainly
Click any card to expand it and read the full explanation.
1. Dipstick testing
A colour-change strip for two chemical signals.
What it is: A short plastic strip, dipped into a urine sample, that changes colour if it detects two chemical signals: nitrite, a by-product of certain bacteria, and leukocyte esterase, a sign of immune cell activity.
How it works: A chemical colour-change reaction, read within about two minutes.
What it looks for: Two general signs that bacteria or immune activity may be present, not the organisms themselves.
Limitations: A negative dipstick isn't a clean bill of health. It misses around half of bacterial UTIs and is unreliable for several common bacteria. Guidance recommends against relying on dipsticks to diagnose UTI in people over 65, because they're too unreliable in that age group.
Why it matters: Useful as a quick first screen for straightforward, first-time symptoms in younger adults, but not designed to tell you which organism, if any, is involved, or to confidently rule an infection out.
2. Standard urine culture
The long-standing test for UTI (and the one used by most NHS labs).
What it is: Bacteria is grown on a plate in specific conditions.
How it works: sample is spread onto a growth medium in a petri dish and left to incubate for one to three days. Bacteria that grow in large enough numbers, under the specific conditions used, form visible colonies that the lab can identify and test against antibiotics.
What it looks for: Common, fast-growing bacteria; principally E. coli and a handful of others responsible for most straightforward UTIs.
Limitations: Anything that grows slowly, prefers low-oxygen conditions, or falls below the lab's reporting cut-off can be missed. Independent studies suggest standard culture misses around two-thirds of infection-causing bacteria overall, and around nine in ten in women with chronic UTI. It's also poorly suited to analysing the vaginal microbiome.
Why it matters: This matters less for a first, straightforward infection, and considerably more for chronic, recurrent or atypical cases
3. Expanded culture (EQUC)
Same technique as standard urine cutlure with larger volumes and grown for longer. Still only sees what grows.
What it is: The same basic culturing technique as standard culture, with the rules deliberately loosened.
How it works: Larger sample volumes, a wider range of growth media, both oxygen-rich and oxygen-poor conditions, and longer incubation. Designed to give harder-to-grow bacteria a chance to appear.
What it looks for: A much wider range of bacteria than standard culture, including species often found in recurrent and chronic infections.
Limitations: Still only detects organisms willing to grow under lab conditions. Fungi need entirely separate testing methods. It's slower and more expensive than standard culture.
Why it matters: A meaningfully more thorough option than standard culture for recurrent or unresolved cases, though still culture-based, with the same fundamental blind spot: it can only see what grows.
4. PCR / qPCR (a targeted DNA test)
Checks a sample against a fixed list of common organisms. Blind to anything off-list.
What it is: A laboratory technique that checks a sample against a fixed list of ~20 organisms.
How it works: It amplifies (“copies up”) the DNA of any listed organism that's present, even in tiny amounts, making it very sensitive to anything it's designed to detect. qPCR versions give a rough sense of how much of each organism is present.
What it looks for: A predetermined panel, typically up to around 20 organisms, sometimes more. Some panels also include fungi or antibiotic-resistance markers.
Limitations: Anything not on the list is invisible to the test, however clinically relevant it might be. It can also detect DNA from organisms that are no longer alive, which doesn't necessarily mean an active infection.
Why it matters: Fast and highly sensitive for known, likely suspects, but only ever as broad as its predetermined list.
5. 16S rRNA gene sequencing (a broad scan)
Reads one gene shared by all bacteria. Broader, but bacteria-only and limited species resolution.
What it is: A method considered a research gold standard for some time, though it's since become clear it has limitations.
How it works: It amplifies and then sequences one specific gene (the 16S ribosomal RNA gene) that exists, with small variations, in every bacterium.
What it looks for: A much wider range of bacteria than a PCR panel, with no fixed list.
Limitations: It's designed for bacteria only. Fungi need a separate test run in parallel. Because it reads only a short stretch of DNA, it often can't reliably tell closely related species apart, which matters in the vagina, where one Lactobacillus species can have very different implications for health than another. The amplification step can also over- or under-represent particular bacteria, and audits of the reference databases used have found meaningful error rates.
Why it matters: Broader than a fixed panel, but it only reads one short piece of DNA shared by all bacteria, not the organism's full genetic makeup. That means it can miss the difference between two very similar bacteria, it only detects bacteria (not fungi), and it can sometimes throw up background noise or false positives.Testing from most providers usually takes around 2 weeks.
In plain terms: Reading one gene is a bit like identifying someone by their surname. It tells you which family they belong to, but not always which individual member of that family you're looking at.
6. Third-generation metagenomic sequencing — Tota's method
Reads all microbial DNA directly. Bacteria and fungi, species-level, 4,000+ organism reference range, absolute counts.
What it is: The most complete DNA-based approach described here, and the method Tota uses.
How it works: Rather than amplifying and reading one gene, it reads all the microbial DNA present in a sample directly, using the most recent generation of sequencing technology.
What it looks for: Whatever is actually there, there's no predetermined list.
What it can find: Bacteria and fungi, identified to species level, across a reference range of more than 4,000 organisms, reported as absolute counts (how much of each organism is present) rather than proportions alone.
Limitations: Because nothing is excluded by design, results can include more information than a shortlist-based test would ever surface. Interpreting that information well, understanding what's typical, what's unusual, and when a difference is likely to matter, is an active, evolving area of science, and that responsibility sits with how a result is explained not just how it's generated.
Why it matters: It's the only method on this list that can return bacteria, fungi and (importantly) how much of each organism from a single sample, without deciding in advance what to exclude.
Why third-generation sequencing is different from 16S rRNA sequencing
These two are both DNA sequencing methods, and it's easy to assume they're roughly the same thing. The difference comes down to how much of the DNA each one reads, and that changes what each can tell you.
The benefits of third-generation metagenomic sequencing:
- Third-generation sequencing reads all the DNA, not one gene. 16S sequencing amplifies and reads a single bacterial gene. Third-generation metagenomic sequencing reads every fragment of DNA in the sample. Imagine having a long piece of string. 16S rRNA method would take a short section of the string and tell you what’s there, third-generation metagenomic sequencing would tell you every bacteria and fungi present along the whole string not just a small section.
- It sees more than bacteria. 16S can only identify bacteria. Metagenomic sequencing identifies bacteria and fungi in the same test, without needing separate methods in the lab.
- It can tell similar species apart. 16S reads a short section of DNA and often can't reliably distinguish closely related species. Metagenomic sequencing reads each organism's fuller genome.
- It avoids amplification bias. 16S chemically amplifies one gene before sequencing it, and the method used can over- or under-represent particular bacteria. Metagenomic sequencing doesn't rely on that same amplification step.
- It uses more complete reference data. Audits of public 16S reference databases have found a meaningful proportion of erroneous sequences. Metagenomic sequencing is checked against fuller reference genomes.
Testing method comparison at a glance
| Method | How it works | Targeted / non-targeted | Detects fungi | Breadth of information | Benefits | Limitations |
|---|---|---|---|---|---|---|
| Dipstick | Chemical colour-change strip for two signals | Signal-based (not organism ID) | No | Detects signals, not organisms | Fast (2 min), cheap, useful first screen | Misses ~half of bacterial UTIs; unreliable over 65 |
| Standard urine culture | Sample grown on agar 1–3 days; colonies identified | Targeted (only what grows) | No | ~20–30 species reliably identified | Reliable for common, fast-growing bacteria; shows antibiotic sensitivity | Misses ~67% of infection-causing bacteria overall; ~90% in chronic UTI |
| Expanded culture (EQUC) | Broader culturing: more media, more conditions, longer incubation | Targeted (still culture-based) | No (needs separate test) | ~100+ species | Catches much more than standard culture, incl. harder-to-grow species | Still only sees what grows; slower and costlier |
| PCR / qPCR | Amplifies DNA matching a fixed organism list | Targeted (fixed list) | If included on panel | ~20–50 organisms (panel-dependent) | Very sensitive for anything on its list; qPCR is semi-quantitative | Blind to anything off-list; can detect DNA from dead organisms |
| 16S rRNA sequencing | Amplifies + sequences one bacterial gene | Broader, but gene-limited & bacteria-only | No (separate ITS test needed) | ~3,000+ bacteria (database-dependent) | Wide bacterial detection with no fixed list | Bacteria only; limited species resolution; some bias/error risk |
| Third-gen metagenomic sequencing (Tota) | Reads all microbial DNA directly, no single-gene amplification | Non-targeted (no predetermined list) | Yes | More than 4,000+ organisms | Finds all bacteria and fungi in a sample, at species level. No fixed list. | Returns more information than a shortlist test; interpretation is an evolving science |
How Tota's approach works
Tota uses third-generation metagenomic sequencing on an at-home vaginal or urinary samples. Instead of checking a list of usual suspects, it reads the genetic material actually present and reports back the bacteria and fungi it finds, to species level, along with how much of each is there. Results are returned within two to five days of the sample reaching the lab, through a private online portal, in plain-English, and are shareable with a GP or other healthcare professional if you choose to.
Why Tota chose this approach
We built Tota around one belief: women deserve better answers than “everything looks normal.” Standard testing methods are genuinely well suited to a lot of situations. A first, straightforward UTI in an otherwise healthy adult, for instance, is usually caused by a single, common bacterium that standard culture identifies reliably. But standard methods are, by design, working from a shortlist. For people whose symptoms continue despite a “normal” result, whose infections keep recurring, or who are simply asking “what else might be here” rather than “is the usual suspect present”, a shortlist-based test can only ever answer part of the question because it wasn’t designed to look further.
Third-generation metagenomic sequencing was, to us, the method that best matched what our customers were actually asking for: not a faster version of the same shortlist, but a genuinely different starting point, one that doesn't decide in advance what to exclude.
What Tota's results can, and can't, tell you
How to choose the right test for you
Not every situation calls for the most thorough test available. For a first-time, straightforward UTI in an otherwise healthy adult, standard NHS testing works well for most people, most of the time.
It's worth considering a more thorough test when:
- Symptoms continue without a clear answer
- The infection or symptoms keep returning
- Fertility is part of the picture
- You're trying to understand what else might be present, not only whether the most common cause is there
If none of those apply to you, a standard test is a sensible place to start. If some of them do, a fuller picture may be a genuinely useful next step, and that's exactly the gap Tota was built to fill.
Ready to understand more?
Frequently asked questions
If a test from my GP came back normal, does that mean nothing's wrong?
Not necessarily. A “normal” or “negative” result usually means nothing on that particular test's list was found, not that nothing is present. Different tests look for very different things, so the same sample can produce different results depending on the method used. If your symptoms don't match a “normal” result, it's often because the test wasn't designed to see what's going on, not because you're imagining it.
What's the difference between targeted and non-targeted testing?
Think of a targeted test (like PCR) as checking a house for a specific list of items, quick and reliable for anything on that list, but blind to anything that isn't. A non-targeted test (like Tota) is closer to walking through every room and noting everything found, whether it was expected or not. Neither approach is “wrong”, they're designed to answer different questions.
Can Tota's test tell me if I have an infection?
Tota's test tells you which bacteria and fungi are present in your sample, and roughly how much of each. Not every organism detected is necessarily the cause of any symptoms you're experiencing, it doesn't diagnose an infection or any medical condition. That's a clinical judgement made by a healthcare professional.
Medical and scientific disclaimer: this page is for general information and educational purposes only. It does not diagnose, treat or rule out any medical condition. Tota provides information about the organisms present in a sample; it is not a medical device and is not a substitute for professional medical advice. Always speak to a GP or other qualified healthcare professional about symptoms, diagnosis or treatment.
