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Diagnostics on demand.
Providing you with simple, easy access to world-leading laboratories that deliver the broadest range of wellness focussed diagnostic testing services.
For health professionals and patients across the UK and around the world.

Frequently Asked Questions


Why does my report not show susceptibilities to parasites?

A stool test consists of submitting samples in a number of different tubes. One tube is sent to the lab to be cultured (bacteria & yeast), while others are sent to microscopy where they are viewed under a microscope (parasites). Susceptibility can only be done on cultured yeasts or bacteria. If there are no cultures of dysbiotic flora, your report will not show any susceptibilities for natural or prescriptive agents.

It is not possible to culture parasites: they are individual organisms. For this reason it is not possible to provide susceptibilities for them.

What are yeast and bacterial susceptibilities?

Growth based testing demonstrates susceptibility to pharmaceutical & natural agents. If dysbiotic bacteria or yeasts are cultured, they will be exposed to agents for their reactivity and their response measured, so you can plan your treatment or support accordingly.

Why is there no susceptibility testing for microscopic yeasts?

Doctor's Data (DD) will run susceptibility testing on dysbiotic bacteria when they are in the pink section, or on cultures of yeast of 1+ or above.  DD have 2 ways of assessing yeast.  From CULTURE (live yeast cells that have been grown) or from MICROSCOPY (dead yeast cells seen down a microscope).   Although they report on the dead yeast cells, they can only run sensitivities on ‘live’ cultures.  

Why does the report show microscopic yeast but not cultured yeast?

When you submit samples to the lab for testing, you do so in a number of tubes.  One tube has a fluid in which allows for bacteria/yeast to be preserved in transit to the lab and allow them to be cultured at the lab. The parasite tube has a fixative in it, which essentially kills but preserves everything that’s in it for microscopy.  If live yeast cells are not cultured no sensitivities can be done, but the microscopy may have revealed (dead) yeast cells.  

Why may there be disparity between mycology and microscopy?

Yeast may normally be present in small quantities in the skin, mouth, and intestine. When investigating the presence of yeast, disparity may exist between culturing and microscopic examination. Yeasts are not uniformly dispersed throughout the stool and this may lead to undetectable or low levels of yeast identified by microscopy, despite culture and identified yeast species. Conversely, microscopic examination may reveal a significant amount of yeast present, but no viable yeast cultured. Yeast may not always survive transit through the intestines. Nonviable diet derived yeast may also be detected microscopically. Consideration of clinical intervention for yeast detected microscopically should be made in the context of other findings and presentation of symptoms.

Can laxatives be taken during a stool test?

If your patient can still produce a regular bowel movement without the need for laxatives this is ideal, however for some patients this may not be possible. If they regularly use laxatives this can be viewed as their baseline and therefore it is still possible to carry out a test. Please note the laxative use must be factored into the interpretation of their results.

Permittable substances to induce a stool include prune juice, magnesium citrate and psyllium.

What are the optimal values for lactobacillus and Bifidobacterium in a Comprehensive Stool Analysis?

Ideally the levels should be 4+ for Bifidobacterium and at least 2+ for Lactobacillus.

Can I continue taking proton pump inhibitors (PPIs) while doing a stool test?

I You can continue taking PPIs while carrying out a Comprehensive Stool Analysis.

Can I send my stool sample via Royal Mail?

Stool samples can only be returned via courier as their volume exceeds the Royal Mail regulations for biological substances. The total sample volume / mass of diagnostic specimens in any parcel must not exceed 50ml/50g.

Do I have to freeze and return the ice pack sent with my Comprehensive Stool Analysis?

Yes, this will help to support the viability of your sample in transit. You should also freeze your sample in the white topped vial (only) for at least six hours.

How long can I keep my stool sample before shipping?

Your sample must be returned 7 days after the collection of your first sample.

If I am taking a Comprehensive Stool Analysis with 3-Day Parasitology do my samples have to be collected on consecutive days?

Ideally yes but for some people this may not be possible. Therefore, ensure you collect your samples within 7 days of collecting your first sample.

What should I do if I am taking a Comprehensive Stool Analysis with 3-Day Parasitology and I am unable to collect enough samples within the 7-day time frame?

If you are unable to produce enough samples we will adjust the type of test you have ordered. For example, if you ordered the 3-day test and you return 2 samples we will automatically downgrade your test.

How full do the sample tubes need to be for stool testing?

Please ensure you fill the tubes up to the line, including any liquid it contains. Take pieces of stool from different areas of the sample. Do not under or over fill as this may influence the outcome of your test.

What should I do if I forget to freeze the white topped tube in my Comprehensive Stool Analysis kit?

Unless you have requested a test for H. pylori, this will not affect the quality or viability of your sample. You can still return your completed test kit as normal.

What should I do if I contaminate my stool sample with urine?

Try to take the sample from the centre of your stool where it will be least contaminated. If you feel the sample is excessively contaminated, then please wait for a further bowel movement.

What happens if I cannot eat the recommended amount of fat prior to my stool test?

If you are following a healthy and balanced diet you should be able to reach the advised quantity of 60-100g of fat for 3 days prior to the test. If you are following a low-fat diet for medical reasons, then your practitioner should be aware of this and will factor it into the interpretation of your results.

Can I carry out a stool test while on my period?

Ideally it is best to wait until you have finished your period as the risk of contaminating your stool sample with blood is very high and this may influence your results.


Is it possible to complete a DUTCH Test if my periods are irregular?

It is difficult to know exactly when to do this test when a cycle is changeable.  The goal of doing it in the peak of the luteal phase is important for the progesterone measurement – to get it at its peak – which, in a ‘regular, 28 day’ cycle is between days 19-21.  Either side of that ‘peak’ the progesterone could appear to be ‘low’ if the sample is taken at the wrong time, although still within the luteal phase. The oestrogen metabolism information would still be valid, and the testosterone and adrenal markers would most likely not be impacted.    

One way of establishing when to do the test is via ovulation kits (available online or from a chemist) and then, on a positive test, wait for 6/7 days to collect the samples.  The ‘theory’ is that a bleed will start 14 days after ovulation, so the peak of the luteal phase should be 7 days before you get your next period, so 7 days after ovulating.  You will appreciate that this can be changeable under certain conditions. There are other signs to look out for such as changes in cervical mucous, basal body temperature and possibly ovulation pain. More information can be found by clicking here.  

The lab will accept samples collected within 10 and 4 days of the next period starting. So, if a patient collects her samples on, for example, day 25, and then has a 27-day cycle, then that wouldn’t be worth submitting.

We would suggest patients with irregular periods to follow the above guidelines, collect their samples when appropriate, freeze them, and wait for their next period to start. We can gauge whether she’s in that 10-4 day window (counting back from when her next period started).

Is it possible to complete a DUTCH Test if I am breastfeeding?

If a patient is breastfeeding and not currently cycling, then all hormones will, as expected, be low. Although choosing if or when to test is of course down to the practitioner, it is better to wait for the patient’s periods to return. You may like to wait for 2-3 cycles before testing. While waiting for the patient’s cycles to normalise a good interim option is a DUTCH Adrenal Test.

When is it possible to take a DUTCH Test after stopping breastfeeding?

If a patient is breastfeeding and not currently cycling, then all hormones will, as expected, be low. Although choosing if or when to test is of course down to the practitioner, it is better to wait for the patient’s periods to return. You may like to wait for 2-3 cycles before testing. While waiting for the patient’s cycles to normalise a good interim option is a DUTCH Adrenal Test.

How long are the DUTCH strips viable after testing?

5 days or 6 months in the freezer.

Is it possible to take a DUTCH Test while using a coil?

The copper IUD, also known as the Paragard, is not made up of any hormones therefore you can test on the typical day 19, 20 or 21 of an average 28-day cycle as the instructions request. However, the Mirena IUD contains synthetic progesterone known as progestin. For those women who still have a cycle with the Mirena, it can partially suppress ovulation in some women which will make progesterone levels sub-optimal or outright low. The progestin may also increase the oestrogens due to its oestrogen effect. The DUTCH test is a very good way to see if the Mirena is suppressing hormones.

The progestin in the Mirena often makes the lining of the uterus very thin to almost non-existent. As a result, some women do not bleed when it’s time to have their period. This can make it difficult to determine exactly what day of their cycle they are on. There are physical signs to look out for such as changes in cervical mucous, basal body temperature and possibly ovulation pain. More information can be found by clicking here.

If you need further guidance on this please call the lab to discuss your options if you are doing sex hormones as part of your testing. Remember DUTCH testing is very specific (accurate) so synthetic progestins found in hormonal IUDs are NOT seen by our testing methods.

If you are only doing the adrenal test, you can collect as instructed by your healthcare provider.

Is it possible to use DUTCH testing while using melatonin supplements?

Using melatonin will affect the results of a DUTCH test. If you are wanting a baseline measurement, and they’ve been on it for more than 3 months, we would recommend they take a week off. It may be possible to avoid supplementation for only 3 days to get the baseline but it might not. If you feel the detriment of being off the Melatonin is worse than finding the baseline, you can just test with the supplementation and factor this into your interpretation.

Is it possible to use DUTCH testing after a hysterectomy?

Ideally wait at least 2 weeks post-surgery before DUTCH testing.

Can I use a DUTCH Test if I do not have a cycle?

If you do not have a cycle or you are postmenopausal you can test on any day of the month.

Can I use a DUTCH Test if I am using the contraceptive pill?

We don’t generally recommend the hormone part of the DUTCH test when taking the oral contraceptive pill because the metabolism of oestrogen is sometimes misleading. It may look ‘normal’ but only because so very little endogenous oestrogen is being reported because the test does not pick up synthetic hormone. However, if you have someone with very low oestradiol, they favour 4OH and their methylation is low this is a huge concern as they are on exogenous hormones and they are likely going down carcinogenic pathways as well. Unfortunately, this is hard to view and interpret when on the pill. It is also interesting to note that the progestin only pill can lower both progesterone and oestrogen.

Can I use a DUTCH Test if I postmenopausal?

If you do not have a cycle or you are postmenopausal you can test on any day of the month.

Which day should men carry out their DUTCH Test?

Men can collect their samples on any day.

When can you carry out a DUTCH test after pregnancy?

If a patient is postnatal and breastfeeding and not currently cycling, then all hormones will, as expected, be low. Although choosing to test is of course down to the practitioner, it is better to wait for the patient’s periods to return. While waiting for the patient’s cycles to normalise a good interim option is a DUTCH Adrenal Test. If a patient is not breastfeeding similarly it is preferable to wait for her normal periods to resume over a course of 2-3 cycles.

Why are there food and supplement restrictions prior to using the DUTCH Complete, DUTCH Plus and DUTCH Cycle Mapping?

The tests include six organic acids which cannot be properly assessed unless a short list of food and supplements are avoided before testing. For DUTCH Cycle Mapping avoid the following foods as much as possible for 72 hours before collecting the LAST 4 SAMPLES ONLY: avocado, bananas, eggplant, kiwi, butternuts, pecans, walnuts (and associated nut butters), pineapple (and pineapple juice), plantains, and plums. If you happen to consume some of these foods, please make a note on your requisition form. For DUTCH Complete and DUTCH Plus avoid the above foods for 72 hours before collection. Supplements such as 5-HTP, tryptophan, SAMe, Tyrosine, Quercetin and St. John’s Wort should also be avoided. For a comprehensive list please refer to your test kit instructions.


Why should I test for SIBO?

There are many reasons why you should test for SIBO. There may be ongoing digestive issues following the use of antibiotics and symptoms may be exacerbated after using prebiotics and probiotics. Constipation may be triggered by a high fibre diet and coeliac patients may not improve even when following a gluten free diet. Chronic digestive symptoms can start following opioid medications due to their ability to reduce gut motility. Additionally, ongoing digestive symptoms that do not improve despite therapeutic interventions.

Which medications should be avoided prior to a SIBO breath test?

Antibiotics, antifungals and probiotics should be avoided for 2 weeks prior to the test. Proton pump inhibitors, laxatives, stool softeners, bulking agents and any over the counter medications or supplements that contain fibre or promote bowel movements should be avoided 1 week prior to the test. Finally, 1 day prior to the test please stop all vitamins, minerals and supplements including digestive aids. Please note: do not stop taking any prescribed medications without consulting your medical practitioner.

What is the SIBO breath test preparation diet?

The typical preparation diet is limited to white bread, white rice, fish/poultry/meat, eggs, clear beef or chicken broth, oil, salt and pepper and the patient should fast for 8-12 hours before the test. For full instructions please refer to the full instructions included in the kit.

How long should I follow the SIBO breath test preparation diet?

A minimum of 24 hours. If you are constipated your practitioner may suggest 48 hours.

Why is the SIBO breath test preparation diet so important?

The purpose of the prep diet is to get a clear reaction to the test solution by reducing the fermentable foods the day before. In some cases, such as patients with constipation, two days of prep diet may be needed to reduce baseline gases to negative.

Can I use gluten free bread during the SIBO breath test prep diet?

Gluten free white bread must be avoided as it is very high in sugar.

Can I take the SIBO breath test if I am vegan?

Lactulose is used in one of our tests. It is derived from dairy, so it is not suitable for vegans. An alternative option would be to use glucose instead.

What happens if a SIBO test is carried out incorrectly and the test results are invalid?

If the SIBO test collection process has failed and the results are invalid, we are unable to offer a refund. If the test is still required, it must be reordered and paid for in full. This is because the laboratory does not have the ability to offer pre-analysis checks and therefore the full test analysis will be carried out on all of the samples.

Glucose or lactulose?

Glucose was the original substrate researched in this area and a lot of studies use this, but it is absorbed in the proximal small intestine. Lactulose is not absorbed and can therefore help with assessment of the small intestine to the terminal ileum. For this reason, lactulose is often the preferred choice.

What are the blood draw requirements for Cyrex?

These tests require a standard blood draw. Allow the sample to rest for 20 minutes then centrifuge for 15 minutes at 3,000 RPM. Decant the serum into the supplied white topped aliquot tube and return to the laboratory. If you are unable to centrifuge at the time of the blood draw, please return the sample in the gold topped serum tube within 24 hours of the blood draw and we will centrifuge and process accordingly.

Are there paediatric ranges for Cyrex tests? 

Paediatric ranges are not available. Be aware that antibody levels do not represent adult levels until a child is approximately 10 years old.  To conduct these tests on a child younger than this, potentiates an increased risk of false negatives. 

I have been successfully avoiding a food for many years. How long do I need to reintroduce a food before doing a Cyrex test?

The correct reintroduction of any avoided food (such as gluten or dairy) is a 7-day challenge (minimum of one small portion of challenged food/s per day for 7 days in a row).  After 7 days the challenge can cease.  Draw blood 25-30 days from the 7th day. This is to prevent false negatives after successful exclusion of that food.

Can Cyrex tests be used for patients taking steroid or immunosuppressive medications?

As a general rule, no. These medications are designed to suppress the immune system and therefore the antibody response will be suppressed. Always check the mechanism of any prescribed medication to check how it works and whether antibody levels are likely to be compromised.

How soon after finishing steroids can a patient do Cyrex testing?

60 days is best (minimum 30 days). It takes this period of time for the medication to clear the system and allow the normalized production of antibodies, required for immune testing, to resume.
You could consider running TOTAL IgA/G antibody levels FIRST, if in doubt, after use of immune suppressants / modulators / steroids.

Which order do the bloods have to be drawn for BCA Laboratory tests relating to viral, Lyme and co-infections?

The blood samples can be drawn in any order.

How do I use the barcodes supplied for BCA Laboratory tests relating to viral, Lyme and co-infections?

Use one barcode for the order form and the remaining ones on each of your samples.

Is the Vitamin D Panel (NUT10) suitable for children?

The Vitamin D panel (NUT10) is suitable for all ages however please note there are no specific paediatric reference ranges.

Why do I need to freeze my urine sample for an Organic Acids Test?

It is important to freeze your urine sample to preserve its integrity in transit. It is also important to send the frozen gel pack. Your urine must be frozen for at least 6 hours prior to sending.

How long after completing a course of antibiotics can I take an Organic Acids Test?

It is best to wait at least two weeks after taking antibiotics before taking this test.

Can I take proton pump inhibitors, for example Omeprazole, before taking an Organic Acids Test?

Proton pump inhibitors will not affect the results of this test.

If I make a mistake, for example with equipment or timing, while carrying out a DUTCH or SIBO test what should I do?

If you contact us we can replace your kit with a restock fee of £35.00