Most people notice it in the toilet bowl, think "that looks odd" and carry on with the day. Stools that are pale, grey or the colour of putty are easy to dismiss once. If they keep coming out that way, a simple blood test can tell you quickly whether the liver is involved.
Yes, once pale stools keep coming back, a liver function test (LFT) is a sensible first step, because it looks at the liver and bile ducts directly. You can book a liver function test at 117a Harley Street or simply walk in, any day of the week. It costs £72.50 plus the £50 blood draw, and the result is back in 1 day.
"If your stools keep coming out pale, have a liver function test and talk it over with a doctor. It's a simple blood test, and it tells us quickly whether the liver is involved."
Dr Mohammad Bakhtiar, Clinical Lead, GMC 4694470
Why stools turn pale
Stool gets its usual brown colour from bile, which the liver makes and sends down the bile ducts into the gut. When less bile arrives, stools lose colour. Bile flow can slow or become blocked, for example by gallstones, and liver conditions such as hepatitis or alcohol-related liver disease can have the same effect. The NHS lists paler poo alongside darker urine and itchy skin as signs of jaundice, which is what happens when bilirubin builds up in the body.
What to notice over the first few days
One pale stool after an unusual meal or a stomach upset is common, and it tends to settle.
Keep a loose eye on three things:
- Colour. Pale grey, clay or putty colour, compared with your usual brown.
- Pattern. Whether it was once, or has happened on two or more days running.
- Anything alongside it. Yellowing of the skin or the whites of the eyes, dark urine, itching, or a dull ache under the right ribs.
Together, pale stools, dark urine and yellow skin or eyes suggest bile flow is blocked, and they need same-day care: ask for an urgent GP appointment or call NHS 111. Yellow skin or eyes with a high temperature or sudden, severe tummy pain need emergency care, and NHS advice is to call 999 or go to A&E. Pale stools in a baby need an urgent appointment with a GP or midwife, or a call to NHS 111, because a rare condition called biliary atresia is one possible cause.
When the pattern is repeating
Pale stools on two or more days in a row are the point to come in. You can have the test before any other symptom appears. A blood test now gives you an answer rather than a week of wondering, and it gives a doctor something concrete to look at.
What does the test cost?
The liver function test panel is £72.50, plus the £50 blood draw (£122.50 in total). The result is back in 1 day.
The panel measures eight markers from one sample: bilirubin, ALT, AST, total protein, ALP, albumin, globulin and GGT. Buying just five of them separately would cost more. ALT, ALP, GGT, bilirubin and albumin come to £193.77 between them. The panel gives you those five plus AST, total protein and globulin, with one £50 draw per visit.
If you would like a doctor to go through the numbers with you, a Blood London doctor review can be added to the test for £75.
The visit
Blood London sees walk-ins seven days a week at 117a Harley Street, Monday to Friday 09:00 to 18:00 and Saturday and Sunday 10:00 to 14:00. Tell reception you are here for the liver function test, and a phlebotomist takes one blood sample from your arm. That single sample is measured for all eight markers, so there is nothing more to arrange. You can also book online if you prefer a set time.
Your sample reaches the lab the same day, and the report is ready the next day.
When the result arrives
Two patterns are worth knowing about, because they are what a doctor looks at first:
- ALT, AST and GGT are enzymes that move into the blood when liver cells are irritated.
- ALP and bilirubin tend to point towards the bile ducts, which carry bile on its way to the gut.
No single number settles it. What matters is how the markers sit together, which our guide to liver function test results walks through marker by marker.
A result inside range is useful too, because it moves the question to other causes, and a doctor can take it from there. A result outside range is a reason to talk it through with a doctor soon. The test is a first step, and a doctor may arrange further tests, such as an ultrasound scan, depending on what the result shows.
Seeing a doctor afterwards
Whatever the result shows, it helps to have a doctor look at it alongside your symptoms. Our sister clinic, Medical Express Clinic, offers private GP appointments at the same address, with a £150 consultation and no fixed time limit.
Questions people ask
What colour should stools be?
Shades of brown are usual, and green or yellow-brown can come from diet. Pale grey, clay or putty colours are the ones worth having checked if they last.
How long should I wait before getting a liver function test?
A single pale stool is rarely a reason to test. When it has happened on two or more days running, or comes with dark urine or itching, book without waiting any longer.
Do I need to fast before the test?
Most people do not need to fast for this panel. Tell the phlebotomist about any alcohol or regular medicines, since both can affect certain markers.
Book your test
Pale stools that keep coming back deserve an answer. Book a liver function test for £72.50 plus the £50 draw, or browse our other private blood tests in London.