Isotretinoin blood tests and first appointment: what patients can expect
If you are considering oral isotretinoin for severe or scarring acne, it is reasonable to wonder what happens before the first capsule is prescribed. The process is more than a blood test: it includes confirming that isotretinoin is an appropriate option, reviewing previous treatment, discussing risks, and arranging ongoing monitoring.
Blood tests commonly include liver function and fasting blood lipids. A pregnancy test is also required for patients who could become pregnant, but it may be a urine test rather than a blood test. Your exact plan depends on your medical history, results and the service’s protocol. [1–4]
Why are blood tests needed?
Isotretinoin can affect liver enzymes and the level of fats, particularly triglycerides, in the blood. Most patients do not develop a serious problem, but testing helps the prescriber identify an abnormal result before treatment and detect changes afterwards.
Current UK product information recommends checking liver enzymes and fasting lipids before treatment, again one month after starting, and then at three-month intervals unless more frequent monitoring is clinically indicated. [2] Some dermatology services use a slightly different timetable based on the dose, results, patient risk factors and local protocol.
More frequent checks may be appropriate if you have diabetes, obesity, high cholesterol or triglycerides, a lipid disorder, or significant alcohol intake. The clinician may also request blood glucose monitoring in some higher-risk patients. [2]
What happens at the first isotretinoin appointment?
Under current MHRA guidance, the initial assessment before isotretinoin is started should be in person. Later reviews may be remote when clinically appropriate. The lead prescriber must have expertise in systemic retinoids and understand the treatment’s risks and monitoring requirements. [3,4]
The first appointment should usually cover:
the pattern, severity and duration of your acne;
scarring or risk of permanent scarring;
topical treatments and oral antibiotics already tried;
current medicines, supplements and allergies;
relevant medical history, including liver or lipid problems;
pregnancy potential and contraception where relevant;
the effect of acne on daily life and wellbeing; and
possible benefits, limitations, side effects and alternatives.
NICE recommends isotretinoin for people aged over 12 with severe acne that is resistant to adequate courses of standard therapy, including systemic antibiotics and topical treatment. It is not automatically the next step for everyone with persistent spots. [5]
Which blood tests are usually arranged?
Liver function tests
These measure enzymes that can rise if the liver is irritated. Tell the clinician about liver disease, other medicines and how much alcohol you drink. The NHS advises avoiding alcohol while taking isotretinoin because of the potential for liver problems. [1]
Lipid profile
This usually includes triglycerides and cholesterol. The product information specifies fasting lipid values, so follow the clinic or laboratory instructions about food and drink before the sample. Do not assume you need to fast unless you have been told to do so.
Other tests when indicated
Extra tests are not identical for every patient. They may be added because of symptoms, medical history, medication interactions or an unexpected result. A blood count is sometimes requested by local protocols, but it is not a substitute for liver and lipid monitoring.
Is pregnancy testing part of the blood tests?
Pregnancy testing is a separate safety requirement and does not necessarily require blood to be taken. All patients of child-bearing potential must be enrolled in the Pregnancy Prevention Programme. The programme allows some flexibility according to individual pregnancy risk, but a patient cannot simply be “opted out” of the programme. [4]
Testing may be performed at home under medical supervision if appropriate instructions are provided, the test has the required sensitivity and the prescriber verifies the result. The timing and frequency depend on the patient’s circumstances and current programme requirements. [4]
Isotretinoin must not be used during pregnancy. Effective contraception is required for patients who could become pregnant, beginning before treatment and continuing during treatment and for at least one month afterwards, according to the agreed plan. Tell the service immediately if pregnancy occurs or is suspected. [1,2]
What if a result is abnormal?
An abnormal result does not always mean treatment is impossible, and a single result should not be interpreted without its context. The prescriber may repeat the test, look for another cause, delay starting, alter the dose or recommend a different treatment.
Product information advises considering dose reduction or stopping treatment if clinically relevant liver enzyme elevations persist. Uncontrolled high triglycerides may also require treatment to be stopped. [2] Do not change the dose yourself or use somebody else’s capsules.
Monitoring is not only about blood
The MHRA requires assessment of mental health before treatment and monitoring during follow-up. Patients should also be asked about sexual function concerns before treatment and monitored for new problems. [3,4]
These questions are not intended to exclude everyone with a previous mental health problem. They help the clinician understand your baseline, discuss uncertainty and put appropriate support in place. Be honest about low mood, anxiety, self-harm, sexual symptoms and relevant family history.
You should also receive age-appropriate written information, an Acknowledgement of Risk form, and advice to watch the BAD/MHRA patient information video before treatment. [3]
How can I prepare?
Bring or send an accurate list of:
acne treatments and how long you used them;
prescribed medicines, vitamins and supplements;
allergies and medical conditions;
any previous blood results you have been asked to provide;
contraception details, if relevant; and
questions about monitoring, costs and follow-up.
Mention vitamin A supplements and tetracycline antibiotics such as doxycycline, because they can interact with isotretinoin. [1] Ask who arranges the blood tests, who reviews the result, whether fasting is needed and how quickly you will be contacted if there is a problem.
When should I seek urgent help?
While taking isotretinoin, contact your treatment team promptly about concerning side effects. The NHS advises urgent help for possible serious reactions, including severe abdominal pain with nausea or vomiting, breathing difficulty, seizures, hallucinations, psychosis, or thoughts of suicide or self-harm. Call 999 for symptoms of a severe allergic reaction such as tongue or throat swelling with difficulty breathing. [1]
Frequently asked questions
Can I start isotretinoin before the results are back?
Treatment should not start until the prescriber has completed the required assessment and reviewed the necessary baseline results.
Will I need a blood test every month?
Not necessarily. Product information gives a baseline, one-month and then three-month schedule unless closer monitoring is needed, but your clinician’s plan may differ for valid clinical reasons. Pregnancy testing follows separate requirements. [2,4]
Does a normal blood test mean isotretinoin is suitable?
No. Results are only one part of the decision. Acne severity, previous treatment, pregnancy safety, mental and sexual health assessment, interactions and your preferences all matter.
Taking the next step with mySkinDoc
mySkinDoc describes a structured, doctor-led isotretinoin pathway for suitable patients, including assessment, counselling, blood-test monitoring and follow-up. You can review the current acne and isotretinoin pathway and book an assessment through the options shown there. Booking an assessment does not guarantee that isotretinoin will be prescribed.
References
Sources checked on 1 October 2026.
