Concierge haematology · London
Haematocrit — what a high or low result really means.
The haematocrit is the proportion of your blood that is red cells. Persistently high or low is not just a number — it is a clue that leads to venesection, iron, B12 or transfusion. We work up the cause, then arrange the treatment.
Why patients choose us
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A consultant haematologist, not a portal
A raised or low haematocrit is not just a number on a printout. A named haematologist reads it in context — with the JAK2, the ferritin, and you.
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The right test before the treatment
JAK2, EPO level, iron studies, B12 and folate before anyone reaches for venesection or a transfusion. First the cause, then the therapy.
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Independent, and free
We are paid by no clinic, so the recommendation — venesection, iron, transfusion or watch-and-wait — is impartial and costs you nothing.
Indicative pricing
What a private haematocrit work-up and treatment cost in London.
Indicative ranges across our partner clinics — from the initial blood draw to a full course of venesection or iron infusion. Firm figures within one working day.
In short
A haematology consult with FBC in our network: £300–£490, plan in place the same day.
| Test or treatment | Indicative range | Typical duration | Turnaround |
|---|---|---|---|
| Full blood count (FBC / HCT) | £45–£90 | 5 min draw | Same day |
| Haematology consultation (initial) | £250–£400 | 30–45 min | Same visit |
| JAK2 V617F mutation testing | £180–£320 | 5 min draw | 5–10 days |
| Erythropoietin (EPO) level | £90–£160 | 5 min draw | 3–7 days |
| Therapeutic venesection (per session) | £180–£350 | 45–60 min | Same visit |
| IV iron infusion (Ferinject / Monofer) | £450–£850 | 30–60 min | Same visit |
| Blood transfusion (per unit, day-case) | £500–£900 | 2–4 hours | Same visit |
Prices vary by clinic, by which haematologist takes the case, and by how many venesection or infusion sessions are needed. We confirm the pathway and firm figures within one working day.
The problem
An abnormal haematocrit is not a diagnosis — it is a clue.
A high haematocrit could be dehydration, sleep apnoea, testosterone use, smoking or polycythaemia vera. A low one could be iron, B12, kidneys, marrow, or a bleed no one has found yet. The treatment only works if the cause is right.
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A high haematocrit needs a cause
JAK2, EPO level, sleep review, testosterone status. Venesection alone is not an answer.
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A low haematocrit needs a search
Iron studies, B12, folate, coeliac screen, endoscopy if indicated. Iron tablets for an unexplained anaemia over 50 is a missed cancer.
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The right treatment, at the right dose
Venesection, hydroxycarbamide, IV iron, B12 injections, EPO or transfusion — chosen for your cause, not off a template.
The journey
From an abnormal FBC to a settled haematocrit — in order.
One haematologist from first message to long-term follow-up — including the day-case treatment sessions in between.
Phase 1 · Before treatment
Work-up and pathway design
Phase 2 · On the day
Consultation and first session
Phase 3 · After
Recheck and long-term plan
- 01
Before
You send us the result
The FBC printout, or a photo of it. Symptoms, medications, and whether the haematocrit came back high or low.
- 02
Before
We come back with a plan
Within one working day: which follow-on tests you need (JAK2, EPO, ferritin, B12), which specialist to see, and what the treatment pathway looks like.
- 03
Before
We arrange the consultation
A consultant haematologist, usually within one to two weeks. Bloods drawn on the day if not done already.
- 04
On the day
The consultation itself
30 to 45 minutes with the haematologist. Full history, examination, review of every previous FBC, and a written plan you leave with.
- 05
On the day
First treatment session, if needed
A venesection (for polycythaemia) or an iron infusion (for anaemia) can often be arranged the same day at the day-case unit.
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After
Repeat FBC and dose adjustment
A recheck in two to six weeks. Venesection frequency, iron dose or transfusion trigger is tuned to your response.
- 07
After
Long-term monitoring
For polycythaemia vera, quarterly FBCs and a lifelong plan. For anaemia, follow-up until the cause is treated and the count restored.
Typical end-to-end to first treatment: 1–2 weeks from enquiry. Long-term follow-up: 3–6 monthly for PV.
Causes
Why a haematocrit rises or falls.
The commonest causes we see — and the one red flag that means A&E rather than an appointment.
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Polycythaemia vera (PV)
A JAK2-driven bone-marrow disorder — the commonest primary cause of a persistently raised haematocrit.
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Smoking and lung disease
COPD, obstructive sleep apnoea and heavy smoking all push the haematocrit up as the body compensates for low oxygen.
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Testosterone or anabolic steroids
TRT and anabolic use raise the haematocrit reliably — one of the commonest causes we see in men aged 40–70.
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Dehydration (apparent polycythaemia)
A falsely high haematocrit from low plasma volume — often diuretics, alcohol or simple under-drinking. Repeat hydrated.
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Iron-deficiency anaemia
Heavy periods, coeliac disease or occult GI blood loss are the usual culprits — the haematocrit falls with the haemoglobin.
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B12 or folate deficiency
A macrocytic, low-haematocrit picture — dietary, malabsorption, or pernicious anaemia. Simple to treat once identified.
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Chronic kidney disease
The failing kidney makes less erythropoietin, so the haematocrit drops. EPO-stimulating agents restore it.
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Red flag: HCT above 55%
A haematocrit above 55%, or a very low HCT with breathlessness or chest pain, is not for the waiting list — same-day medical review.
Treatment options
The therapies that move the haematocrit.
What each option actually involves — from a venesection session to an IV iron infusion, hydroxycarbamide or a blood transfusion.
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Therapeutic venesection
A carefully measured phlebotomy — 450–500ml removed every 1–3 weeks initially — to bring the haematocrit safely below 45%, the BSH target for PV.
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Aspirin 75mg daily
Low-dose aspirin reduces clot risk in polycythaemia vera. Standard alongside venesection unless there is a bleeding contraindication.
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Hydroxycarbamide (hydroxyurea)
First-line cytoreduction for high-risk PV — a daily tablet that quietens the bone marrow and reduces the need for venesection over time.
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Interferon alfa (peg or ropeg)
Peginterferon alfa-2a, or ropeginterferon (Besremi, NICE TA669) — preferred for younger patients and pregnancy planning. A weekly or fortnightly injection.
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Ruxolitinib (Jakavi)
A JAK1/2 inhibitor for PV that has not responded to hydroxycarbamide (NICE TA738) — a daily tablet, tightly monitored.
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Iron replacement
Oral ferrous sulphate 200mg on alternate days (better absorbed) for straightforward iron deficiency; IV iron (Ferinject or Monofer) when oral is not tolerated, absorbed, or fast enough.
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B12 and folate replacement
B12 by intramuscular injection every three months (or high-dose oral for maintenance); folate as a 5mg oral tablet. Corrects the count over weeks.
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Blood transfusion
Reserved for symptomatic anaemia — the BSH restrictive trigger is Hb under 70 g/L (80 g/L with cardiac disease). Not a first-line treatment.
Our vetted London network
A small panel of haematologists, we picked them.
Consultant haematologists across central, north, west and south London — with attached day-case units for venesection, iron and transfusion.
Selection criteria
How we choose every haematologist in our network.
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Consultant haematologists, not trainees or general physicians
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Access to JAK2, EPO and full myeloproliferative work-up on site
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Day-case venesection and IV iron on the same clinic visit where possible
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Underlying cause investigated before any lifelong therapy is started
Safety and monitoring
What to expect from treatment — honestly.
Venesection, iron and B12 are safe, well-established treatments. Cytoreductive drugs and transfusion are worth their trade-offs when the count and the cause justify them.
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Venesection is well tolerated
Removing 450ml — the same volume as a blood donation — is safe for most adults. Some feel light-headed briefly; the team monitors you throughout.
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Iron infusions carry a small risk
IV iron is efficient but rare hypersensitivity can happen — always given in a monitored setting with resuscitation to hand, per MHRA guidance.
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Aspirin is not for everyone
Low-dose aspirin is standard in PV but not if you have active bleeding, ulcers or specific allergies. The haematologist checks before starting.
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Hydroxycarbamide needs monitoring
A safe drug when watched — regular FBCs check the marrow response and pick up any dip in white cells or platelets early.
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PV is a long-term condition
Polycythaemia vera is not curable but is very controllable. Life expectancy is close to normal when the haematocrit is kept under 45%.
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Transformation is uncommon but real
A minority of PV patients transform to myelofibrosis or acute leukaemia over decades — the reason for lifelong follow-up.
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Transfusion is a temporary fix
A transfusion buys time; it does not treat the cause. Iron deficiency, B12 loss or a GI bleed still needs investigating.
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Investigate before you treat
Iron for an unexplained anaemia in an adult over 50 without an endoscopy is a missed cancer waiting to happen. NICE is clear on this.
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Red flags
A haematocrit above 55%, sudden severe headache, visual changes, chest pain or new breathlessness are reasons to attend A&E, not to wait.
Reading your haematology report
Your report in four parts. Read the last one first.
Whether the haematocrit is high or low, the haematologist’s letter keeps to the same shape.
A quiet reminder
Haematology language is precise and can read coldly — we translate it for you.
If you would like us to talk you through the report before your next appointment, just ask.
- 01 Header
The numbers, and how they compare
Your haematocrit, haemoglobin, red-cell count and mean cell volume — with the reference range and your previous FBCs alongside.
- 02 Findings
What the picture points to
Whether the pattern is micro-, normo- or macrocytic; whether the platelets and white cells fit a myeloproliferative picture; any features on the blood film.
- 03 Technique
Follow-on tests requested
JAK2 mutation, EPO level, ferritin, B12, folate, TFTs, renal and liver function — the panel that separates primary from secondary and iron from B12.
- 04 Impression
Plan and treatment recommendation
Read this first: the likely cause, the recommended treatment (venesection, iron, B12, transfusion or watch-and-wait), and when to recheck.
Recognised by major UK insurers
Cover for haematology consultation, venesection and infusion varies by insurer and by indication — usually funded when medically indicated. We confirm cover before booking.
Frequently asked
Everything we get asked about the haematocrit.
Quick answers on reference ranges, high and low results, venesection, iron and when to worry.
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What is a haematocrit, in plain English?
It is the proportion of your blood that is made up of red cells — usually expressed as a percentage. A normal haematocrit is roughly 40–50% for men and 36–46% for women. It is reported as part of a full blood count and is sometimes called the packed cell volume (PCV).
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My haematocrit is high — should I worry?
One raised reading is often dehydration or a lab quirk. A persistently high haematocrit needs investigating — usually with a JAK2 mutation test, an erythropoietin level and a look for causes like sleep apnoea, lung disease, testosterone use or, less commonly, polycythaemia vera.
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What is the treatment for a high haematocrit?
Once the cause is known, the mainstay is therapeutic venesection — removing 450–500ml of blood every one to three weeks until the haematocrit is under 45%. Aspirin is added for polycythaemia vera, and cytoreductive drugs like hydroxycarbamide, interferon or ruxolitinib are considered for higher-risk patients.
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What is the treatment for a low haematocrit?
It depends on the cause. Iron replacement (oral or intravenous) treats iron-deficiency anaemia; vitamin B12 injections treat B12 deficiency; folate tablets treat folate deficiency; an EPO-stimulating agent is used for chronic kidney disease; and blood transfusion is reserved for symptomatic anaemia below Hb 70 g/L (or 80 g/L with heart disease), per BSH guidance.
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Is polycythaemia vera cancer?
It is a myeloproliferative neoplasm — a slow-growing blood cancer of the bone marrow driven, in more than 95% of cases, by a JAK2 V617F mutation. Life expectancy with good control is close to normal, but it does need lifelong follow-up.
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How often will I need a venesection?
At first, every one to three weeks until your haematocrit is under 45%. Once controlled, most patients need a venesection every six to twelve weeks. The exact interval is set by your response.
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Does testosterone replacement affect my haematocrit?
Yes. TRT reliably raises the haematocrit and is one of the commonest reversible causes we see in men. Guidance is to check the FBC before starting, at three and six months, then yearly — and to pause or reduce the dose if the haematocrit climbs above 54%.
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When should I go to A&E?
A haematocrit above 55% with headache, visual changes, chest pain or breathlessness needs same-day medical attention. A very low haematocrit with chest pain, severe breathlessness or fainting also needs A&E rather than a clinic booking.
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