Reticulocyte hemoglobin equivalent (Ret-He)

How much haemoglobin sits in your newest red blood cells, which shows whether iron is reaching them right now.

Last reviewedAugust 17, 2026

Whole blood

sample type

~3 mL

blood needed

~10 days

results in app

Any time of day

best timing

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On this page

Why test Reference ranges What you'll learn What affects it How testing works Sources FAQ

In short

Every new red blood cell needs iron to build haemoglobin, the protein that carries oxygen. Ret-He measures the average amount of haemoglobin inside your reticulocytes, the cells that have just left the bone marrow.

Because those cells are only a day or two old, the value reflects how much iron was available for production this week rather than months ago.

Blood Health (CBC & Iron)

Reviewed against DGKL reference practice.

Why test this?

Ferritin tells you about iron in storage. Ret-He tells you whether iron is actually reaching the cells being built today. The two can disagree, and when they do, Ret-He is often the more useful of the pair.

That matters most when inflammation is in play. Inflammation pushes ferritin up and can hide a real iron shortage, while Ret-He stays low because the marrow still cannot get the iron it needs. It also responds within days of starting iron, long before ferritin or haemoglobin move.

What is a normal result?

Aniva reads your result against research-backed ranges, not just the lab's wide normal. The reference shown below is specific to this biomarker.

Adult reference values as used by Aniva. Ret-He is analyser dependent, so the interval printed by the measuring laboratory takes precedence.

Group	Typical adult range
Adults	28 to 36 pg

Values below roughly 28 pg are commonly read as a sign that iron is not reaching new red blood cells. Your Aniva report reads your result against the reporting laboratory's interval together with your ferritin, transferrin saturation and the rest of your panel.

Ranges are guidance and vary by lab and assay, aligned with DGKL practice. Always read your result against your own lab's reference interval.

What insights will this test give you?

Whether iron is reaching your newest red blood cells right now.
A read on iron status that inflammation does not distort the way it distorts ferritin.
Early confirmation, often within a week, that iron supplementation is working.

What can affect this result?

What can skew the result

The value is analyser dependent and different manufacturers report it under different names, so compare results from the same laboratory. Thalassaemia trait and other haemoglobin variants lower Ret-He without iron being short, and recent transfusion shifts the reading.

Best interpreted with

Read together with ferritin, iron, transferrin saturation, haemoglobin and MCH, and next to the reticulocyte count.

How is this tested?

Sample

Whole blood

Blood needed

~3 mL

Method

Flow cytometry

Best timing

Any time of day

Sources. The evidence behind this

MedlinePlus: Reticulocyte Count

MedlinePlus: RBC Indices

Common questions

What does Ret-He tell me that ferritin does not? Ferritin shows iron in storage. Ret-He shows whether iron is reaching the red blood cells being built now, which is why it stays useful when inflammation lifts ferritin.

Do I need to fast for this test? No. Eat and drink normally.

What can affect my result? Thalassaemia trait and other haemoglobin variants lower it without iron being short. Recent transfusion and the analyser used also matter.

How quickly does it respond to iron? Often within about a week, well before ferritin or haemoglobin catch up.

How long do results take? Results are usually ready in about 10 days.

What should I discuss with my clinician? Ask how Ret-He sits next to your ferritin and transferrin saturation, especially if you have inflammation or a chronic condition.

Which Aniva panels include this marker?

Core

Your annual full-body baseline with more than 100 biomarkers, included in your Aniva membership.