Condition Guide

Aplastic Anaemia

Name: Aplastic Anaemia: Blood Tests, Causes & Treatment
Creator: Suman Konda
Published: 2026-07-05

Aplastic anaemia is a rare but serious condition where the bone marrow stops making enough blood cells. A bone marrow biopsy alongside blood tests confirms the diagnosis.

Written by Suman Konda, PharmD, Clinical Pharmacist · Based on peer-reviewed sources · Editorial policy · Not medical advice

Last updated: 01 August 2026 · How we check our content

Blood test findings in aplastic anaemia

Test	Finding	Severity threshold
Haemoglobin	Low	<8 g/dL = severe
Neutrophils (ANC)	Very low	<500/µL = severe; <200/µL = very severe
Platelets	Very low	<20,000/µL = severe
Reticulocyte count	Very low	<1% = hypoproliferative bone marrow
Bone marrow biopsy	Hypocellular: mostly fat cells	Confirms diagnosis

What is aplastic anaemia?

Pancytopenia from bone marrow failure

In aplastic anaemia, the bone marrow's blood-forming stem cells are destroyed, usually by an autoimmune T-cell attack. The result is pancytopenia: low red blood cells (anaemia), low white blood cells (neutropenia, risk of serious infections), and low platelets (thrombocytopenia, risk of bleeding). Without treatment, severe aplastic anaemia is life-threatening. Causes include autoimmune (most common), viral infections (EBV, hepatitis), toxic exposures, radiation, and rarely inherited (Fanconi anaemia).

Treatment options

Treatment	For whom
Allogeneic bone marrow transplant	Severe aplastic anaemia in patients <40 with matched sibling donor: potential cure
Immunosuppression (ATG + cyclosporin)	Severe AA without a matched donor, or older patients
Eltrombopag (TPO receptor agonist)	Added to immunosuppression to boost marrow recovery
Supportive care	Blood and platelet transfusions, antibiotics for infections

Questions to ask your haematologist

Is my pancytopenia severe enough to need bone marrow transplant?
Has a cause been found for my aplastic anaemia?
Do I have a matched sibling donor for transplant?
What infections should I watch for with low neutrophils?

Frequently Asked Questions

What makes aplastic anaemia different from other anaemias?

In aplastic anaemia the bone marrow fails to produce enough of all blood cells, red cells, white cells, and platelets, unlike iron-deficiency anaemia, which affects red cells due to low iron.

What are the main symptoms?

Because all blood cell lines fall, symptoms include fatigue and pallor (low red cells), frequent infections (low white cells), and easy bruising or bleeding (low platelets).

How is aplastic anaemia diagnosed?

A full blood count showing low counts across all cell types (pancytopenia) prompts a bone marrow biopsy, which confirms the reduced marrow activity characteristic of the condition.

What makes aplastic anaemia different from other anaemias

Most anaemias affect red cells alone. Aplastic anaemia is a failure of the bone marrow itself, so all three cell lines fall together: red cells, white cells and platelets. That pancytopenia is the defining feature and the reason the illness presents with three separate kinds of problem at once, namely fatigue and breathlessness from anaemia, infections from neutropenia, and bruising or bleeding from thrombocytopenia. A low haemoglobin with normal white cells and platelets is not aplastic anaemia and points elsewhere.

The other distinguishing feature is the reticulocyte count. In most anaemias the marrow responds by producing more young red cells, so reticulocytes rise. In marrow failure they are inappropriately low, which is one of the earliest clues that the problem is production rather than loss or destruction.

Why a bone marrow biopsy is necessary

Blood counts can show pancytopenia but cannot show why. The marrow biopsy distinguishes an empty, hypocellular marrow, which characterises aplastic anaemia, from a marrow crowded out by leukaemia, lymphoma, myeloma or metastatic cancer, and from myelodysplastic syndrome, which can look similar on blood counts but behaves and is treated quite differently. Cytogenetic testing on the sample also identifies clonal abnormalities that change prognosis and management.

Causes and associations

Idiopathic autoimmune destruction of marrow stem cells, which accounts for most acquired cases.
Drugs: chloramphenicol historically, and carbamazepine, some NSAIDs, gold and antithyroid drugs among others.
Viral infection, particularly seronegative hepatitis, and parvovirus B19 in specific settings.
Toxins such as benzene, and radiation exposure.
Inherited marrow failure syndromes including Fanconi anaemia and dyskeratosis congenita, which need excluding in younger patients.

Living with it while treatment takes effect

Immunosuppressive therapy and stem cell transplantation both take time to work, so supportive care carries much of the load early on. Fever in someone with a very low neutrophil count is a medical emergency requiring immediate antibiotics, not a wait-and-see situation. Avoiding intramuscular injections, contact sports and aspirin or NSAIDs reduces bleeding risk while platelets are low. Attention to dental and skin care lowers infection risk. These measures are unglamorous but they are what keeps people well enough to reach definitive treatment.

References

The clinical information on this page is drawn from peer-reviewed sources indexed by the US National Library of Medicine. Links go to the source so you can read it yourself.

Aplastic Anemia. In: StatPearls. Treasure Island (FL): StatPearls Publishing. NCBI Bookshelf NBK534212