Hematology

Diagnosis: The Search for a Cause

At a Glance

Primary acquired PRCA is diagnosed when red-cell production is severely reduced, the bone marrow has few or no red-cell precursors, and tests do not identify a secondary cause such as thymoma, parvovirus B19, T-LGL leukemia, MDS, or medication effects.

The diagnosis of primary Pure Red Cell Aplasia (PRCA) is a process of elimination. Because the “primary” label means your doctors cannot find an external cause, they must first perform a rigorous, individualized search for “secondary” triggers. This involves detailed blood work, a specialized look at your bone marrow, and reviewing your medications ^[1]^[2].

The Blood and Marrow Signature

The first clue to PRCA is a specific pattern in your blood and marrow. In your blood, doctors look for reticulocytopenia—a severe reduction of reticulocytes (the “baby” red blood cells that the marrow normally pumps out every day) ^[3].

The Threshold: A diagnosis of PRCA often involves an absolute reticulocyte count (ARC) of less than 10,000/µL (or $10 \times 10^9/L$ ) ^[3]^[4].
The Marrow Finding: In a bone marrow biopsy, a pathologist will look for erythroblastopenia. This means that while your marrow looks healthy and “full” (cellular) overall, the specific cells that become red blood cells (erythroblasts) are severely reduced or missing entirely ^[4]^[5].
Preservation: Critically, the cell lines for your white blood cells (granulocytes) and platelets (megakaryocytes) typically appear preserved ^[6]^[7].

Evaluating Secondary Causes

Before your PRCA is called “primary,” your medical team will typically evaluate you for several “secondary” categories. Each is assessed based on your clinical picture:

1. Thymoma (Thymus Gland Tumor)

Some adults with PRCA have a thymoma, a tumor in the thymus gland located in the chest ^[8]. Even if the tumor is benign (non-cancerous) and removed, the PRCA may persist and still require immunosuppression, so care is coordinated between hematology and thoracic specialists.

Often Considered: A Chest CT scan to look at the area behind your breastbone (the mediastinum) ^[9]^[8].

2. Parvovirus B19

This common virus can suppress red cell production in adults ^[10]. Under a microscope, it sometimes leaves a clue in the marrow: giant proerythroblasts (unusually large, early red cells), though these are not always present ^[11]^[12].

Often Considered: A PCR blood test for Parvovirus B19 DNA. This is often interpreted alongside standard antibody tests (IgM/IgG) depending on your immune status ^[13]^[14].

3. T-LGL Leukemia

T-cell Large Granular Lymphocytic (T-LGL) leukemia is a slow-growing chronic condition that can affect the marrow ^[15]. It is sometimes associated with PRCA.

Often Considered: Flow cytometry and T-cell receptor (TCR) gene rearrangement testing. Finding a T-cell clone does not automatically mean you have T-LGL leukemia, so specialist interpretation is required ^[15]^[16].

4. Myelodysplastic Syndrome (MDS)

MDS is a group of disorders where the bone marrow does not produce enough healthy blood cells. Sometimes early MDS can look like PRCA ^[17].

Often Considered: Cytogenetics (karyotyping) to look at the structure of your chromosomes and Next-Generation Sequencing (NGS) to check for specific gene mutations ^[2]^[18].

Diagnostic Completeness

If you are being told your PRCA is “primary” or “idiopathic,” ensure your doctors have thoroughly reviewed your history. If any tests are missing, it is worth asking your hematologist if they are necessary for your case.

Category	Often Considered	What it Evaluates
Imaging	Chest CT Scan	Thymoma (Thymus tumor)
Virology	Parvovirus B19 PCR	Active viral suppression
Pathology	Bone Marrow Biopsy	MDS or other disorders
Immunology	Flow Cytometry	T-LGL Leukemia
Genetics	Cytogenetics / NGS	MDS or Clonal disorders
Blood Work	Absolute Reticulocyte Count	Confirms red cell failure

If these evaluations are negative for an underlying disease, your diagnosis is considered Primary Acquired PRCA ^[1]^[2]. However, your doctors will continue to monitor you, as a secondary cause can sometimes emerge later on.

Common questions in this guide

How is primary acquired PRCA diagnosed?

Doctors look for a severe reduction in reticulocytes, the young red blood cells released by bone marrow, and often an absolute reticulocyte count below 10,000/µL. A bone marrow biopsy should show very few or no red-cell precursors while other blood-cell lines are generally preserved. The diagnosis is called primary only after secondary causes have been investigated.

What should a bone marrow biopsy show in PRCA?

The marrow is often normally cellular overall, but erythroblasts—the cells that develop into red blood cells—are severely reduced or absent. White blood cell and platelet-producing cells are typically preserved. The pathologist also checks for findings that could point to infections, myelodysplastic syndrome, or another marrow disorder.

Why is a chest CT part of the PRCA workup?

A chest CT can look for a thymoma, a tumor of the thymus gland in the chest. Thymoma can be associated with PRCA, and PRCA may continue even after the tumor is removed, so hematology and thoracic specialists may coordinate care.

How is parvovirus B19 checked when PRCA is suspected?

Doctors may order a blood PCR test that looks for parvovirus B19 DNA, along with IgM and IgG antibody tests when appropriate. A bone marrow sample may show unusually large early red-cell precursors called giant proerythroblasts, but their absence does not rule out the infection.

What tests look for T-LGL leukemia or MDS in someone with PRCA?

Flow cytometry and T-cell receptor gene rearrangement testing can look for an abnormal T-cell population associated with T-LGL leukemia. A T-cell clone alone does not prove that diagnosis. Cytogenetic testing and next-generation sequencing may help identify MDS or other clonal marrow disorders.

Can medicines cause red-cell aplasia?

Some medicines may suppress red blood cell production, so a careful review of prescription drugs, over-the-counter products, and supplements is part of the evaluation. Do not stop a medicine on your own; ask your hematologist whether any exposure could be relevant and whether an alternative is needed.

Curated prompts to bring to your next appointment.

1.What was my absolute reticulocyte count, and is it below the 10,000/µL threshold common for PRCA?
2.Does the pathology report describe my bone marrow as 'normally cellular' aside from the missing red cell precursors?
3.Were 'giant proerythroblasts' or viral inclusions found in my marrow that might suggest Parvovirus B19?
4.Have we performed a chest CT to rule out a thymoma, even if I don't have any chest symptoms?
5.Did my flow cytometry or T-cell receptor testing show any evidence of T-cell Large Granular Lymphocytic (T-LGL) leukemia?
6.Are specialized tests like Next-Generation Sequencing (NGS) indicated in my case?

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References (18)

1
Pure red cell aplasia.
Means RT
Hematology. American Society of Hematology. Education Program 2016; (2016(1)):51-56 doi:10.1182/asheducation-2016.1.51.
PMID: 27913462
2
Clinical heterogeneity and outcome of acquired PRCA: a multicenter European study.
Versino F, Michel M, Vidler J, et al.
Blood advances 2026; (10(15)):5285-5292 doi:10.1182/bloodadvances.2025019525.
PMID: 42200581
3
A nomogram model for predicting the efficacy of cyclosporine in patients with pure red cell aplasia.
Yang L, Niu H, Zhang T, et al.
Annals of hematology 2024; (103(6)):1877-1885 doi:10.1007/s00277-024-05636-9.
PMID: 38308019
4
Refractory anemia in human immunodeficiency virus: Expect the unexpected.
Mirgh SP, Mishra VA, Shah VD, Sorabjee JS
Journal of family medicine and primary care 2016; (5(3)):727-729 doi:10.4103/2249-4863.197288.
PMID: 28217621
5
Hepatitis C Infection Associated with Acquired Pure Red Cell Aplasia.
Teague D, Gurnari C, Awada H, et al.
Tropical medicine and infectious disease 2022; (8(1)) doi:10.3390/tropicalmed8010008.
PMID: 36668915
6
Spectrum of Pure Red Cell Aplasia in a Tertiary Care Hospital in Northeast India.
Dey B, Raphael V, Shangpliang DM, et al.
Cureus 2025; (17(2)):e79364 doi:10.7759/cureus.79364.
PMID: 40125126
7
ESA-induced pure red cell aplasia presenting as a precipitous hemoglobin drop in end-stage renal disease.
Mui JSK
Archive of clinical cases 2026; (13(2)):38-42 doi:10.22551/2026.51.1302.10339.
PMID: 42553667
8
Pure Red Cell Aplasia That Developed 13 Years After Thymoma Treatment: A Case Report and Literature Review.
Kono K, Nakashima K, Tsubata Y, et al.
Thoracic cancer 2025; (16(17)):e70157 doi:10.1111/1759-7714.70157.
PMID: 40879193
9
[Pure white cell aplasia combined with thymoma and lung cancer: a case report and literature review].
Chen XL, Cai ZJ, Zheng R, Lin WQ
Zhonghua xue ye xue za zhi = Zhonghua xueyexue zazhi 2024; (45(8)):789-793 doi:10.3760/cma.j.cn121090-20240113-00018.
PMID: 39307729
10
Pure red cell aplasia: The second hundred years.
Means RT
The American journal of the medical sciences 2023; (366(3)):160-166 doi:10.1016/j.amjms.2023.06.009.
PMID: 37327996
11
Parvovirus B19.
Landry ML
Microbiology spectrum 2016; (4(3)) doi:10.1128/microbiolspec.DMIH2-0008-2015.
PMID: 27337440
12
Rheumatoid arthritis flare mimicry by parvovirus B19.
Patil P, War GA, Sahoo DP, et al.
Modern rheumatology case reports 2026; (10(1)) doi:10.1093/mrcr/rxag031.
PMID: 42113608
13
Parvovirus B19-triggered Acute Hemolytic Anemia and Thrombocytopenia in a Child with Evans Syndrome.
Zikidou P, Grapsa A, Bezirgiannidou Z, et al.
Mediterranean journal of hematology and infectious diseases 2018; (10(1)):e2018018 doi:10.4084/MJHID.2018.018.
PMID: 29531655
14
Case Report: Pure Red Cell Aplasia Caused by Refractory Parvovirus B19 Infection After Pancreas Transplantation Alone.
Lindahl JP, Barlinn R, Abrahamsen IW, et al.
Frontiers in medicine 2022; (9()):849783 doi:10.3389/fmed.2022.849783.
PMID: 35372384
15
Treatment for CD57-negative γδ T-cell large granular lymphocytic leukemia with pure red cell aplasia: A case report.
Xiao PP, Chen XY, Dong ZG, et al.
World journal of clinical cases 2021; (9(26)):7818-7824 doi:10.12998/wjcc.v9.i26.7818.
PMID: 34621832
16
A case report of T-LGL leukemia-associated pure red cell aplasia harboring STAT3, TNFAIP3, and KMT2D mutation.
Shen M
Translational cancer research 2023; (12(4)):1054-1059 doi:10.21037/tcr-23-326.
PMID: 37180665
17
Clinicopathological associations of acquired erythroblastopenia.
Gunes G, Malkan UY, Yasar HA, et al.
International journal of clinical and experimental medicine 2015; (8(12)):22515-9.
PMID: 26885236
18
Somatic Mutations and Mutation Burden Predict Treatment Response and Survival in Adult Acquired Pure Red Cell Aplasia.
Yang L, Zhang H, Wei Y, et al.
American journal of hematology 2026; (101(7)):1443-1450 doi:10.1002/ajh.70311.
PMID: 41922159

This page describes the diagnostic workup for primary acquired PRCA for informational purposes only and does not constitute medical advice. Your hematologist and pathologist should interpret your results and decide which tests are appropriate for your situation.

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