How to read the bone marrow test report?

Author: Shen Jun, Chief Technician of China-Japan Friendship Hospital

Reviewer: Zhu Dan, Chief Physician, Peking University Third Hospital

Bone marrow cell morphology test is a commonly used clinical examination method that can help diagnose hematopoietic system diseases. However, when patients receive the bone marrow test report, they are often confused and cannot understand it at all. Today we will talk about the relevant content and hope to answer your questions.

First of all, what does a bone marrow report contain? In addition to the patient's basic information and clinical diagnosis, it mainly includes two parts: one is the percentage count of cells contained in the bone marrow; the other is a text description based on the cell percentage and the overall condition of the bone marrow, which is also the most important part of a bone marrow report, mainly including the patient's bone marrow proliferation, the proportion and morphological description of each type of hematopoietic cell, whether there are abnormal cells and diagnostic opinions. Next, I will briefly introduce the above contents one by one.

1. Degree of proliferation

Normal people and patients with benign diseases show active proliferation or significantly active proliferation, while patients with blood diseases mostly show significantly active to extremely active proliferation. Those with reduced or extremely reduced proliferation are commonly seen in hypohematopoietic function, aplastic anemia, partial or complete dilution of bone marrow puncture, etc.

2. Bone marrow hematopoietic cell morphology examination

Blood cells are divided into primitive cells, immature cells and mature cells according to their developmental stages. The bone marrow is mainly composed of primitive and immature cells. After the cells of each lineage mature, they are released into the peripheral blood through the myeloid-blood barrier, so the peripheral blood is full of mature blood cells. When the number or composition of cells in the bone marrow changes, it can be manifested in the peripheral blood or clinical symptoms.

1. What could be the possible cause of an increase or decrease in granulocyte count?

Granulocytes account for the highest proportion of bone marrow nucleated cells, generally accounting for 40%-60%. When the proportion increases significantly, it is common in leukemoid reactions caused by very serious infections, chronic myeloid leukemia, etc. In addition to changes in proportion, there are also changes in cell components, such as an increase in primitive cells. When the number of primitive cells increases but is less than 20%, it is chronic leukemia, and when the proportion of primitive cells is ≥20%, it is acute leukemia. Granulocytopenia is common in granulocytopenia, agranulocytosis, aplastic anemia, or chemotherapy, which can all cause granulocytopenia.

2. What could be the possible cause of an increase or decrease in the erythroid system?

Normally, immature red blood cells account for about 20% of the bone marrow. Increased red blood cells are common in proliferative anemia, such as iron deficiency anemia, megaloblastic anemia, hemorrhagic anemia, and hemolytic anemia with relatively vigorous proliferation. People who live in plateaus for a long time will have a compensatory increase in the red blood cell count in order to supply oxygen. Decreased red blood cell count is common in patients with pure red blood cell aplastic anemia, aplastic anemia, or after chemotherapy.

3. What might be the possible cause of an increase in primitive and immature lymphocyte cell lines?

In normal bone marrow, primitive lymphocytes and immature lymphocytes are basically not found. Generally, these two types of cells can only be found in the bone marrow of patients with blood system diseases. In the bone marrow of healthy people, mature lymphocytes are found, accounting for about 20%. Increased primitive and immature lymphocytes are often seen in malignant diseases of the lymphatic system, such as acute lymphocytic leukemia.

The most common occurrence of mature lymphocyte proliferation is chronic lymphocytic leukemia. There are also some benign, reactive increases in mature lymphocytes, such as infectious mononucleosis.

In addition, in aplastic anemia, due to the decrease in hematopoietic cells, non-hematopoietic cells, especially lymphocytes, may show a relative increase.

4. What could be the possible cause of an increase or decrease in megakaryocyte cell lineage?

The name "megakaryocyte" is relatively unfamiliar. In fact, it is a cell that produces platelets. It is also divided into primitive and immature stages. Generally, in a smear of 1.5cm×3cm, 7-35 megakaryocytes are seen, and they are all mature megakaryocytes. When the number or morphology of megakaryocytes changes, it will affect the number of platelets, resulting in clinical symptoms. For example, in the common ITP, that is, immune thrombocytopenic purpura, the number of megakaryocytes is significantly increased, but the platelet-producing megakaryocytes, that is, platelet-producing megakaryocytes, are significantly reduced, which manifests as a significant decrease in platelets and clinical bleeding symptoms. Thrombocytopenia is also common in aplastic anemia. We know that in aplastic anemia, the granulocytes, red blood cells, and megakaryocytes will be significantly reduced, but the reduction of megakaryocytes is the earliest. In addition, exposure to chemicals such as xylene and benzene, or radiotherapy and chemotherapy, can also cause megakaryocyte reduction.

Figure 1 Original copyright image, no permission to reprint

5. Are there abnormal cells?

When lymphoma cells infiltrate the bone marrow of lymphoma patients, abnormal lymphoma cells can be found in the bone marrow. The presence of lymphoma cells in the bone marrow is particularly important for the diagnosis, staging and treatment of the disease. Some patients with solid tumors will have bone marrow metastasis, so non-hematopoietic cells, namely tumor cells, can be found in the bone marrow.

3. Diagnostic opinion

According to the bone marrow picture, blood picture and histochemical staining, combined with clinical data, a diagnosis or reference opinion is given; for diseases with a clear diagnosis, the bone marrow picture should be compared with the previous one, and the disease remission situation should be given, such as complete remission, partial remission or recurrence. If the sample is not good, the clinician may recommend a bone marrow puncture re-examination at a different site.