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Bone Marrow Examination- Bone Marrow Aspiration

Bone Marrow Examination- Bone Marrow Aspiration 

Bone marrow examination is a procedure performed to the study of diseases of the blood. 

Bone marrow examination may be the next step after abnormal clinical findings (such as abnormal complete blood count (CBC) and/or abnormal peripheral blood smear). 

It can also be performed after an abnormal bone image (such as finding a lesion on an X-ray). 

Bone marrow examination includes: 

1. Bone marrow aspiration 

2. Clot section 

3. Bone marrow Trephine biopsy 

4. Biopsy imprint smears 

Bone marrow aspiration: 

Bone marrow aspiration is a procedure conducted by the doctor, in which a special needle is inserted into the bone marrow cavity to get bone marrow tissue specimen by suction. 

Indications for bone marrow aspiration

• Red cell disorders 

• Leucocytic disorders 

• Megakaryocyte and platelet disorders 

• Myeloproliferative disorders and myelodysplastic  syndrome with bone marrow biopsy 

• Paraproteinemias 

• Infection and Fever Unknown Origin (FUO) 

• Storage disorders 

• Iron assessment 

• Metastasis 

• Post-treatment follow up 

• Marrow harvesting for stem cell transplantation. 

Possible complications: 

● Infection 

● Bleeding 

● Broken needle 

Risk factors for complications: 

● Bleeding disorders 

● Infection of the skin overlying the area from which the specimen is to be taken 

● Infection in the bloodstream 

● Severe osteoporosis 

Bone marrow aspiration Needles: 

The needle should be solid, made of hard stainless steel about 7-8 cm long, with a well-fitting stilette, and they must be provided with an adjustable guard. 

- Most common reusable needles: Klima and Salah 

- Tips and beveled edges must maintain good sharpness 

- Islam's bone marrow aspiration needle: 

The dome-shaped handle and T-bar are designed to provide stability and control during operation 


Materials required: 

1. Sterile dressing packs. 

2. Face mask 

3. Fenestrated towel 

4. Bone marrow aspiration needle 

5. 2% lignocaine. 

6. 70% alcohol or Povidone-iodine 

7. Normal Saline solution. 

8. Sterile gloves. 

9. Sample containers: EDTA container.
10. Clean glass slides 

11. Cleaned dressing trolley 

12. Medication tray with prepared pre-medication drugs. 

13. Elastoplast
14. Syringes (5 ml & 10 ml) 

15. Pencils pen 


Obtaining Patient Medical Information and Patient assessment 

1. Perform a thorough patient history & physical examination to assess the patient for signs of malignancy, infections, lesions associated with hemorrhagic injury, as well as disorders of hemostasis and coagulation. 

2. Laboratory tests should initially include complete blood cell (CBC) counts, a reticulocyte count, peripheral blood smears, prothrombin time/international normalized ratio (PT/INR), and activated partial thromboplastin time (aPTT). All medical information reported in a bone marrow patient history form. 

3. It is very useful to know relevant laboratory data (such as iron research, folic acid or vitamin B-12 research studies, transfusion therapy, hematinic, or history of chemotherapy). 

4. The physician’s clinical impression should be included on the form. 

5. Explain the procedure in a simple language, using concrete terms, and avoiding abstract terminology. 

6. Consent- written consent should be taken from the patient. 

Before the procedure:- 

1. Assess Patient: 

• Level of consciousness or restless 

• Ability to assume the position required for the procedure. 

• Skin of procedure site 

• Vital sign 

• Lignocaine sensitivity test should be done. 

2. Notify for lab Technician and nurse on call 

3. Wash hands and wear sterile gloves.
4. Prepare about 6-8 clean glass slides and peripheral blood on the trolley and should be labeled using a pencil to write on the frosted end of the slide. Labeling requirements with the patient’s number as in booking note and a bone marrow patient history form by pencil marker.

5. Aspirate 3-5 mL of 2% lignocaine into a 5 mL syringe. 

6. Choose the appropriate needles according to the site of aspiration and the age of the patient. The aspirate needle should be checked to ensure the stylet can be easily removed from the outer needle. 

7. Prepare a 10ml syringe, assuring plungers move freely. Remove the top from one syringe and set aside. 

The nurse assist : 

• The doctor throughout the procedure 

• Pour solution 

• Give assistant to doctor when necessary 

• Observe the patient’s condition for the difficulty in breathing or unbearable pain throughout the procedure. 

• Maintain patient in a supine position and check the patient’s vital signs hourly for 4 hours. 

• Make patient comfort. 

• Put up both cot side and place call bell within the patient’s reach. 

• Cleat trolley and wash hands. 


Choose the site for aspiration 
a. Posterior superior iliac spine (preferred).
b. Anterior iliac crest.
c. Sternum at second intercostals space (higher risk).
d. Anterior medial tibia (children underage 1years). 


• Ask the patient to lie on their prone or side (left or right). 

• Palpate the iliac crest and mark the better sampling site. Locate the exact point for aspiration and outline area between thumb and index finger. 

• Disinfect the area with the disinfectant. (large area of skin at the site of the procedure and allow to dry. 

• Infiltrate the skin, subcutaneous tissue, and periosteum 

overlaying the selected site with local anesthesia. Wait 2-3 minutes for l anesthesia to take effect 

• Needle inserted in the skin then the subcutaneous tissue then cortex of the bone, which is sensed by a decreased resistance to the forward movement of the needle. 

• After entering the bone marrow cavity, the stylet will be removed. 

Using a 10 mL syringe, approximately 0.5 mL of bone marrow is aspirated. A volume greater than 0.5 mL may dilute the sample with peripheral blood and thus is not recommended. The material collected for bone marrow slides is usually not mixed with anticoagulants and should be processed immediately.

• Take out the bone marrow needle and apply pressure to the suction site with the gauze until the bleeding stops.

• Quickly put small drops on each slide and spread it gently to get good smears. 

• If there is to be a delay in slide preparation, place the sample in an EDTA containing tube & mix.

• Apply sterile dry 2×2 gauze folded into quarters and secured with tightly stretched Elastoplasts. 



• Patient supine for a while after the procedure and Remove pressure dressing after 6-12 hours. 

• Observe that the pressure dressing is tight, clean, and shows no signs of bleeding to prevent infection.

• If bleeding from the wound persists, place the patient in a supine position and cover the wound with gauze so that pressure can be applied continuously for at least 30-60 minutes.

• The patient is to be discharged with orders that the wound dressing is to be maintained in a dry state for 12 hours. The wound site should be checked frequently, and if bleeding continues or the pain increases, these findings should be reported to the clinician’s office.

• Dispose of all needles and sharps into a dedicated sharps bin and the remaining dressings, drapes, and soft materials into a yellow bin for incineration. 

• Wash B.M needles which are used gently by tap water and normal saline solution and put each needle in a separate container in a hot air oven for sterilization. The standard settings for a hot air oven are: 1 hour at 160 °C (320 °F) or 15 minutes at 190 °C (374 °F) 

Slide Preparation

1. Place a drop of collected specimen 1 cm away from the edge of the frosted "labeled" end, and then, with a second glass slide placed at a 30º angle, pull the sample to the other side with a fast and smooth stroke. Excess sample can be sucked by a needle. 

2. Bone marrow slides should be thoroughly dried before they are stained or fixed.

3. Up to three films with at least one fragment preferably more should be used for staining. The remainders of the slides are fixed in fresh methanol & filled the unstained inaccessible place, for further special stains.

4. Send the chosen slides to routine hematology lab for staining by a hematology technologist.

5. Bone marrow films should be stained with a Romanowsky stain, such as Leishman's or May-Grünwald-Giemsa. If an urgent examination is needed only one film should be fixed and stained because drying may be inadequate. The remainders of the slides are processed when thoroughly dry.

Assessing and reporting bone marrow films 

1. The films should first be examined under low power (×4 or×10 objectives) to assess the number of fragments, the cellularity, and the number of megakaryocytes, and also to detect any low incidence abnormal cells such as carcinoma cells.

2. The films should then be examined in detail using a ×40 objective.

3. There should be a systematic assessment of the cellularity and contents of fragments, megakaryocytes number, and morphology and cytological features of other lineages.

4. Fine cytological details should be assessed using an oil immersion ×100 objective.

5. Do differential count in the trails behind many fragments because this part of the film is minimally diluted by peripheral blood. At least several hundreds of cells should be counted, granulocytes and erythroid cell series, lymphocytes, and plasma cells should be enumerated, and the ratio of bone marrow to erythroid cells should be calculated.

6. If the patient has previously undergone bone marrow aspiration, it should be compared with previous films to assess disease progression or treatment response. 

7. The report of the bone marrow films should include the patient full name, age, ward, referral doctor, lab number, and date.

8. The report of the bone marrow films should include the clinical details, the major features of the blood count, the results of blood film examination, and the bone marrow findings. It is useful to include the white cell count, hemoglobin concentration, platelet count, mean cell volume, and reticulocyte count as a routine.

9. The report should then include details of the aspiration procedure, specifically the site of aspiration.

10. The report must include an assessment of cellularity and systematic description of each lineage. should be given the ratio of myeloid to erythroid cell and the salient features of the differential count.

11. The report should include a list of relevant investigations that have been performed.

12. Finally, the report should have a summary or conclusion in which it is appropriate to express an opinion and, if necessary, suggest further tests. If it is possible to make a final diagnosis this should be done. 

13. If a bone marrow aspirate fails or yields only peripheral blood it should nevertheless be reported so that a record of the attempt exists in the laboratory and the patient records. The area of aspiration and bone texture of the attempted suction should be reported.

14. The report should be signed by a hematopathologist or hematologist.

15. Print out two copies of the report one for the patient the other with Stained bone marrow slides should be filled with the unstained inaccessible place. A blood film should every time stored with the bone marrow slides.

Special Concerns

1. Pediatric cases, some cases of sternal bone marrow sampling, and those with high anxiety require general anesthesia.

2. Due to the delicate bone structure, sternal bone marrow aspiration has a higher risk of complications than other parts. Penetration of the underlying mediastinal organs can lead to mediastinitis, pulmonary embolism, pneumothorax, cardiac tamponade, and cardiac tissue damage. For these reasons, biopsies are not to be performed from the sternum. Should be done by an expert person.

3. Thrombocytopenia is not a contraindication to bone marrow aspiration and biopsy. Pressure should be applied to the site until the oozing of blood stopped.

4. Corrective action is required for coagulation disorders before bone marrow sampling.

5. Application of sterile techniques is required in the prevention of infections.

6. Dry tap, or the lack of specimen obtainment during the aspiration sampling process, is most commonly due to technical problems such as misalignment of the needle. Other conditions that should be considered and may help determine whether to perform a biopsy include recent radiotherapy, aplastic anemia, myelofibrosis, or bone infiltrating tumors. 

BM aspirate clot (BMC) 

After successfully preparing the bone marrow puncture smear in the laboratory, put the remaining bone marrow puncture particles or clots into the fixative, embedded in paraffin, and sectioned, and stained with hematoxylin and eosin (H&E). 

When the aspirate is insufficient, a section of the aspirate clot can be performed, especially if a trephine biopsy is not performed. 

These do not need decalcification and can be used to assess marrow cellularity, megakaryocyte morphology, for detecting granuloma and tumors infiltrates and can also be used for immunohistochemistry or FISH. 

Disadvantages of Marrow Aspiration 

The arrangement of cells in the bone marrow and the relationship between one cell and another is more or less disrupted by the aspiration process. 

In fibrotic marrows, little blood is also aspirated. 

Dry tap i.e. when there is little, or no marrow aspirated.