Haematology Watch

Haematology Watch, Vol 3, Issue 1.


Sudan Black B (SBB) stain

 Abbas Hashim Abdulsalam* and Nafila Sabeeh

Al-Yarmouk Teaching Hospital, Teaching Laboratories Department, Hematology Unit


In under-resourced laboratories, the diagnosis of acute leukemia is essentially based on clinical presentation and the basic hematological investigations including complete blood count and blood smear morphology, after which a bone marrow aspirate and sometimes a trephine biopsy will follow (1).

Locally available special techniques are very limited apart from few immunohistochemistry CD markers and PCR or FISH testing for BCR-ABL oncogene only. Therefore, it is essential to optimally use the peripheral blood and bone marrow smears Romanowsky and special stain morphology, including SBB, which remain the backbone for acute leukemia diagnosis (2).

      The appealing characters that entitle the use of SBB stain are:

1.   The reaction and non-reaction with SBB stain are both practically significant, as the former refers characteristcally to AML and the latter is highly supportive of the diagnosis of ALL. With the proper clinical settings, SBB stain negativity is more sensitive than lineage specific stains like PAS positive reaction.   

2.   The intensity of a positive reaction with SBB in general parallels myeloperoxidase activity. However, SBB is preferable as it is slightly more sensitive than myeloperoxidase staining in the detection of myeloblasts (3).

3.   Better demonstration of Auer rods by using SBB stain than any of the usual Romanowsky stains. This would be of utmost benefit to identify all MDS cases with Auer rods, differentiate AML-M1 from ALL-L2 cases and to follow up AML cases for morphological remission after induction chemotherapy, since in all AML subtypes, except for AML-M3 (4), the presence of even one blast cell with Auer rod would refer to failure to achieve remission and indicate the need for a second induction chemotherapy course.

4.   The presence of at least 3% SBB stain positive blasts would characteristically refer to the diagnosis of AML-M1 rather than ALL, although it is now about 30 years since first reporting that in very rare cases even ALL blasts may show SBB positivity (5).

5.   Increased SBB stain positivity at diagnosis is associated with better prognosis (6). 

6.   Speedy and firm enough diagnosis of AML-M3 variant cases to start ATRA treatment in the same day (7).

7.   Demonstration of myeloid series dysplasia (8).

8.   The stain can be easily applied to peripheral blood (7) as well as bone marrow aspirate smears.

How to count the percentage of SBB positively stained blasts:

The literatures are always referring to directly counting the blasts from the SBB stain slide (9), which is the best technique if the blasts can be easily recognized, but in practice and especially with AML-M1 this is not always feasible due to the nature of the stain which renders many blasts indistinguishable from other less immature cells. Therefore, there should be a second best technique to count the percent of smear positive SBB blasts, because it is not always possible to differentiate all the blasts directly from the SBB slide.

In the authors’ laboratory the following procedure is applied by first utilizing the Leishman stain slide for counting cells into 3 categories as fractions from all the total marrow cells:

1st the blast cells. 2nd the maturing myeloid cells, which would be all assumed to stain positive, although some may actually be negative as a feature of myelodysplasia but nevertheless in calculations this would provide a higher safety threshold to avoid inappropriately classifying a case as AML. 3rd category for lymphocytes and nucleated red cells, which would be negatively stained.

Then from the SBB stain slide count all the SBB positive cells and deduce the relative percentage of the SBB positive blasts.

* Corresponding author: Dr. Abbas Hashim Abdulsalam,; Mobile 009647904188690; E-Mail: dr.abbas77@yahoo.com


1. Abbas HA. Chemotherapeutic trial for acute leukemia in Iraq. Turkish Journal of Hematology, 2009; 26 (4): 216.

2. Abbas HA. Laboratory diagnosis of acute leukemia in Iraq, the available options. Turkish Journal of Hematology, 2010; [In press].

3. Bain BJ. Blood cell, a practical guide. 4th ed. 2006; Blackwell publishing.

4. Wong KF. All-trans-retinoic acid therapy. British Journal of Haematology. 2010; 149: 309.

5. Tricota G, Broeckaert-Van Orshoven A, Van Hoof A, Verwilgdhen RL. Sudan Black B positivity in acute lymphoblastic leukaemia. British Journal of Haematology, 1982; 51: 615-621.

6. Hoyle CF, Gray RG, Wheatly K, Swirsky D, De Bastos M, Sherrington P, Rees JKH, Hayhoe FGJ. Prognostic importance of Sudan Black B positivity: a study of bone marrow slides from 1386 patients with de novo acute myeloid leukaemia. British Journal of Haematology, 1991; 79: 398-407.

7. Abbas HA. Cytological/cytochemical diagnosis of the variant form of acute promyelocytic leukaemia. BloodMed, Slide atlas, British Society of Haematology. 2010; Wiley-Blackwell.

8. Bain BJ. Neutrophil dysplasia demonstrated on Sudan black B staining. American Journal of Hematology, 2010; 85 (9): 707.

9. Bain BJ. Leukaemia diagnosis. 4th ed. 2010; Wiley-Blackwell.