The college loves Heinz bodies and Howell-Jolly bodies. RBC inclusion bodies have appeared in several SAQs, and are usually associated with a question on post-splenectomy vaccination. Most often, the question is worth 10-20% of a multi-part question, and represents easy marks for the person who can remember a handful of differentials. Thus far, the college has not ask anything about siderocytes or  basophilic stippling.

Representative SAQs include the following:

  • Question 7.2 from the first paper of 2016 (Post-splenectomy Howell-Jolly bodies)
  • Question 12.2 from the second paper of 2012 (Post-splenectomy Howell-Jolly bodies)
  • Question 24.3 from the second paper of 2010 (Heinz bodies in G6PD)
  • Question 18 from the second paper of 2007 (Post-splenectomy film)

Howell-Jolly bodies

Howell-Jolly bodies are bits of lefteover DNA in the erythrocytes. Normally, the spleen would view these as defective, and they would be removed. They are typically seen in patients who have had a splenectomy.

Other associations include the following conditions:

  • Pernicious anaemia
  • Macrocytosis of any cause
  • Corticosteroid use

Heinz bodies

Heinz bodies, also known as Heinz-Ehrlich bodies are essentially little lumps of denatured haemoglobin within the red cells. They typically indicate some sort of oxidative stress. This sort of abnormality is usually seen in disorders of red cell metabolism and haemoglobinopathies. Additonally, a normal individual probably has a few RBCs with Heinz bodies, but they are rapidly cleaned up by splenic macrophages (and thus after splenectomy they begin to accumulate).

Increased oxidative stress due to toxins

  • Primaquine
  • Toxic solvents, eg. aniline, benzene, naphthalene
  • Quinidine

Unstable haemoglobins

  • Chronic liver disease
  • Alpha-thalassaemia
  • Certain congenital "Heinz body anaemias"
  • Methylene blue methaemoglobinaemia

Deranged RBC metabolism

  • Dapsone toxicity
  • Glucose-6-phosphate dehydrogenase deficiency
  • Trimethoprim-sulfamethoxazole (Bactrim)

Decreased clearance of defective RBCs

  • Post splenectomy

Miscellaneous RBC inclusion bodies:

Blister cells: blebs on the surface of RBCs, suggestive of oxidative damage; seen with G6PD deficiency as well as in various oxidative stress states, eg. dapsone or primaquine toxicity. Within the same film one might expect a few Heinz bodies.

Pappenheimer bodies: hemosiderin-containing granules seen in sideroblastic anaemia

Basophilic stippling: altered ribosomes in the cytoplasm; seen with lead poisoning


Kyle, R. A., and S. V. Rajkumar. "Criteria for diagnosis, staging, risk stratification and response assessment of multiple myeloma." Leukemia 23.1 (2009): 3-9.


Aherne, W. A. "The differentiation of myelomatosis from other causes of bone marrow plasmacytosis." Journal of clinical pathology 11.4 (1958): 326-329.

Constantino, Benie T., and Bessie Cogionis. "Nucleated RBCs—significance in the peripheral blood film." Lab Medicine 31.4 (2000): 223-229.

SCHMIDT, JOHN J., HAROLD J. ROBINSON, and CHARLES S. PENNYPACKER. "Peripheral plasmacytosis in serum sickness." Annals of internal medicine 59.4 (1963): 542-546.

Bäumler, H., et al. "Basic phenomena of red blood cell rouleaux formation."Biorheology 36.5 (1999): 439-442.

Wagner, Christian, Patrick Steffen, and Saša Svetina. "Aggregation of red blood cells: From rouleaux to clot formation." Comptes Rendus Physique 14.6 (2013): 459-469.

REPLOGLE, ROBERT L., HERBERT J. MEISELMAN, and EDWARD W. MERRILL. "SPECIAL ARTICLE Clinical Implications of Blood Rheology Studies." Circulation 36.1 (1967): 148-160.

Ponder, Eric. "On sedimentation and rouleaux formation-I." Experimental Physiology 15.3 (1925): 235-252.

Aslinia, Florence, Joseph J. Mazza, and Steven H. Yale. "Megaloblastic anemia and other causes of macrocytosis." Clinical medicine & research 4.3 (2006): 236-241.

Walker, H. Kenneth, et al. "Peripheral blood smear." (1990). in Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition.

Bessis, Marcel. "Codocytes and Target Cells." Corpuscles. Springer Berlin Heidelberg, 1974. 59-64.

Jones, Kathy W. "Evaluation of Cell Morphology and Introduction to Platelet and White Blood Cell Morphology." I do not know which textbook this is form, but it is a chapter which is available for free online ... for now.

Bull, BRIAN S., J. Breton-Gorius, and E. Beutler. "Morphology of the erythron."New York, McGraw Hill (2001): 271-288. - this is an online re-posting of a chapter of Williams' Haematology, but without the figures.

Corazza, G. R., et al. "Howell‐Jolly body counting as a measure of splenic function. A reassessment." Clinical & Laboratory Haematology 12.3 (1990): 269-275.

Bain, Barbara J. "Diagnosis from the blood smear." New England Journal of Medicine 353.5 (2005): 498-507.

Sakka, Vissaria, et al. "An update on the etiology and diagnostic evaluation of a leukemoid reaction." European journal of internal medicine 17.6 (2006): 394-398.

ul Haque, Anwar, and Noor ul Aan. "Leukemoid Reaction: Unusual Causes." International Journal of Pathology 8.1 (2010): 39-40.

HARLEY, JOHN D., and ALVIN M. MAUER. "Studies on the formation of Heinz bodies. II. The nature and significance of Heinz bodies." Blood 17.4 (1961): 418-433.

JANDL, JAMES H. "The Heinz body hemolytic anemias." Annals of internal medicine 58.4 (1963): 702-709.