With the diversity of sideroblastic anemia causes, the diagnosis will rely on the combination of laboratory findings, clinical symptoms, and family history. Some commonalities will be present.
The presence of Pappenheimer bodies, combined with a dimorphic red blood cell population consisting of microcytic/hypochromic cells and normochromic cells will be an early indicator of a sideroblastic process. As we saw, the results of iron studies, displayed in Table 9, will help support further investigation. In addition, evaluation of FEPs and ZPPs can provide additional insight. Free erythrocyte protoporphyrins or FEPs are those intermediate byproducts left from incomplete heme formation. In the absence of iron, zinc has an affinity for the formed protoporphyrin ring forming zinc erythrocyte protoporphyrins (ZPPs).
Table 9. Iron Study Results Found in Sideroblastic Anemia.| Iron Studies | Results |
| Serum Iron | Increased |
| Serum Ferritin | Increased |
| TIBC | Decreased |
| Transferrin saturation | Increased |
| FEP/ZPP | Increased |
| sTfR | Normal |
Bone marrow examination for the presence of ring sideroblasts confirming the presence of more than 15% ring sideroblasts triggering next steps.
The flow chart below provides initial guidelines for categorizing possible causes.28
28. Modified from Patnaik, MM and Tefferi, A. "Refractory anemia with ring sideroblasts (RARS) and RARS with thrombocytosis (RARS-T): 2017 update on diagnosis, risk-stratification, and management." Am J Hematol. 2017; 92: 297; 310. https://doi.org/10.1002/ajh.24637.
