[Comparison of hemolytic characteristics among paroxysmal nocturnal hemoglobinuria, autoimmune hemolytic anemia and hereditary spherocytosis].

Objective: To determine the valuable hemolytic characteristics in differential diagnosis of paroxysmal nocturnal hemoglobinuria (PNH), autoimmune hemolytic anemia (AIHA) and hereditary spherocytosis (HS). Method: The clinical and hemolytic characteristics of 108 PNH patients, 127 AIHA patients and 172 HS patients diagnosed from January 1998 to April 2017 were compared. Results: ①Reticulocyte percentage (Ret%) of PNH patients [6.70% (0.14%-22.82%)] was significantly lower than that of AIHA [14.00%(0.10%-55.95%), P <0.001] and HS patients [11.83%(0.60%-57.39%), P <0.001]. The Ret% in PNH patients were significantly lower than those in AIHA and HS patients at the same levels of anemia, except for in mild anemia between PNH and AIHA patients. However, when comparing the Ret% between AIHA and HS patients, there was significant difference only in mild anemia [7.63%(1.87%-29.20%)% vs 11.20%(3.31%-22.44%), z =-2.165, P =0.030]. ②The level of TBIL in HS patients was significantly higher than that in AIHA and PNH patients [79.3 (11.2-244.0) μmol/L vs 57.6 (7.6-265.0) μmol/L, z =5.469, P <0.001; 79.3(11.2-244.0) μmol/L vs 26.2(4.6-217.7) μmol/L, z =-2.165, P <0.001], and the proportion of HS patients with TBIL more than 4 times the upper limit of normal (ULN) (64.1%) was significantly higher than that of AIHA (37.7%, χ (2)=19.896, P <0.001) and PNH patients (4.6%, P <0.001). ③The LDH level of PNH patients was significantly higher than that of AIHA and HS [1 500 (216-5 144) U/L vs 487 (29-3 516) U/L, z =-9.556, P <0.001; 1 500 (216-5 144) U/L vs 252 (132-663) U/L, z =-11.518, P <0.001], and the proportion of PNH patients with LDH more than 1 000 U/L (79.1%) was significantly higher than that of AIHA patients (13.0%, χ (2)=93.748, P <0.001) and HS patients (0, P <0.001). ④Splenomegaly occurred in 43.5% of PNH patients, including 16.0% with severe splenomegaly. In contrast, the occurrence of splenomegaly was 98.6% in AIHA patients and 100.0% in HS patients ( P <0.001), and 63.0% of AIHA patients ( P <0.001) and 90.4% of HS patients ( P <0.001) were with severe splenomegaly. ⑤The prevalence of cholelithiasis in HS patients was up to 43.1%, significantly higher than that in AIHA patients (10.5%, P <0.001) and PNH patients (2.9%, P <0.001). Conclusion: The comprehensive assessment of the five hemolytic characteristics is simplified, practical and efficient, with great clinical significance, providing specific indicators for differential diagnosis and efficient approach for making further work-up.