Distinguishing thrombotic thrombocytopenic purpura from primary immune thrombocytopenia accompanied by anemia using the carbon monoxide breath test

Figures & data

Table 1. Characteristics of study subjects included in the study.

	Healthy subjects	ITP patients with anemia	TTP patients
Male/female	11/19	12/20	8/15
Age(years)	44.6 ± 11.93	45.5 ± 19.5	48.04 ± 12.23
Hemoglobin(g/L)	142.3 ± 9.53	104.75 ± 9.9*	81.61 ± 18.58^*#
Platelets (×10^9/L)	209.1 ± 45.4	7.59 ± 4.41*	11.7 ± 9.12*
Reticulocyte (%) (normal reference value:0.5–1.5)	1.26 ± 0.26	1.86 ± 0.4	8.84 ± 6.61^*#
LDH (U/L) (normal reference value: 120–250)	174.93 ± 30.44	188.88 ± 38.97	1215.13 ± 655.78^*#
Indirect bilirubin (umol/L) (normal reference value: 1.5–18.0)	7.50 ± 3.92	9.02 ± 5.23	31.35 ± 17.06^*#
Creatinine (umol/L)(normal reference value: 41–73)	60.47 ± 7.19	63.61 ± 11.12	83.68 ± 58.13
Triggers of TTP	–	–	13(56%)
Infection	–	–	6 (26%)
Vaccination	–	–	3 (13%)
Autoimmune disease	–	–	4 (17%)

Data are presented as mean ± SD or number (%). *p < 0.05 vs. healthy subjects. ^#p < 0.05, vs. ITP patients with anemia. ITP: primary immune thrombocytopenia, TTP: thrombotic thrombocytopenic purpura, LDH: lactic dehydrogenase.

Figure 1. Scatter plots showing RBCLS for three groups. The mean RBCLS was found to be shorter in TTP patients (n = 23) compared to ITP patients accompanied by anemia (n = 32). Furthermore, the mean RBCLS was significantly shorter in patients with ITP accompanied by anemia compared to healthy controls (n = 30). Among ITP patients, those without gastrointestinal (GI) bleeding (n = 20) exhibited higher RBCLS values than those with GI bleeding (n = 12). Mean and SD are shown for each group. The long horizontal dashed line indicates baseline normal RBCLS. RBCLS: red blood cell lifespan, HC: healthy controls, ITP: primary immune thrombocytopenia, TTP: thrombotic thrombocytopenic purpura.

Figure 2. Correlation between RBCLS and clinical laboratory indices in 23 TTP patients. A: RBCLS versus reticulocyte percentage; B: RBCLS versus lactic dehydrogenase level. RBCLS: red blood cell lifespan, TTP: thrombotic thrombocytopenic purpura.

Figure 3. ROC curve for predicting TTP using RBCLS, LDH and RET. ROC: receiver operating characteristic, TTP: thrombotic thrombocytopenic purpura, LDH: lactate dehydrogenase, RET: reticulocyte.

Data availability statement

The datasets analyzed in this study can be requested from the corresponding author upon a reasonable request.