Predictivity of coagulation markers in diagnosing acute promyelocytic leukemia.

Abstract

e18544 Background: Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia (AML) characterized by life-threatening coagulopathies and bleeding. Rapid diagnosis is critical for prompt initiation of all-trans retinoic acid as confirmatory testing can take days to result. Further evaluation using readily available laboratory tests can aid early rule out of APL in patients presenting with acute leukemia. Methods: A single-center retrospective chart review of adult patients diagnosed with APL and non-APL acute myeloid leukemia (NP-AML) was conducted. All patients diagnosed with APL, confirmed by t(15;17) via FISH or PML-RARα by PCR from 2001 to October of 2025 at Stony Brook University Hospital were included in the analysis, while a similar number of NP-AML were also included. Baseline demographic and laboratory parameters including age, sex, complete blood count (CBC), creatinine, INR, PTT, fibrinogen, and D-dimer were collected and compared using the Mann–Whitney U test for continuous variables or Fischer’s exact tests for categorical variables. Sensitivity and specificity were calculated. Results: 42 patients with APL and 41 patients with NP-AML between 2001 to the present were included in the analysis. Compared with NP-AML, APL patients had significantly lower median platelet counts (16 ×10⁹/L [IQR 11-41] vs 61 ×10⁹/L [IQR 35-128], p<0.00001), white blood cells (3.27 vs 11.46 ×10⁹/L, p=0.007), ANC (0.585 vs 1.17 ×10⁹/L, p=0.044), aPTT (27.45 vs 29.1 seconds, p=0.008), and fibrinogen levels (242 mg/dL [IQR 161-343] vs 552 mg/dL [IQR 449-700], p<0.000027). Median d-dimer was significantly higher in the APL group (5922 ng/mL [IQR 2957-11694] vs 792 ng/mL [IQR 375-2231], p<0.00001). There was no significant difference in gender, hemoglobin, creatinine, INR or PT levels. D-dimer levels > 500 ng/mL were seen in all evaluable APL cases (40/40), corresponding to a sensitivity of 100%. Platelet count <150 ×10⁹/L was present in 41 of 42 APL patients (sensitivity 97.6%). Fibrinogen >250 mg/dL was observed in 40 out of 41 NP-AML patients (specificity 97.6%). Conclusions: When confirmatory diagnosis for subtypes of acute myeloid leukemia is pending, our study showed that D-dimer <500 mg/dL or platelet count >150 ×10⁹/L is highly sensitive in ruling out APL at presentation. Fibrinogen levels <250 mg/dL is also highly specific in excluding NP-AML.