1. Evaluating the differences in the efficacy and safety of meropenem optimal dosing regimen predicted by the PPK/PD model combined with MAPB method for patients with malignant hematological myelopathy accompanied by fever, as compared with the current conventional treatment regimen;
2. The visualization software of meropenem individualized medication was developed with the help of JAVA development language, J2EE framework and SQL Server database.

Inclusion Criteria:

1. Age ≥18 years old, regardless of gender;
2. Patients with malignant hematological diseases with neutropenia and fever are judged as high-risk patients according to the Guidelines for Clinical Application of Antibiotics in Patients with Neutropenia and Fever in China (2020 Edition);
3. There is infection, and the results of drug sensitivity test show that pathogenic bacteria are sensitive to meropenem or meropenem is used according to experience;
4. The blood concentration of meropenem has reached a steady state;
5. Each patient's blood sample points ≥2, and cases with only one blood sample point can also be included in the database;
6. Sign the informed consent form.

Exclusion Criteria:

1. Patients with non-malignant hematological diseases;
2. Non-granular deficiency with fever;
3. Those who did not reach steady state when receiving meropenem;
4. There is a history of meropenem drug allergy;
5. The patient lacks treatment compliance based on the patient's history and the judgment of the researcher;
6. The patient has hemophagocytic syndrome;
7. Patients undergoing renal replacement therapy;
8. Patients with incomplete clinical evaluation data (such as lack of information on renal function and biochemical indicators, and inability to obtain blood samples);
9. The sample contains components that interfere with the determination of drug concentration (such as valproic acid and chloramphenicol);
10. Pregnant and lactating women;
11. Cases considered by the researcher as unsuitable for inclusion.