Although diabetes has been controlled since insulin became available, it is still considered incurable and poses serious threats to human health. Reports have suggested that the hyperglycemic condition of patients with diabetes mellitus may be greatly alleviated or even reversed if it could be controlled at an early stage of diabetes. Thus, early detection and diagnosis of diabetes and prediabetes are become increasingly important in the treatment and prevention of diabetes. Diabetes mellitus is currently diagnosed by recurrent or persistent hyperglycemia. In an effort to identify novel biomarkers for diabetes, research has shown that neither plasma glucose nor glycated hemoglobin (HbA1c) levels are unable to be used in the early detection of diabetes. In this work, the investigators have found 8 biomarker candidates by developing a standard-free, label-free MS-based proteomics method based on standard protein (human serum albumin, the highest abundance protein in human plasma) model in vitro. Then, the investigators wanted to verify these biomarker candidates by clinical plasma samples to see if there is significant quantitative difference between normal people and diabetes patients.

The procedure of clinical study was:

1. to get plasma samples from hospital;
2. digestion of plasma protein-mixture by trypsin;
3. run mass spectrometry and monitor the amount of target HSA-peptides.

Inclusion Criteria:

• Type 2 Diabetes Mellitus cases;
• Impaired Glucose Tolerance cases;
• Normal Glucose Tolerance cases

Exclusion Criteria:

• Type 1 Diabetes Mellitus cases;
• Gestational Diabetes Mellitus cases;
• Hepatitis patients

university hospital, plasma samples of physical examination, faculties and staff of a certain university