A diagnostic system comprising: a device comprising a plasma separation membrane configured to separate a plasma fraction from a first blood sample by flow of the plasma fraction through the plasma separation membrane, wherein the plasma fraction comprises plasma and an amount of hemoglobin upon the occurrence of hemolysis in the first sample; a detection system configured for receipt of the device thereon or therein and for determining the amount of hemoglobin in the plasma fraction, and, wherein the device comprises: a body with an upper portion and a lower portion; an opening defined in the body for introduction of the first blood sample; the plasma separation membrane positioned at the upper surface of the plasma separation device so as to receive the blood sample, characterized in that the diagnostic system further comprises a diagnostic instrument in communication with the detection system configured for analyzing a second blood sample from the same sample source for one or more analytes; and the device further comprises: a slit in the lower portion of the body that defines a pathway for energy to be applied to a second membrane for the detection of hemolysis; wherein the second membrane is positioned below the plasma separation membrane so as to receive the plasma fraction from the plasma separation membrane; the second membrane comprises a filter paper having a thickness sufficient to absorb and/or maintain a sample thereon without adding any discoloration to the sample; and the detection system comprises a detector for receiving and measuring energy transmitted from the membrane or energy absorbed by the membrane. a device comprising a plasma separation membrane configured to separate a plasma fraction from a first blood sample by flow of the plasma fraction through the plasma separation membrane, wherein the plasma fraction comprises plasma and an amount of hemoglobin upon the occurrence of hemolysis in the first sample; a detection system configured for receipt of the device thereon or therein and for determining the amount of hemoglobin in the plasma fraction, and, wherein the device comprises: a body with an upper portion and a lower portion; an opening defined in the body for introduction of the first blood sample; the plasma separation membrane positioned at the upper surface of the plasma separation device so as to receive the blood sample, characterized in that the diagnostic system further comprises a diagnostic instrument in communication with the detection system configured for analyzing a second blood sample from the same sample source for one or more analytes; and the device further comprises: a slit in the lower portion of the body that defines a pathway for energy to be applied to a second membrane for the detection of hemolysis; wherein the second membrane is positioned below the plasma separation membrane so as to receive the plasma fraction from the plasma separation membrane; the second membrane comprises a filter paper having a thickness sufficient to absorb and/or maintain a sample thereon without adding any discoloration to the sample; and the detection system comprises a detector for receiving and measuring energy transmitted from the membrane or energy absorbed by the membrane. a body with an upper portion and a lower portion; an opening defined in the body for introduction of the first blood sample; the plasma separation membrane positioned at the upper surface of the plasma separation device so as to receive the blood sample, characterized in that the diagnostic system further comprises a diagnostic instrument in communication with the detection system configured for analyzing a second blood sample from the same sample source for one or more analytes; and the device further comprises: a slit in the lower portion of the body that defines a pathway for energy to be applied to a second membrane for the detection of hemolysis; wherein the second membrane is positioned below the plasma separation membrane so as to receive the plasma fraction from the plasma separation membrane; the second membrane comprises a filter paper having a thickness sufficient to absorb and/or maintain a sample thereon without adding any discoloration to the sample; and the detection system comprises a detector for receiving and measuring energy transmitted from the membrane or energy absorbed by the membrane. a slit in the lower portion of the body that defines a pathway for energy to be applied to a second membrane for the detection of hemolysis; wherein the second membrane is positioned below the plasma separation membrane so as to receive the plasma fraction from the plasma separation membrane; the second membrane comprises a filter paper having a thickness sufficient to absorb and/or maintain a sample thereon without adding any discoloration to the sample; and the detection system comprises a detector for receiving and measuring energy transmitted from the membrane or energy absorbed by the membrane.