Lyophilized human hemoglobin standard for colorimetric determination of total hemoglobin

Claim 2

A stable reagent suitable for conversion in solution to a cyanmethemoglobin standard for use in a colorimetric method of determining total hemoglobin in a sample of human blood by converting the hemoglobin in solution to cyanmethemoglobin and comparing the resultant color with the cyanmethemoglobin standard, said reagent comprising a vacuum-sealed container containing a known quantity of dry, stable lyophilized methemoglobin derived from human blood.

Claim 5

The method of claim 2 wherein said acid solution comprises hemolyzed blood.

Claim 6

The method of claim 2 wherein said lyophilized methemoglobin is prepared as a standard, said method including, between said filtering step and said freeze-drying step, a step of putting aliquots of filtrate into sealable vials.

Claim 7

In a method of colorimetrically determining total hemoglobin in a sample solution wherein the hemoglobin is converted in solution to a methemoglobin derivative and the color of the resultant solution is compared with the color produced by a standard solution of the same methemoglobin derivative, the improvement wherein said standard solution is prepared from a known quantity of lyophilized methemoglobin.

Claim 8

In a method of colorimetrically determining total hemoglobin in a sample solution wherein the hemoglobin is converted in solution to a methemoglobin derivative and the color of the resultant solution is compared with the color produced by a standard solution of the same methemoglobin derivative, the improvement wherein said standard solution is prepared from a known quantity of lyophilized methemoglobin.

Claim 9

The improvement of claim 5 wherein said methemoglobin derivative is cyanmethemoglobin.

Claim 10

The improvement of claim 6 wherein the conversion of hemoglobin in said sample solution to cyanmethemoglobin is accomplished by addition of a solution prepared from a dry mixture comprising about five parts potassium cyanide, 20 parts potassium ferricyanide, and salt to maintain alkalinity of the reconstituted mixture.

Claim 11

The improvement of claim 6 wherein the conversion of hemoglobin in said sample solution to cyanmethemoglobin is accomplished by addition of a Drabkin's solution and a sufficient amount of a surfactant to inhibit turbidity caused by abnormal plasma proteins, by lipids and by erythrocyte stromata.

Claim 12

The improvement of claim 8 wherein said Drabkin's solution is prepared from a known quantity of a dry mixture comprising about five parts potassium cyanide, 20 parts potassium ferricyanide, and a salt to maintain alkalinity of the reconstituted mixture.

Claim 13

The improvement of claim 9 wherein the surfactant is an aqueous solution of a polyoxyethylene ether of a fatty alcohol.

Claim 14

In a method of colorimetrically determining total hemoglobin in a sample solution wherein the hemoglobin is converted in solution to cyanmethemoglobin and the color of the resultant solution is compared with a standard, the improvement wherein conversion of the hemoglobin in the sample to cyanmethemoglobin is accomplished by a reagent prepared from a non-ionic surface active agent and from a dry mixiture comprising about five parts potassium cyanide, twenty parts potassium ferricyanide, and about one hundred parts of a salt to maintain a high ionic strength in the reconstituted reagent, said reconstituted reagent having a pH between about 8 and about 9; and wherein said standard is a solution prepared from: a known quantity of a dry, stable hemoglobin derivative; a non-ionic surface active agent; and a dry mixture comprising about five parts potassium cyanide, 20 parts ferricyanide, and about 100 parts of a salt to maintain a high ionic strength in the reconstituted standard, said reconstituted standard having a pH between about 8 and about 9.

Claim 15

In a method of colorimetrically determining total hemoglobin in a sample solution wherein the hemoglobin is converted in solution to cyanmethemoglobin and the color of the resultant solution is compared with a standard, the improvement wherein conversion of the hemoglobin in the sample to cyanmethemoglobin is accomplished by a reagent prepared from a non-ionic surface active agent and from a dry mixiture comprising about five parts potassium cyanide, twenty parts potassium ferricyanide, and about one hundred parts of a salt to maintain a high ionic strength in the reconstituted reagent, said reconstituted reagent having a pH between about 8 and about 9; and wherein said standard is a solution prepared from: a known quantity of a dry, stable hemoglobin derivative; a non-ionic surface active agent; and a dry mixture comprising about five parts potassium cyanide, 20 parts ferricyanide, and about 100 parts of a salt to maintain a high ionic strength in the reconstituted standard, said reconstituted standard having a pH between about 8 and about 9.