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- Free Hemoglobin
- Hb Solubility
- Hemoglobin, Free
- Plasma Free Hemoglobin
Evaluate hemolytic anemia, especially intravascular hemolysis. Plasma hemoglobin is increased with intravascular hemolysis, ABO incompatible transfusion, traumatic hemolysis, falciparum malaria, burns, and march hemoglobinuria. Increase may occur in some cases of extravascular hemolysis, delayed transfusion reaction, slight increase in sickle cell anemia, and β-thalassemia.
High (>20 mg/dL) bilirubin, turbidity, methemalbuminemia, lipemic plasma, and hemolysis during or after venipuncture may cause falsely elevated values in the plasma hemoglobin test (method based on peroxide oxidation of TMB).
Based on the catalytic action of hemoglobin on the oxidation of TMB by hydrogen peroxide; rate measured by spectrophotometry
<5 mg/dL (if conditions are optimal). Values obtained between 5−15 mg/dL should be interpreted with caution since such variables as suboptimal venipuncture may increase results to this range.
Recommended procedure for collecting sample without inducing hemolysis: An 18-gauge needle with attached infusion tubing is used. Place the tourniquet lightly around the upper arm. Puncture an antecubital vein with as little trauma as possible. Release the tourniquet and clamp the tubing off as soon as blood return is seen. First collect 3 mL blood in a red-top tube with the rubber top off. Then, collect 5 mL in an anticoagulated tube with the top off. Clamp the tubing, withdraw the needle, and apply a pressure bandage to the site until residual bleeding is stopped. Recap the anticoagulant tube and gently mix three to five times. This specimen is used for the plasma hemoglobin determination. Centrifuge and separate plasma from red cells immediately following collection. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.
Refrigerate at 2°C to 8°C or freeze at -20°C for up to three days.
Causes for Rejection
Traumatic venipuncture causing hemolysis; very icteric or lipemic specimen; specimen not heparinized plasma
|Order Code||Order Code Name||Order Loinc||Result Code||Result Code Name||UofM||Result LOINC|
|005595||Hemoglobin, Free, Plasma||721-1||005596||Hemoglobin, Free, Plasma||mg/dL||721-1|