Hemoglobin levels are most often determined using an automated cell counter. A blood sample, typically collected in a tube containing EDTA anticoagulant, is analyzed. The machine converts all hemoglobin types into cyanomethemoglobin, a colored protein, then measures the color intensity using a colorimeter to determine the hemoglobin concentration.
The Process Explained:
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Blood Sample Collection: A blood sample is drawn, usually from a vein in the arm. The sample is collected in a tube containing EDTA (ethylenediaminetetraacetic acid) to prevent clotting.
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Automated Cell Counting: The blood sample is analyzed by an automated hematology analyzer. This machine is calibrated to measure several blood components, including hemoglobin.
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Cyanomethemoglobin Conversion: Within the analyzer, all forms of hemoglobin are converted to cyanomethemoglobin. This ensures consistent and accurate measurement, regardless of the various types of hemoglobin present in the blood.
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Colorimetric Measurement: The concentration of cyanomethemoglobin is determined using a colorimetric method. The intensity of the color is directly proportional to the amount of hemoglobin present. The analyzer then calculates the hemoglobin concentration (typically expressed in g/dL or g/L).
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Results Reporting: The calculated hemoglobin concentration is reported as part of the complete blood count (CBC) results.
Other Relevant Calculations:
While the hemoglobin concentration itself is directly measured, it's used in the calculation of other important red blood cell indices:
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Mean Corpuscular Hemoglobin Concentration (MCHC): This is calculated by dividing the hemoglobin concentration (in g/L) by the red blood cell (RBC) count. MCHC indicates the average concentration of hemoglobin within individual red blood cells. (Source: Sciencedirect)
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Red Cell Indices: Red blood cell indices, including MCHC, can be calculated if the hemoglobin, hematocrit (packed cell volume), and RBC count are known. (Source: NCBI Bookshelf)
It's important to remember that the specific method for hemoglobin measurement may vary slightly between laboratories, but the underlying principle remains the same: accurate and precise quantification of hemoglobin in a blood sample using automated instrumentation.
