Hemoglobin by molecules such as carbon monoxide (for example, from tobacco smoking, exhaust gas, and incomplete combustion in furnaces). CO competes with oxygen at the heme binding site. Hemoglobin's binding affinity for CO is 250 times greater than its affinity for oxygen, meaning that small amounts of CO dramatically reduce hemoglobin's ability to transport oxygen. Since carbon monoxide is a colorless, odorless and tasteless gas, and poses a potentially fatal threat, carbon monoxide detectors have become commercially available to warn of dangerous levels in residences. When hemoglobin combines with CO, it forms a very bright red compound called carboxyhemoglobin, which may
Complete blood count many cells, the results are very precise. However, certain abnormal cells in the blood may not be identified correctly, requiring manual review of the instrument's results and identification by other means (such as microscopy) of any abnormal cells the instrument could not categorize. Sophisticated modern analyzers can provide extended WBC differential counts, which include hematopoietic progenitor cells, immature granulocytes, and erythroblasts. Various Red blood cell indices (parameters calculated from other CBC results) are often reported in addition to cell counts and hemoglobin. Automated hematology analyzers calculate the average amount (MCH) and concentration (MCHC) of hemoglobin within each red blood cell.