False-positive results using the solubility test may be obtained in persons with increased red blood cell counts as occur in polycythemias; extremely high white counts, as in some leukemias; and extremely high platelet counts. Increased levels of lipids or globulins may also cause a false-positive.
Hemoglobins that show a positive solubility test include HbC-Harlem, HbC-Georgetown, and HbC-Ziquinchor.
False-negatives in the solubility test may be obtained on persons with severely decreased hemoglobins/hematocrits and those recently transfused. Infants less than six months old may also demonstrate false-negative results due to higher levels of HbF.
False results in the solubility test can occur due to problems with technique: too much or too little blood added will result in false-positive and false-negative respectively; use of incorrect size test tube, holding the test tube too close to the background, and using deteriorated reagents can all lead to false-negative results.
