Abstract: A nethod of verifying sample volume quantifies the fluid volume aspirated and verifies sample uniformity by detecting the presence of foam or clots in the sample. After aspiration, a pressure sensor is used to measure the vacuum needed to hold up the column of fluid in the probe tip. By knowing the geometry of the probe tip, the vacuum can be converted to a sample weight and volume, based on sample densities. Non-ideal conditions, such as foam on the surface of the fluid or a clot in the fluid, result in a sample volume much lighter in the case if foam, or much greater, in the case of a clot, than anticipated. The method also determines the elapsed time of the aspiration. Foamy samples result in aspiration times shorter than normal. Clotted samples result in aspiration times longer than normal.

Abstract: The present invention provides apparatus and methods for determining the concentration of sample components of a sample by an analytical technique that yields a spectrum that can be written as Y(.omega.)=P(.omega.).multidot.C. The apparatus and methods of the invention account for experimental errors that give rise to distortions in the observed spectrum and that consequently result in inaccurate determinations of sample component concentrations. The invention accounts for such errors by modeling the total experimental error as the sum of one or more types of errors that can be written as .xi..multidot.K. The spectrum is then modeled as Y=P.multidot.C+.xi..multidot.K. Using the observed spectrum, known values for P, and a mathematical model for .xi., this equation can be solved for the best fit value of the sample component concentrations, C, and the magnitudes of the errors, K. The method can be used for any error that can be modeled in the foregoing manner, such as a shift in the spectrum.