Coulter Counter Model Research Articles

A Temporary Lyses Chamber for the Coulter Counter Model S

A Temporary Lyses Chamber for the Coulter Counter Model S

Pseudoleukocytosis due to cryoprotein crystals.

A patient with a spontaneously crystallizing IgG paraprotein was found to have leukocytosis when cell counts were determined by the Coulter Counter Model S. The appearance of large crystals on the smear prepared from blood at room temperature suggested that the apparent increase in leukocyte count was due to the enumeration of crystals. This presumption was established by further studies. Reliable automated counts could be obtained by prewarming the blood specimen to 37 C.

The Preservation of Leukocytes in Stored Blood

Abstract. Leukocyte counts in EDTA blood samples stored in an ordinary refrigerator remain stable for 2 weeks when assayed with the Coulter Counter Model S.

Cold agglutinins and the Coulter Counter Model S.

Cold agglutinins and the Coulter Counter Model S.

A Unopette Test for the Coulter Counter Model S

Unopettes have been widely used for rout ine hematology, platelet determinations, and more recently, circulating eosinophils. The Unopette (Becton-Dickinson and Company, Rutherford, N.J.) used with the Coulter Counter Model S (Coulter Electronics, Hialeah, Fla.) is a diluting device that consists of a reservoir which contains 10 ml. of stable modified Eagle's solution and is supplied with a self-measuring, self-fi l l ing 44.7 microliter pipette wh ich , when used in conjunction with the diluent reservoir, renders a 1:224.7 dilution. Details of the procedure are as follows: 1. Blood is drawn in the usual manner by either finger puncture technique using the 44.7 microliter pipette or by taking this same aliquot from a blood specimen anticoagulated with EDTA. 2. The outside port ion of the pipette is wiped free of excess blood

Evaluation of the Coulter counter Model S

Evaluation of the Coulter counter Model S

A stromatolysing and cyanide reagent for use with the Coulter counter model S.

A stromatolysing and cyanide reagent for use with the Coulter counter model S.

Spurious erythrocyte indices as measured by the model S Coulter counter due to cold agglutinins.

Brittin and associates reported that the spurious macrocytosis caused by antibody-coated erythrocytes did not occur when this parameter was measured by the Coulter counter model S. We have encountered at least two definite cases in which spurious macrocytosis as well as spurious mean corpuscular hemoglobin concentration and mean corpuscular hemoglobin values were obtained using this instrument. These were due to cold agglutinins. The clue to each of these cases was a mean corpuscular hemoglobin concentration of more than 36%. The combination of this finding with elevated mean corpuscular volume and mean corpuscular hemoglobin values should prompt a search for cold agglutinins.

An assessment of the Coulter counter model S.

An assessment of the Coulter model S automatic blood counter has been carried out. The standard deviations for the haemoglobin concentration, haematocrit, red cell count, and white cell count are, respectively, +/- 0.15 g/100 ml, +/- 0.45%, +/- 0.04 m/c mm, and +/- 0.47 thous/c mm. These results are clearly more accurate than careful manual estimates, performed for comparison on the same samples. Details of the comparisons are presented. A comparison is also made with routine daily estimations.;Carryover' from one sample to the next was found to be about 2%, and tests in the ranges likely to be found in practice showed good linearity for the haemoglobin estimation, haematocrit, red cell count, and white cell count. A brief account of instrument failures is given.The performance of the Coulter model S compares well with that of other automated equipment for which detailed evaluations are available.

Some observations on the use of the coulter counter model B in coagulation studies

The use of the Coulter counter model B in coagulation studies is critically evaluated. The significance of calibration, accurate sizing, particle concentration, orifice tube breakup, sedimentation, coincidence, and dilution is considered. The implications of the effect of coarsening of the suspension on the detection of small particles are discussed.

Data Suppression on the Coulter Counter Model S

Data Suppression on the Coulter Counter Model S

Elimination of Error in Hematocrit Produced by Excessive EDTA

Brittin, Geoffrey M., Brecher, George, and Johnson, Carole A.: Elimination of error in hematocrit produced by excessive EDTA. Experience with the Coulter Counter Model S. Techn. Bull. Reg. Med. Techn., 39: 246–249, 1969. We have studied the effects of excessive disodium EDTA on the hematocrit value as determined by the conventional micromethod and by the Coulter Counter Model S, which measures hematocrit indirectly as the product of the red cell count and the mean cell volume. We have also studied a commercial cell control for the Model S which simulates whole blood but crenates the red cells by suspension in a hypertonic medium. Both whole blood with excess EDTA and the commercial cell control give lower hematocrits by the conventional method than when measured by the Model S Coulter Counter. The Model S gives the correct hematocrit value because the 1:50,000 dilution of blood in isotonic medium restores the shrunken red cells to their initial size. It is of practical interest that excess EDTA, which shrinks red cells in proportion to the excessive concentration of anticoagulant and thereby gives erroneously low hematocrit values when determined by the conventional micromethod, does not produce an error in the hematocrit value when it is determined by the Coulter Counter Model S.

Evaluation of the Coulter Counter Model S

We have evaluated the prototype and production models of the Coulter Counter Model S over an 11-month period. The built-in diluting system had a precision of better than 1 %. The precision and stability of the production instrument were superior to those of our reference methods. Correspondence of the results of the Model S and those of the routine clinical laboratory was excellent over a 6-week period. Elevated white cell counts produced a small positive error in the hemoglobin determination proportional to the number of white blood cells (WBC). The major difficulties in the use of the instrument were specimen interaction (“carryover”), calibration, and quality control. We have investigated these difficulties and found that they produce no serious limitations in the use of the instrument. Our findings suggest that if other instruments achieve the same performance specifications obtainable with ours, the Coulter Counter Model S represents a major advance in medical instrumentation.

Stability of blood in commonly used anticoagulants. Use of refrigerated blood for quality control of the Coulter Counter Model S.

We studied the stability of blood collected into four commonly used anticoagulants at refrigerator and room temperatures. Blood collected into tripotassium or disodium ethylenediaminetetraacetate was stable for 24 hr. in the refrigerator for white and red blood cell counts, hemoglobin, hematocrit, mean cell volume, mean cell hemoglobin, and mean cell hemoglobin concentration, determined both by conventional methods and by the Coulter Counter Model S. In all four anticoagulants studied there was slight swelling of the red cells on storage at room temperature. The stability of refrigerated blood collected into ethylenediaminetetraacetate permits the use of stored patient specimens as a test material for quality control of the Model S. We have introduced a practical method, which has advantages over the use of commercial cell controls.

Spurious Macrocytosis of Antibody-Coated Red Cells

Brittin, Geoffrey M., Brecher, George, Johnson, Carole A., and Stuart, John: Spurious macrocytosis of antibody-coated red cells. Techn. Bull. Regist. Med. Techn., 39: 149–153, 1969. We have found that the mean cell volume (MCV) of red cells in autoimmune hemolytic anemia or after sensitization in vitro may form “microagglutinates” of doublets and triplets, even in a 1:50,000 dilution. In such circumstances, electronic counters which register agglutinates as single particles give erroneously low red cell counts (RBC), and the MCV computed as a ratio of hematocrit to this RBC is falsely elevated. Our findings indicate that even vigorous manual mixing of a 1:50,000 dilution of sensitized red cells is not sufficient to produce the correct RBC with the Coulter Counter Model A. In contrast, sensitization of red cells does not produce a change in their MCV when determined with the Coulter Counter Model S, presumably because its efficient automatic mixing system breaks apart the “microagglutinates.” True macrocytosis is known to be associated with hemolytic anemia; but the finding of a very high MCV, when determined by electronic counters other than the Coulter Counter Model S, is suggestive of red cell agglutination, and a Coombs test is indicated.

Automatic platelet counting with the Couler particle counter.

A method for accurately counting platelets is described using the Coulter counter model B fitted with a standard 100mu aperture tube. This enables the counter to be used for red and white cell as well as platelet counts using the same aperture tube. The method uses standard equipment except for a small inexpensive electronic speed controller.

ELECTRICAL COUNTING CHARACTERISTICS OF SEVERAL EQUIVOLUME MICRO-ORGANISMS.

Several micro-organisms of similar initial size (0·25μ3) were used to study the intra-species and inter-genus variations in the electronic counting characteristics and population distribution as functions of culture age. A Coulter Counter Model A was used to count populations of Staphylococcus aureus sm, Escherichia coli (Sias), an E. coli variant, E. freundii (8454), and an E. freundii variant. Initial inocula into brain heart infusion broth were from agar slopes. Cultures were incubated at 37° for various growth periods from 4 to 24 hr.; centrifuged at 1500 g for 25 min, and the deposit resuspended in 0·9% (w/v) NaCl twice, then resuspended in 10 ml. saline, diluted 1/104, shaken, and counted in the Coulter counter at maximum gain on aperture current settings (a.c.s.) 4, 5 and 6 with threshold settings from 5 to 100. Population distributions were made with a phase-contrast microscope in a Petroff-Hauser counting chamber. The numbers of aggregates containing 1, 2, 3, 4 and > 4 organisms were recorded as percentage of total populations. Counts were established for all bacterial populations tested as well as for the 0·81 μ diameter latex sphere counting standard. With a technique based on the addition of random variables, true bacterial population counts could be formulated. Some of the actively dividing populations displayed characteristic sensitivities which were dependent in part on the aperture current setting. It is concluded that intra-species as well as inter-genus variations exist. These variations are the result of factors such as: The given organism, its age, distribution and growth rate at the time of count, dilution and counting media, aperture diameter and magnitude of the current field in the electronic counting system.