U.S. patent application number 10/341051 was filed with the patent office on 2003-06-19 for method and apparatus for determining erythrocyte sedimentation rate and hematocrit.
Invention is credited to Bennett, Michael, Tanasijevic, Milenko J., Winkelman, James W..
Application Number | 20030113930 10/341051 |
Document ID | / |
Family ID | 23871982 |
Filed Date | 2003-06-19 |
United States Patent
Application |
20030113930 |
Kind Code |
A1 |
Winkelman, James W. ; et
al. |
June 19, 2003 |
Method and apparatus for determining erythrocyte sedimentation rate
and hematocrit
Abstract
A method and apparatus is disclosed for determining the
erythrocyte sedimentation rate and hematocrit simultaneously with
the centrifugation of whole blood. A centrifuge separates the whole
blood into its erythrocytes and its fluid portion. A video camera
measures the levels of whole blood, erythrocytes and the fluid
portion of the blood-and records the time of the formation of an
interface between the erythrocytes and fluid portion. A monitor
displays the results of the recording. Also disclosed are the
method steps performed.
Inventors: |
Winkelman, James W.;
(Brookline, MA) ; Tanasijevic, Milenko J.;
(Chestnut Hill, MA) ; Bennett, Michael;
(Cambridge, MA) |
Correspondence
Address: |
Samuels, Gauthier, & Stevens LLP
Suite 3300
225 Franklin Street
Boston
MA
02110
US
|
Family ID: |
23871982 |
Appl. No.: |
10/341051 |
Filed: |
January 13, 2003 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10341051 |
Jan 13, 2003 |
|
|
|
08471536 |
Jun 6, 1995 |
|
|
|
6506606 |
|
|
|
|
Current U.S.
Class: |
436/70 ; 422/72;
422/73; 436/45 |
Current CPC
Class: |
G01N 15/042 20130101;
G01N 15/0211 20130101; G01N 15/05 20130101; Y10T 436/111666
20150115 |
Class at
Publication: |
436/70 ; 436/45;
422/72; 422/73 |
International
Class: |
G01N 033/86 |
Claims
The invention claimed is:
1. A method of calculating erythrocyte sedimentation rate
simultaneously with the centrifugation of whole blood comprising
the steps of: obtaining a sample of whole blood; centrifuging the
whole blood; separating out the erythrocytes; forming an interface
between the erythrocytes and the fluid portion of the blood;
measuring the elapsed time from initiating the step of centrifuging
to the formation of the interface; and calculating the erythrocyte
sedimentation rate of the sample from the elapsed time.
2. A method of calculating hematocrit simultaneously with the
centrifugation of whole blood comprising the steps of: obtaining a
sample of whole blood; loading the sample of whole blood into a
container; measuring the location of the whole blood relative to a
fixed point in the container; centrifuging the blood sample;
separating out the erythrocytes; creating an interface between the
separated erythrocytes and the fluid portion of the blood;
measuring the location of the interface relative to the fixed point
in the container; and calculating the hematocrit of the sample from
the difference between the two locations.
3. A method of calculating erythrocyte sedimentation rate and
hematocrit simultaneously with the centrifugation of whole blood
comprising the steps of: obtaining a sample of whole blood; loading
the sample of whole blood into a container; measuring the location
of the whole blood relative to a fixed point in the container;
centrifuging the whole blood; separating out the erythrocytes;
creating an interface between the erythrocytes and the fluid
portion of the blood; measuring the elapsed time from initiating
the step of centrifuging to the formation of the interface;
measuring the location of the interface relative to the fixed point
in the container; calculating the erythrocyte sedimentation rate of
the sample from the elapsed time; and calculating the hematocrit of
the sample from the difference between the two locations.
4. Method according to claim 1 wherein the step of measuring is
optical.
5. Method according to claim 2 wherein the step of measuring is
optical.
6. Method according to claim 3 wherein the step of measuring is
optical.
7. Method according to claim 1 wherein the step of measuring is by
video camera photography.
8. Method according to claim 2 wherein the step of measuring is by
video camera photography.
9. Method according to claim 3 wherein the step of measuring is by
video camera photography.
10. Method according to claim 1 wherein the step of measuring
includes the steps of recording the time of the formation of the
interface and analyzing the recording optically.
11. Method according to claim 2 wherein the step of measuring
includes the steps of recording the time of the formation of the
interface and analyzing the recording optically.
12. Method according to claim 3 wherein the step of measuring
includes the steps of recording the time of the formation of the
interface and analyzing the recording optically.
13. Method according to claim 1 wherein the step of calculating
includes the steps of analyzing a portion of each sample by
standard techniques and comparing the results for each sample.
14. Method according to claim 2 wherein the step of calculating
includes the steps of analyzing a portion of each sample by
standard techniques and comparing the results for each sample.
15. Method according to claim 3 wherein the step of calculating
includes the steps of analyzing a portion of each sample by
standard techniques and comparing the results for each sample.
16. Method according to claim 1 wherein the step of calculating
includes the steps of analyzing a portion of each sample by
standard techniques, comparing the results for each sample and
plotting the compared results.
17. Method according to claim 2 wherein the step of calculating
includes the steps of analyzing a portion of each sample by
standard techniques, comparing the results for each sample and
plotting the compared results.
18. Apparatus for determining erythrocyte sedimentation rate and
hematocrit simultaneously with the centrifugation of whole blood
comprising: a container for holding a sample of whole blood; a
centrifuge for separating the whole blood into its erythrocytes and
its plasma; means for measuring and recording the volume of whole
blood, the erythrocytes, and the plasma; and a monitor for
displaying the results of the recordings.
19. Apparatus according to claim 18 wherein the measuring and
recording is performed by-a video camera.
20. Apparatus according to claim 18 wherein the measuring is
performed by an optical sensor.
Description
BACKGROUND OF THE INVENTION
[0001] Daily there are hundreds of thousands of samples of blood
drawn in hospitals, medical clinics and doctors' offices for
analytical purposes. Some of this blood is analyzed directly as
whole blood without being processed. Some is analyzed after
separation of the cellular components of the blood (e.g.,
leukocytes and erythrocytes) from the fluid portion of the blood
(plasma or serum).
[0002] For example, whole blood can be used for hematological
analysis to measure the total concentration of red blood cells and
white blood cells in the whole blood, or to prepare blood smears
for microscopic analysis of the different types of cells that are
present in the blood. Microscopic analysis can be used to diagnose
a number of different diseases that might be present, such as
certain types of leukemias or anemias. Very commonly, the patient
will have a complete blood count (CBC) performed on a whole blood
sample. A CBC typically includes a red blood cell (RBC) count, a
white blood cell (WBC) count, a differential white blood cell count
to identify the types of white blood cells present, a platelet
count and the determination of blood parameters such as total
hemoglobin and hematocrit.
[0003] Alternatively, whole blood can be processed to separate the
cellular components from the fluid portion to obtain serum or
plasma. Initially, blood is drawn from a patient into a small glass
tube. If the tube contains an anticoagulant, the blood does not
coagulate (i.e., form a clot) and the cells remain "suspended" in
the plasma. If the tube does not contain an anticoagulant, the
blood coagulates. The formation of a clot removes certain protein
components from the plasma, with serum remaining as the fluid
portion of the blood. Processing whole blood to separate cells from
plasma/serum is typically accomplished by centrifugation.
[0004] Analysis of other physiological parameters can be performed
on the plasma or serum, per se, which contain extracellular
components such as proteins, hormones and electrolytes. A patient
undergoing a general physical examination will probably have tests
performed on both serum and plasma.
[0005] Erythrocyte sedimentation rate (ESR) is one of the
traditional tests performed on whole blood in hematology
laboratories. ESR measures the distance red blood cells sediment,
or fall, in a vertical tube over a given period of time. The
measurement of sedimentation is calculated as millimeters of
sedimentation per hour and takes greater than one hour to complete.
The principle behind ESR is that various "acute phase" inflammatory
proteins can affect the behavior of red blood cells in a fluid
medium (e.g., decrease the negative charge of RBCs). Inflammatory
proteins, such as fibrinogen, will typically appear in the blood,
or increase in concentration, during inflammatory processes, such
as arthritis. The result is decreased negative charge
(zeta-potential) of the erythrocytes that tends to keep them apart,
and a more rapid fall of the cells in the analysis tube. The
greater the fall of red blood cells in the vertical tube measured
at a given period of time, the higher the ESR. A high (i.e.,
elevated) ESR is indicative of the presence of inflammatory
proteins, (i.e., an active inflammatory processes, such as
rheumatoid arthritis, chronic infections, collagen disease and
neoplastic disease).
[0006] The process of collecting the blood specimen and the
particular anticoagulant used are crucial in determining an
accurate ESR. For example, in one well-known technique known as the
Westergren method, blood is collected in the presence of the
anticoagulant, sodium citrate, whereas in the modified Westergren
procedure, EDTA is used as the anticoagulant. The modified
Westergren procedure has become the standard for measuring ESR
because it allows the ESR to be performed from the same tube of
blood as is used for hematologic studies. Essentially, ESR is a
test that has been practiced for decades without much change in the
procedure.
[0007] Hematocrit (HCT) or packed red blood cell volume is the
ratio of the volume of red blood cells (expressed as percentage or
as a decimal fraction) to the volume of whole blood of which the
red blood cells are a component. In the micromethod for determining
hematocrit, tubes containing whole blood are centrifuged for 5 min
at 10-12000 g to separate the whole blood into red cells and
plasma. The hematocrit is calculated from the length of the blood
column, including the plasma, and the red cell column alone,
measured with a millimeter rule. One of the problems with this
technique is that it's time consuming and erroneous results may
occur as a result of incorrect reading of the levels of cells and
plasma or if a significant concentration of plasma becomes trapped
within the red cell layer.
[0008] It is an object of this invention to measure both
erythrocyte sedimentation rate and hematocrit simultaneously with
the centrifugation of the whole blood specimen, which is performed
for other purposes. In other words, the object is to obtain two
critically important blood parameters during the routine
centrifugation that is almost universally performed on every blood
sample drawn for analytical purposes, without additional
manipulation or handling of the blood sample.
[0009] Another object is to perform these determinations as rapidly
as possible, and have results available much faster than with
currently practiced methods.
SUMMARY OF THE INVENTION
[0010] The invention resides in a method of calculating the
erythrocyte sedimentation rate and hematocrit simultaneously with
the centrifugation of whole blood for other purposes and apparatus
for performing the method.
[0011] A sample of whole blood is collected in a container in the
presence or absence of an anticoagulant. With the dimensions of the
container known, the volume is ascertainable by the blood's level
in the container. Thus, the blood level relative to a fixed point
in the container need only be measured. A sample is centrifuged to
create an interface between the erythrocytes and the plasma or
serum. The location of the interface relative to a fixed point in
the container is measured as well as the elapsed time between
initiating the centrifugation of the blood and the time the
interface between the erythrocytes and the plasma or serum is
formed. The time and dimensional factors are measured optically and
permanently recorded. The erythrocyte sedimentation rate of the
sample is calculated from the elapsed time and the hematocrit of
the sample is calculated from the difference between the two
measured locations.
[0012] The step of measuring the location of the original sample,
the interface and the elapsed time of forming the interface is
performed by a video camera which records on tape and which is
monitored by a video monitor.
[0013] A chart comparing the results of measuring erythrocyte
sedimentation rate by standard known techniques and that obtained
by the above-described method was made to show the correlation of
the two techniques. Thereafter, the chart may be referred to in
order to obtain erythrocyte sedimentation rate expressed in
millimeters per hour (conventional manner) from a measurement of
the elapsed time (expressed in seconds) for interface
formation.
[0014] The above and other features of the invention including
various and novel details of construction and combination of parts
will now be more particularly described with reference to the
accompanying drawings and pointed out in the claims. It will be
understood that the particular method and apparatus for determining
erythrocyte sedimentation rate and hematocrit embodying the
invention is shown by way of illustration only and not as a
limitation of the invention. The principles and features of this
invention may be employed in varied and numerous embodiments
without departing from the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a schematic showing of apparatus for determining
erythrocyte sedimentation rate and hematocrit by optical
measurement.
[0016] FIG. 2 is a top plan view on enlarged scale of a centrifuge
rotor employed with the apparatus.
[0017] FIG. 3 is a partial sectional view of the rotor shown in
FIG. 2.
[0018] FIG. 4 is a detail sectional view of the rotor on a smaller
scale.
[0019] FIG. 5 is a front view of a video monitor employed with the
apparatus.
[0020] FIG. 6a is a view of the monitor showing a blood sample
before centrifugation.
[0021] FIG. 6b is a schematic showing of the rotor 4 corresponding
to FIG. 6a with the blood sample before centrifugation.
[0022] FIG. 7a is a view of the monitor showing the blood sample
during centrifugation.
[0023] FIG. 7b is a schematic showing of the rotor 4 corresponding
to FIG. 7a showing the blood sample during centrifugation.
[0024] FIG. 8a is a view of the monitor after the erythrocytes and
plasma have been separated.
[0025] FIG. 8b is a showing of the rotor 4 corresponding to FIG. 7a
after the erythrocytes and plasma have been separated.
[0026] FIG. 9 is a chart of ESR expressed as time (sec) to
formation of the cell/plasma interface, plotted against ESR in
millimeters per hour measured by traditional technique.
[0027] FIG. 10 is a schematic view of a blood separation tube
equipped with an optical sensor (after centrifugation).
[0028] FIG. 11 depicts one type of a blood separator tube after
centrifugation where the red blood cells penetrated thixotropic gel
in the tube.
[0029] FIG. 12 is a view similar to FIG. 10 after centrifugation
where the red blood cells have not penetrated the gel.
[0030] FIG. 13 is a schematic view of another embodiment of the
centrifuge.
DETAILED DESCRIPTION OF THE INVENTION
[0031] Referring to FIG. 1, apparatus is schematically illustrated
for determining sedimentation rate of whole blood simultaneously
with centrifuging blood for other purposes. A small, high-speed,
bench top centrifuge 2 mounts a rotor 4 within a transparent shield
5 for rotation on a vertical axis .alpha.. One such centrifuge is
sold under the name Stat-Spin.RTM. by StatSpin Technologies of
Norwood, Mass. A high speed video camera designated NAC HSV-300 is
mounted for vertical adjustment on a stand 8. A continuous light 7
is mounted to project on the rotor 4. An output cable 10 of the
camera having a plug 12 leads to a video tape recorder (not shown)
and a monitor 24 seen in FIGS. 5 to 8b.
[0032] Secured to the video camera 6 is a lens extension bellows 9,
made by the Nikon Company and designated PB-6E. On the forward or
lower end of the bellows is a 105 mm f.1.8 Nikkor lens. During
testing, the bellows was set with an 85 mm extension. The lens,
through the bellows extension, was 165 mm from the shutter of the
video camera 6. The front element of the lens was positioned 240 mm
from the centrifuge rotor 4.
[0033] The rotor 4 will be seen in more detail in FIG. 4. It is a
commercial, circular rotor also made by Stat-Spin Technologies and
includes an outer circular flange or rim 14 tapering downwardly and
outwardly as viewed in FIG. 4 from a central conical portion 16
having a concave bottom 18. The interior of the flange ends at a
circular wall 30. The rotor fits on a rotor holder 20 secured by an
expandable rubber "O" ring 19. A downwardly, extending projection
21 of the holder 20 secures the rotor holder in the body of the
centrifuge 2. The central uppermost portion of the rotor 4 is
plugged with a removable stopper 22 (FIG. 3).
[0034] The video monitor 24 as shown in FIG. 5 is of a standard
commercially available type measuring 270 mm wide and 200 mm high.
A time code window 26 appears in the upper right hand corner of the
screen of the monitor 24 and a specimen identification window 28 is
in the upper left hand corner.
[0035] Two hundred samples of whole blood from actual hospital
patients were analyzed by the conventional modified Westergren
technique. A one ml aliquot from each of the prepared whole blood
samples was pipetted into its own separate plastic rotor 4 of the
type shown in FIGS. 3 and 4. Each rotor was, in turn, loaded onto
the bench top centrifuge 2. The high speed video camera 6 and the
strobe light 7 were turned on and centrifugation begun. For each
sample, the rotor 4 was spun at 3,500 rpm and the samples were
continuously illuminated. The video camera recorded at 200
frames/sec with {fraction (1/200)} sec exposure time. The elapsed
time in seconds of rotation for each sample was recorded on the
video tape within the camera 6 and shown in the time code viewer
26. The time required for the plasma and the red blood cells to
form an interface was obtained from the readout of the time code
window 26 and by viewing the video tape played back in slow motion.
The results were recorded by sample-by-sample as will be described
in greater detail hereinafter.
[0036] As can be seen in FIGS. 6a-8b, the relationship between the
whole blood (hereinafter designated C+P for cells plus plasma) in
the rotor 4 relative to the view on the monitor (and thus the tape)
is illustrated. Initially, the whole blood sample was collected in
the presence of an anticoagulant, well mixed and placed in the
rotor 4. It is shown crosshatched in FIGS. 6a and 6b. It forms a
uniform ring against the inner circular wall 30 of the rotor. The
opposite circular edge or height of the blood sample is designated
35. The whole blood appears on the monitor screen as a single wide
curved band, designated C+P in FIG. 6a and extending from circular
band 35 to circular band 30.
[0037] As seen in FIGS. 7a and 7b, in the initial phase of
separation, an interface I begins to form between the blood cells C
and the plasma P. In other words, the red blood cells C begin
moving away from the plasma P.
[0038] The interface I migrates progressively outwardly of the axis
a of the rotor 4 toward the circular inner wall 30 of the rotor 4.
However, when all of the cells C have been separated from the
plasma P, the interface I between the cells C and the plasma P
reaches a terminal point I.sub.t seen on the screen as a curved
line between the bands of plasma P and the cells C. The elapsed
time between the initial start of the centrifugation and the time
to complete separation (I.sub.t) is determined by the operator
reading the time code on the video monitor 26. It is also
permanently recorded on the tape for future reference. The actual
time of the complete migration of the cells from the plasma was
subsequently checked by viewing the video tape in slow motion in
the playback mode.
[0039] The formation of the terminal interface I.sub.t between the
plasma P and the blood cells C was found to be completed within the
first 20-45 seconds of centrifugation at 3,500 rpm.
[0040] Of the two hundred samples of blood, the ESR of a portion of
each sample was measured by the conventional modified Westergren
method and of another portion by elapsed time measured as described
above. The results for each sample were plotted as will be seen in
FIG. 9. The time required for the interface formation in the
centrifuge inversely correlated with the ESR obtained by the
modified Westergren method. The study indicated that measuring ESR
by the centrifugation method was not only simpler but much quicker
than measuring by the modified Westergren method.
[0041] The best fit curve depicted in FIG. 9 is valid for the
particular apparatus employed. Consequently, if an operator were
using the same apparatus, it is only necessary for him to
centrifuge blood until the terminal interface (I.sub.t) is formed,
record the elapsed time for centrifugation, locate the time on the
best fit curve (BFC) and read downwardly to determine the
erythrocyte sedimentation rate in millimeters per hour. This could
also be done instrumentally.
[0042] The above described method represents a simple and quicker
alternative to the standard modified Westergren method and may be
employed with plastic or glass tubes or other containers containing
thixotropic gel, or gel-free tubes or other containers, since the
interface formation takes place before the red cells penetrate the
gel separation layer.
[0043] The same general technique may be employed to ascertain
hematocrit (HCT) as is used for ascertaining erythrocyte
sedimentation rate (ESR). In determining hematocrit, instead of
measuring the elapsed time it takes to form the terminal interface
I.sub.t, the quantity of separated red blood cells is measured. As
stated above, hematocrit (HCT) or packed red blood cell volume is
the ratio of the volume of the red blood cells to the volume of the
whole blood from which the cells were separated. It may be
expressed as a percentage or as a decimal fraction.
[0044] When our technique is employed using the circular rotor 4 as
the container for the whole blood being centrifuged, the video
camera 6 initially records the location of the circular edge 35 of
the whole blood, i.e. its radial distance from the axis of rotation
.alpha. of the rotor. After centrifugation, the video camera
measures the location of the terminal interface I.sub.t radially
from the axis of rotation .alpha..
[0045] Since hematocrit (HCT) is defined as the volume of the red
blood cells divided by the volume of the whole blood from which it
was separated, hematocrit maybe calculated as follows: The distance
from the axis .alpha. (see FIG. 6b) to the circular inner wall 30
of the rotor 4 is known. The distance from the axis .alpha. to the
interface I.sub.t (see FIG. 8b) is measurable and the distance from
the axis .alpha. to the original circular edge of the whole blood
35 is measurable. Under ideal circumstances, the HCT would be
directly calculable to the two measured distances. The numerator of
the fraction would be the distance from axis .alpha. to the wall 30
minus the distance from the axis .alpha. to the terminal interface
I.sub.t. The denominator would be the distance from the axis
.alpha. to the wall 30 minus the distance from the axis .alpha. to
the edge 35 of the whole blood. This, however, is only true if the
interior of the rotor 4 were uniform, but as will be seen in FIG.
4, it is not. Accordingly, the result must be adjusted by a
constant or a formula to correct for the irregular configuration.
This could lead to complex mathematical calculation.
[0046] Another way to compensate for this irregularity is to print
on the rotor 4 as seen in FIG. 2 a series of concentric rings
R.sub.1, R.sub.2, R.sub.3, etc. which are representative of
constant volumes of the interior of the rotor. For example, the
rotor's volume may be designated in tenths by printing on its
surface ten concentric rings R.sub.1 to R.sub.10. The rings would
not be uniformly spaced per se. Their spacing would be determined
by the mathematical formula of the internal value of the rotor
divided successively by tenths.
[0047] A preferred technique, however, is to employ a modified
bucket-type centrifuge where the sample containers 56 are
conventional commercially available blood centrifuging test tubes
of constant diameter and pre-loaded with a quantity of thixotropic
gel G (FIGS. 10 and 12). The test tube 56 containing a sample of
blood (collected in the presence or absence of an anticoagulant) is
placed in the centrifuge 50 (to be described in greater detail
hereinafter). As seen in FIG. 11, after centrifugation, the red
blood cells C penetrate the gel G and collect at the base of the
test tube. The hematocrit is calculated as follows: 1 H c t = a - c
b - c
[0048] where c is a constant representing the height of the gel
G.
[0049] Alternatively, the above calculation could be based upon the
relative heights of the red blood cells and the plasma measured
before the red blood cells C penetrate the gel G as seen in FIG.
12. The formula would then be: 2 H c t = ( h ) C ( h ) C + ( h )
P
[0050] Expressed alternatively, HCT is the height of the red blood
cells divided by the height of red blood cells plus height of
plasma, ignoring the gel. Another alternative way of expressing the
result is the sum of the heights of red blood cells and height of
gel divided by the collective height of the plasma, the red blood
cells and the gel.
[0051] FIG. 13 is a schematic diagram of a centrifuge employing a
conventional integrated serum separated tube style of the type sold
under the trade name CORVAC by Sherwood Medical, St. Louis, Mo. for
performing the techniques described with reference to FIGS. 11 and
12. The centrifuge may be positioned below the video camera 6 of
the type shown in FIG. 1. It has a base 50 and an upstanding rotor
shaft. 52. A gimbel 54 is pivoted at 58 on the rotor shaft 52. The
separator tube 56 is gripped by a clamp of the gimbel 54. A
counterweight 60, if needed, may also be pivotally mounted on the
rotor shaft 52. The centrifuge is rotated at 3500 RPM for about
three minutes. During centrifugation, the separator tube 56 being
mounted by the gimbel 54 attains a horizontal position that is
indicated by the dotted line .beta. in FIG. 13 whereupon it is in
the best possible position to be photographed by the video camera
6, i.e. with the tube 56 at right angles to the axis of the lens of
the video camera.
[0052] The video camera measures and records the distance from the
bottom of the separator tube 56 to the gel/plasma interface
designated a in FIG. 11. It also measures distance from the bottom
of the tube 56 to the plasma air interface designated b in FIG. 10.
The same type of measurement would apply to FIG. 12.
[0053] The HCT measurement can be performed separately or following
the sedimentation rate determination described above since the
sedimentation rate is ascertained in the first 20 to 45 seconds of
centrifugation.
[0054] Another possible embodiment is disclosed in FIG. 10 wherein
the separator tube 56, which would be centrifuged by apparatus
similar to that shown in FIG. 13, would include an optical source
and sensor 62 associated with the tube. Lead wires 64, 66 would
lead to a microprocessor (not shown) which would continuously feed
data to the tape and the video monitor 24, or other means of
detecting the interface formation by its optical properties. By use
of this technique, the video camera and strobe are eliminated and a
plurality of separated tubes could be centrifuged simultaneously
and the results recorded simultaneously.
* * * * *