CAPILLARY-VENOUS DIFFERENCES IN BLOOD GLUCOSE VALUES
DURING THE ONE-HOUR, TWO-DOSE GLUCOSE TOLERANCE
TEST (EXTON-ROSE PROCEDURE)
PAUL H. LANGNER, JR. AND HARRY L. FIES
From the Clinical Laboratory of the Provident Mutual Life Insurance Company of Philadelphia
Significant capillary-venous differences in blood glucose values during the
one-dose glucose tolerance test have been repeatedly demonstrated. It seemed
worthwhile to ascertain whether similar differences occurred during the one-hour,
two-dose glucose tolerance test. We wish to present data showing that significant capillary-venous differences do occur during the two-dose test and that
these differences may influence the interpretation of results.
Hagedorn1 in 1921 observed that when a person is fasting the concentration of blood
sugar is equally high in arterial and venous blood but after the ingestion of carbohydrates
the rise is considerably higher in arterial than in venous blood. This is attributed to the
fact that during circulation through the capillaries a removal of blood sugar in the peripheral tissues takes place.
Foster2 confirmed these findings in 1923 and found that the arterial blood was practically
equivalent to blood obtained from the finger (capillary blood). He found the maximum
capillary-venous difference, after the ingestion of glucose, in his series of determinations to
be about 80 mg. per cent.
Rabinowitch3 obtained similar results in normal individuals but found that in diabetics
the capillary-venous differences were less. In fact, in severe diabetes the usual relationship
was reversed so that the venous blood sugar might actually be higher than the arterial
blood sugar. His maximum capillary-venous difference, after the ingestion of glucose, in
normal individuals was 80 mg. per cent with an average difference of 53 mg. per cent.
Marble, Joslin, Dublin, and Marks4 have also found a capillary-venous difference as
great as 80 mg. per cent.
Friedenson, Rosenbaum, Thalheimer, and Peters 6 found the range of capillary-venous
difference, one-half hour after the ingestion of 50 grams of glucose, to be from 8 to 50 mg.
per cent with an average of 21 mg. per cent. At one hour the average difference was 13
mg. per cent and at two hours only 7 mg. per cent. These authors also demonstrated that
the administration of insulin to normal individuals in the fasting state caused a greater fall
in capillary blood glucose than in venous blood glucose.
Cavett and Seljeskog6 found the fasting blood sugar to be identical in capillary and
venous blood. During the hyperglycemia which follows the administration of glucose, a
capillary-venous divergence was usually present in normal subjects. After one-half hour
the maximum difference was 42 and the average 14 mg. per cent; at two hours the maximum
difference was 36 and the average 12.3 mg. per cent. The capillary and venous blood glucose
values were usually the same by the end of three hours. These authors state that squeezing
the finger to obtain the capillary samples causes no appreciable variation in the result.
We have obtained similar findings in 20 individuals during the one-dose, two-hour
test. (See table 1).
95
TABLE 1
SIMULTANEOUS CAPILLARY AND V E N O U S BLOOD SUGAR V A L U E S DURING T H E
TWO-HOUR,
O N E - D O S E TOLERANCE T E S T
(Figures expressed as milligrams per 100 c.c. of blood)
PASTING
AVERAGE
CAPILLARYVENOUS
DIFFERENCE
J HOUR
AVERAGE
CAPILLARYVENOUS
DIFFERENCE
2 HOUR
AVERAGE
CAPILLARYVENOUS
DIFFERENCE
E. B.
c*100
c 102
v* 97
v 101
2
190
191
176
174
16
123
124
123
125
0
W. T. M.
c
c
v
v
90
90
85
90
2
168
168
156
153
13
112
111
107
103
7
H. R.
c 97
c 97
v 103
v 100
-5
196
199
173
178
22
200
194
190
187
8
H. V. L.
c 102
c 100
v 100
v 92
5
164
167
130
132
35
145
140
125
115
23
C. H.
c
c
v
v
80
80
80
83
-2
130
135
120
118
14
125
125
100
95
27
J. R.
c
c
v
v
95
90
86
90
5
145
150
120
120
28
105
103
95
98
7
J. P. G.
c
c
v
v
105
108
108
110
-2
205
200
190
190
13
135
135
107
103
30
J. A. P.
c
c
v
v
110
111
114
111
-2
189
191
170
181
14
95
94
102
100
-6
H. S.
c
c
v
v
80
84
79
78
3
120
120
102
102
18
68
70
68
66
2
W. W. S.
c
c
v
v
98
95
95
96
1
130
130
121
124
7
97
95
89
92
5
|
96
TABLE 1—Concluded
FASTING
M. B.
AVERAGE
CAPILLARYVENOUS
DIFFERENCE
c
c
v
v
90
94
95
95
-3
D. W.
c
c
v
v
88
92
95
97
G. S. M.
c
c
v
v
W. H. B.
JHOUR
AVERAGE
CAPILLARYVENOUS
DIFFERENCE
2 HOUK
AVERAGE
CAPILLARYVENOUS
DIFFERENCE
115
120
108
112
8
-6
130
132
116
118
14
95
97
89
89
7
91
91
90
91
0
133
135
132
132
2
83
80
69
70
12
c
c
v
v
105
106
109
109
-3
167
163
140
138
26
185
182
182
183
1
L. D.
c
c
v
v
83
85
80
80
4
182
191
153
150
35
62
60
60
1
J. P. G.
c
c
v
v
112
113
113
113
0
199
202
180
185
18
106
106
104
102
1
J. P.
c 107
c 104
v 90
v 94
14
186
181
149
149
35
115
117
94
94
22
H. L. F.
c
v
70
73
-3
108
114
4
85
81
4
P. H. L.
c
v
80
76
4
138
126
12
85
80
5
J. R.
c
c
v
v
96
92
90
90
4
166
170
146
143
23
92
90
85
83
7
Average difference
Maximum difference
0.9
14
83
1
83
80
17.8
35
c* = capillary blood,
v* = venous blood.
The above individuals received one dose of 50 grams of glucose.
97
7.3
30
TABLE 2
SIMULTANEOUS CAPILLARY AND VENOUS BLOOD SUGAR VALUES DURING THE ONE-HOUR,
TWO-DOSE TOLERANCE TEST
(Figures expressed as milligrams per 100 c.c. of blood)
FASTING
AVERAGE
CAPILLARYVENOUS
DIFFERENCE
J HOOT
AVERAGE
CAPILLARYVENOUS
DIFFERENCE
1 HOUR
AVERAGE
CAPILLARYVENOUS
DIFFERENCE
W. T. M.
C*92
c 90
v*90
v 90
1
164
169
150
150
17
196
194
176
180
17
H. R.
c
c
v
v
96
94
93
91
3
165
165
159
160
5
176
180
168
163
12
W. H.
c 92
4
150
153
140
144
10
166
160
154
155
9
-2
143
145
134
135
9
188
192
161
161
29
v 90
v 85
J. R.
c 93
c 100
v 98
vlOO
E. S.
c
c
v
v
95
95
92
88
5
203
200
200
200
2
270
277
263
263
11
c. w. s.
c
c
v
v
96
93
94
95
0
158
167
144
149
16
200
202
184
189
14
B. S.
c
c
v
v
83
84
86
82
0
125
128
98
93
31
120
125
93
88
32
L. C. S.
c
c
v
v
88
87
95
93
-6
151
152
150
149
2
159
155
132
139
21
J. L. V.
c
c
v
v
82
83
82
80
2
135
140
130
127
9
170
174
135
135
37
A. E. S.
c
c
v
v
93
93
86
85
7
155
160
158
157
0
178
179
176
179
1
98
TABLE 2—Continued
TASTING
AVEJtAGE
CAPILLARYVENOUS
DIFFERENCE
J HOUR
AVERAGE
CAPILLARY-j
VENOUS
DIFFERENCE
1 HOUR
AVERAGE
CAPILLARYVENOUS
DIFFERENCE
E. B.
C
c
v
v
90
94
90
86
4
173
171
170
170
2
190
200
180
186
12
T. D. C.
c 115
c 113
vll2
vll5
0
182
175
190
179
-6
258
250
255
250
1
H. L. C.
c
c
v
v
85
88
88
87
-1
134
133
130
125
6
154
154
157
150
0
E. D.
c
c
v
v
86
85
91
90
-5
122
120
100
99
21
98
101
86
87
13
L. D.
c
c
v
v
95
94
85
88
8
190
195
170
170
23
228
228
210
210
18
W. G.
c
c
v
v
83
83
80
82
2
125
135
120
117
11
112
120
86
87
29
J. P. G.
c 113
c 122
vll8
vll9
-1
221
221
190
190
31
226
229
175
171
55
C. H.
c
c
v
v
88
86
82
82
5
170
164
140
142
26
146
149
110
108
39
T. L.
c
c
v
v
90
92
86
89
3
140
138
119
120
19
138
135
106
110
29
J. J. M.
c 95
c 102
vlOO
v 98
0
226
221
200
206
21
305
305
245
250
57
R. E. 0 .
c 107
c 107
vlOO
vl03
5
210
218
195
189
22
170
165
155
150
15
99
TABLE 2—Concluded
FASTING
AVERAGE
CAPILLARYVENOUS
DIFFERENCE
i HOUR
AVERAGE
CAFILLARYVENOUS
DIFFERENCE
1 HOUR
AVERAGE
CAPILLARYVENOUS
DIFFERENCE
-2
150
158
153
150
2
224
220
190
194
30
95
99
95
96
1
169
171
133
141
33
169
172
135
139
34
c
c
v
v
98
90
96
93
-1
165
165
152
150
14
182
182
175
170
9
H. D.
c
c
v
v
104
107
98
94
10
176
170
152
149
22
159
158
135
128
27
J. P.
c
c
v
v
90
92
86
80
8
155
159
149
151
7
182
180
160
158
22
W. T. M.
c
c
v
v
88
89
88
90
0
187
186
175
175
12
200
205
192
191
11
M. K.
c
c
v
v
98
98
90
90
8
111
110
96
97
14
110
110
83
85
26
K. B.
c 103
v 92
11
176
150
26
C. N. S.
c 75
v 79
-4
167
159
8
193
175
18
L. S.
c 67
v 77
-10
162
150
12
160
144
16
F. C. B.
c 85
v 80
5
194
166
28
172
168
4
J. S. P.
c 105
c 102
vl08
vl03
J. R.
c
c
v
v
H. V. L.
Average difference
Maximum difference
c* = capillary blood,
v* = venous blood.
1.8
11
13.8
21
33
57
CAPILLARY-VENOUS DIFFERENCES IN BLOOD GLUCOSE
101
Capillary-venous blood glucose differences during the glucose tolerance test may be of
great magnitude especially during the peak.
In view of the fact that the two-dose, one-hour glucose tolerance test (Exton-Rose
procedure) 7 ' 8 involves a somewhat different physiological principle and presents the
organism with an additional stimulus, it seemed worthwhile to ascertain the magnitude of
the capillary-venous differences in blood glucose during this test. We were able to obtain
32 simultaneous capillary and venous blood sugar determinations during the course of
glucose tolerance tests on presumably normal individuals. As will be seen from the results,
a few of these individuals would appear to be diabetic. These tests were made after a
twelve hour fast—the blood was obtained from the finger and the vein simultaneously by
two different operators. Almost all of the determinations were made in duplicate, that is
two 0.1 c.c. quantities of blood were obtained from the finger and each was analyzed.
In the case of venous blood, the blood was placed in a test tube and before coagulation
could occur, two 0.1 c.c. quantities of blood were withdrawn and each was analyzed.
The analyses were carried out by the micro method of Folin and Malmros9, the results of
which were found to be satisfactory for our average range of blood sugar between 100 and
200 mg. per cent. For the most part the duplicates agree very well. Occasionally a divergence of 5 to 10 mg. per cent occurs. We feel that this is satisfactory for a micro method
employing visual colorimetry.
We used duplicate analyses to demonstrate that the capillary-venous differences which
we obtained were not dependant upon any technical errors but were true differences in
value.
The results of the Exton-Rose tests are set forth in table 2. It will be seen that, in general, the fasting blood glucose values are the same or nearly identical in both capillary and
venous blood. A divergence at one-half hour is marked in some cases and absent in a few.
At one hour the divergence is greater on the whole than at one-half hour and at times
extreme.
It is evident that one cannot predict the capillary-venous difference from either
the capillary blood sugar level or the venous blood sugar level alone. ExtonRose curves on capillary blood may be misleading when the results are not within
normal limits.
If the curve from capillary blood is normal, one may rest assured that the
venous curve will likewise be normal, but if the capillary curve is questionable
it is necessary to procure venous blood sugar values in order to obtain a true
picture of the glucose tolerance.
It is the habit of some to arrive at standards for interpreting capillary blood
by adding 10 or 20 mg. per cent to the values accepted as normal for venous
blood. Our results show that the use of such an average conversion figure might
well lead to error in the interpretation of certain individual curves, especially in
the case of the Exton-Rose procedure.
SUMMARY AND CONCLUSIONS
1. Large differences between capillary and venous blood glucose content
frequently occur during the one-hour, two-dose glucose tolerance test (ExtonRose procedure.)
2. These variable and unpredictable differences frequently render difficult
the interpretation of glucose tolerance curves when only capillary blood values
are obtainable.
102
PAUL H. LANGNER, J E . AND HARRY L. FIES
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terminations of arterial a n d venous
blood sugars in diabetics. Brit. J .
Exper. P a t h . , 8: 76, 1927.
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A.,
JOSLIN, E.
P.,
DUBLIN,
L. I., AND M A R K S , H . H . : Studies in
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(7) E X T O N , W. G., AND R O S E , A. R . : A new
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(8) M A T H E W S , M . W., M A G A T H , T . B . , AND
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Procedure). J . A. M . A., 113: 1531,
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(9) F O L I N , O., AND M A L M R O S , H . : An
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