Bull. Environ. Contam. Toxicol. (1992) 49:504-508 9 1992 Springer-Verlag New York Inc.
nvieonrnm'cal C:~ir'~Zior, and Toxicology
iE
Stable Blood Cell Counts after One-Week Storage at Room Temperature Yukiyoshi Hirase, 1 Hirosei Makatsuka, 1 Toshio Kawai, 2 Shun'ichi Horiguchi, 2 and Masayuki Ikeda 3'4 1Sakai Biochemistry Laborato~, Sakai 591, Japan; 2Osaka Occupational Health Se~ice Center, Osaka 550, Japan, and 3Department of Public Health, Kyoto University Faculty of Medicine, Kyoto 606-01, Japan It is quite a r e g u l a r p r a c t i c e in c l i n i c a l medicine that b l o o d samples should be s u b j e c t e d to h e m a t o l o g i c a l examinations as soon after s a m p l i n g as possible and that the results should be e v a l u a t e d at the earliest convenience. W h e r e a s this is also true in o c c u p a t i o n a l and e n v i r o n m e n t a l m e d i c i n e in principle, the practice may be hindered by v a r i o u s study conditions. For example, it w o u l d be i n e v i t a b l e to spend more than a day for t r a n s p o r t a t i o n of the samples, in case the site of b l o o d s a m p l i n g is v e r y d i s t a n t from a h e m a t o l o g i c a l laboratory. The c r i t i c a l q u e s t i o n then is how stable the h e m a t o l o g i c a l p a r a m e t e r s are w h e n kept u n d e r what conditions. Despite remarkable progress in b l o o d conservation technique for t r a n s f u s i o n (Grode et al. 1985, Snyder et al. 1985), the q u e s t i o n s regarding stability of h e m a t o l o g i c a l findings generally remain unsolved, in contrast to serum b i o c h e m i s t r y for w h i c h effective storage conditions are more or less standardized (Gemba 1985, K a n n o 1989). The present examination was initiated to find answers to this p r a c t i c a l problem. MATERIALS
AND M E T H O D S
About 28 ml b l o o d samples were drawn from c u b i t a l vein of each of 20 h e a l t h y v o l u n t e e r s (15 men and 5 women at the ages of 20 to 39 years; Table i), and i m m e d i a t e l y divided into 2-ml p o r t i o n s in b l o o d sample containers [Vacutainer R from Becton Dickinson, Rutherford, NJ 07070, U.S.A.; 3 mg E D T A d i - p o t a s s i u m salt (Kanno 1989) is p r e s e n t in each container]. Seven samples out of 14 from e a c h p e r s o n (or 140 samples in total) w e r e kept at 4~ in a refrigerator, whereas r e m a i n i n g seven (or 140 in total) w e r e left at room temperature (i.e., about 20-25~ The r e f r i g e r a t e d samples w e r e kept at room temperature for 30 min b e f o r e s u b j e c t e d to the study. 4Correspondence/reprint
requests
504
to:
Prof.
M.
Ikeda
Table
i. H e m a t o l o g y
Parameter RBCcounts Hbconc. Ht values WBCcounts PLT counts
parameters
(Unit) (xl04 cells/mm 3) (g/100ml) ( % ) (100cells/mm3~ (xl0j cells/mm j)
of the samples
Mean
SD
CV(%)
477 15.1 44.2 64.9 24.1
43.8 1.76 4.73 19.84 5.06
9.2 11.7 10.7 31.5 21.0
at time
0
Min. -Max. 405 11.6 35.9 39.0 16.1
- 573 - 18.3 - 54.2 - 12.5 - 32.8
n=20
Five h e m a t o l o g i c a l p a r a m e t e r s of red b l o o d cell (RBC) counts, h e m o g l o b i n (Hb) c o n c e n t r a t i o n s , h e m a t o c r i t (Ht) values, white blood cell (WBC) counts and platelet (PLT) counts were studied taking advantage of an automated multiple hematological counter (Sysmex E3000, Toa M e d i c a l E l e c t r o n i c s , Kobe, Japan); RBC, WBC and PLT were counted by the electric resistance detection method, whereas Ht was m e a s u r e d a f t e r the theory that the p u l s e h e i g h t due to voltage changes (produced by the blood cells passing through an aperture of a d e t e c t i o n unit of the equipment) is proportional to cell v o l u m e (Toa M e d i c a l Electronics 1991. Hb was m e a s u r e d by the o x y h e m o g l o g i n m e t h o d at the w a v e l e n g t h of 535 nm. The samples stored e i t h e r in a r e f r i g e r a t o r or at room t e m p e r a t u r e w e r e s u b j e c t e d to the m e a s u r e m e n t s at 0 (i.e., immediately after blood sampling), 24, 48, 72, 96, 120 and 168 hours a f t e r i n i t i a t i o n of the s t o r a g e and the v a l u e s w e r e e x p r e s s e d in p e r c e n t taking 0-time v a l u e of e a c h s u b j e c t s as 100. Statistical differences in m e a n s were e x a m i n e d by ttest. The mean, SD and the m i n i m u m and the m a x i m u m of 0-time v a l u e s for the five p a r a m e t e r s are s u m m a r i z e d in Table I. Assuming normal distributions for the five measures, means of e a c h study items are shown as a f u n c t i o n of storage d u r a t i o n in Fig. I, together with standard deviations w h i c h are in some cases too small to be presented. There were no changes in RBC counts and Hb c o n c e n t r a t i o n s t h r o u g h o u t the study p e r i o d of 168 hours regardless of storage at r o o m t e m p e r a t u r e or in a refrigerator. In the case of Ht values, there was a g r a d u a l i n c r e a s e as a f u n c t i o n of s t o r a g e d u r a t i o n w h e n kept at r o o m temperature, and the i n c r e a s e was a l r e a d y statistically significant (p
110
9
. ..-~**
_** . f * . .
xT~
"I("
~
-""
100
__1
1051 PLT TT
T
~-T ~
IT
]-
48
96
120 144 168
95~ 0
24
72
TIME IN STORAGE (HOUR) Figure I. P o s s i b l e changes in h e m a t o l o g i c a l p a r a m e t e r s as a function of time in storage. Five h e m a t o l o g i c a l parameters of RBC (red blood cell) counts, Hb (hemoglobin) concentrations, Ht (hematocrit) values, WBC (white b l o o d cell) counts and p l a t e l e t (PLT) counts w e r e studied. Open and solid c i r c l e s show v a l u e s when stored at room t e m p e r a t u r e and at 4~ respectively. The r e l a t i v e changes w e r e c a l c u l a t e d taking i n d i v i d u a l 0-time values as 100(%). The symbols indicate arithmetic means and arrows s t a n d a r d d e v i a t i o n s of 20 determinations. In some instances, the v a r i a t i o n was too small to be shown in the figure. The asterisks i n d i c a t e s i g n i f i c a n t d i f f e r e n c e (** for p
nvieonrnm'cal C:~ir'~Zior, and Toxicology
iE
Stable Blood Cell Counts after One-Week Storage at Room Temperature Yukiyoshi Hirase, 1 Hirosei Makatsuka, 1 Toshio Kawai, 2 Shun'ichi Horiguchi, 2 and Masayuki Ikeda 3'4 1Sakai Biochemistry Laborato~, Sakai 591, Japan; 2Osaka Occupational Health Se~ice Center, Osaka 550, Japan, and 3Department of Public Health, Kyoto University Faculty of Medicine, Kyoto 606-01, Japan It is quite a r e g u l a r p r a c t i c e in c l i n i c a l medicine that b l o o d samples should be s u b j e c t e d to h e m a t o l o g i c a l examinations as soon after s a m p l i n g as possible and that the results should be e v a l u a t e d at the earliest convenience. W h e r e a s this is also true in o c c u p a t i o n a l and e n v i r o n m e n t a l m e d i c i n e in principle, the practice may be hindered by v a r i o u s study conditions. For example, it w o u l d be i n e v i t a b l e to spend more than a day for t r a n s p o r t a t i o n of the samples, in case the site of b l o o d s a m p l i n g is v e r y d i s t a n t from a h e m a t o l o g i c a l laboratory. The c r i t i c a l q u e s t i o n then is how stable the h e m a t o l o g i c a l p a r a m e t e r s are w h e n kept u n d e r what conditions. Despite remarkable progress in b l o o d conservation technique for t r a n s f u s i o n (Grode et al. 1985, Snyder et al. 1985), the q u e s t i o n s regarding stability of h e m a t o l o g i c a l findings generally remain unsolved, in contrast to serum b i o c h e m i s t r y for w h i c h effective storage conditions are more or less standardized (Gemba 1985, K a n n o 1989). The present examination was initiated to find answers to this p r a c t i c a l problem. MATERIALS
AND M E T H O D S
About 28 ml b l o o d samples were drawn from c u b i t a l vein of each of 20 h e a l t h y v o l u n t e e r s (15 men and 5 women at the ages of 20 to 39 years; Table i), and i m m e d i a t e l y divided into 2-ml p o r t i o n s in b l o o d sample containers [Vacutainer R from Becton Dickinson, Rutherford, NJ 07070, U.S.A.; 3 mg E D T A d i - p o t a s s i u m salt (Kanno 1989) is p r e s e n t in each container]. Seven samples out of 14 from e a c h p e r s o n (or 140 samples in total) w e r e kept at 4~ in a refrigerator, whereas r e m a i n i n g seven (or 140 in total) w e r e left at room temperature (i.e., about 20-25~ The r e f r i g e r a t e d samples w e r e kept at room temperature for 30 min b e f o r e s u b j e c t e d to the study. 4Correspondence/reprint
requests
504
to:
Prof.
M.
Ikeda
Table
i. H e m a t o l o g y
Parameter RBCcounts Hbconc. Ht values WBCcounts PLT counts
parameters
(Unit) (xl04 cells/mm 3) (g/100ml) ( % ) (100cells/mm3~ (xl0j cells/mm j)
of the samples
Mean
SD
CV(%)
477 15.1 44.2 64.9 24.1
43.8 1.76 4.73 19.84 5.06
9.2 11.7 10.7 31.5 21.0
at time
0
Min. -Max. 405 11.6 35.9 39.0 16.1
- 573 - 18.3 - 54.2 - 12.5 - 32.8
n=20
Five h e m a t o l o g i c a l p a r a m e t e r s of red b l o o d cell (RBC) counts, h e m o g l o b i n (Hb) c o n c e n t r a t i o n s , h e m a t o c r i t (Ht) values, white blood cell (WBC) counts and platelet (PLT) counts were studied taking advantage of an automated multiple hematological counter (Sysmex E3000, Toa M e d i c a l E l e c t r o n i c s , Kobe, Japan); RBC, WBC and PLT were counted by the electric resistance detection method, whereas Ht was m e a s u r e d a f t e r the theory that the p u l s e h e i g h t due to voltage changes (produced by the blood cells passing through an aperture of a d e t e c t i o n unit of the equipment) is proportional to cell v o l u m e (Toa M e d i c a l Electronics 1991. Hb was m e a s u r e d by the o x y h e m o g l o g i n m e t h o d at the w a v e l e n g t h of 535 nm. The samples stored e i t h e r in a r e f r i g e r a t o r or at room t e m p e r a t u r e w e r e s u b j e c t e d to the m e a s u r e m e n t s at 0 (i.e., immediately after blood sampling), 24, 48, 72, 96, 120 and 168 hours a f t e r i n i t i a t i o n of the s t o r a g e and the v a l u e s w e r e e x p r e s s e d in p e r c e n t taking 0-time v a l u e of e a c h s u b j e c t s as 100. Statistical differences in m e a n s were e x a m i n e d by ttest. The mean, SD and the m i n i m u m and the m a x i m u m of 0-time v a l u e s for the five p a r a m e t e r s are s u m m a r i z e d in Table I. Assuming normal distributions for the five measures, means of e a c h study items are shown as a f u n c t i o n of storage d u r a t i o n in Fig. I, together with standard deviations w h i c h are in some cases too small to be presented. There were no changes in RBC counts and Hb c o n c e n t r a t i o n s t h r o u g h o u t the study p e r i o d of 168 hours regardless of storage at r o o m t e m p e r a t u r e or in a refrigerator. In the case of Ht values, there was a g r a d u a l i n c r e a s e as a f u n c t i o n of s t o r a g e d u r a t i o n w h e n kept at r o o m temperature, and the i n c r e a s e was a l r e a d y statistically significant (p
110
9
. ..-~**
_** . f * . .
xT~
"I("
~
-""
100
__1
1051 PLT TT
T
~-T ~
IT
]-
48
96
120 144 168
95~ 0
24
72
TIME IN STORAGE (HOUR) Figure I. P o s s i b l e changes in h e m a t o l o g i c a l p a r a m e t e r s as a function of time in storage. Five h e m a t o l o g i c a l parameters of RBC (red blood cell) counts, Hb (hemoglobin) concentrations, Ht (hematocrit) values, WBC (white b l o o d cell) counts and p l a t e l e t (PLT) counts w e r e studied. Open and solid c i r c l e s show v a l u e s when stored at room t e m p e r a t u r e and at 4~ respectively. The r e l a t i v e changes w e r e c a l c u l a t e d taking i n d i v i d u a l 0-time values as 100(%). The symbols indicate arithmetic means and arrows s t a n d a r d d e v i a t i o n s of 20 determinations. In some instances, the v a r i a t i o n was too small to be shown in the figure. The asterisks i n d i c a t e s i g n i f i c a n t d i f f e r e n c e (** for p
