Upsala J M e d Sci 88: 9-15, 1983 Cord Blood Platelet Aggregation; Quality Control by a Two-sample Technique G u n n a r Ahlsten, U w e Ewald a n d T o r s t e n T u v e m o From the Department of P a e d i a f r i t s , University Hospital, Uppsala, Sweden ABSTRACT T w o blood s a m p l e s w e r e t a k e n f r o m t h e c o r d s a t 17 n o r m a l d e l i v e r i e s 2-4 min a n d 5-8 min a f t e r b i r t h , r e s p e c t i v e l y . T h e d i f f e r e n c e in p l a t e l e t c o u n t b e t w e e n e a r l y a n d l a t e s a m p l e s in p l a t e l e t - r i c h p l a s m a w a s <5% i n n i n e c o r d s ( G r o u p A), a n d g r e a t e r in e i g h t c o r d s ( G r o u p 8). P l a t e l e t a g g r e g a t i o n s t u d i e s on t h e e a r l y a n d t h e l a t e blood s a m p l e s s h o w e d c o n s i s t e n t r e s u l t s w i t h i n e a c h c o r d in G r o u p A b u t n o t in G r o u p 8. T h e c o r r e l a t i o n s b e t w e e n t h e r e s p o n s e s w e r e high f o r G r o u p A. T h e a g g r e g a t i o n r e s p o n s e s w e r e a l s o s l i g h t l y b u t s i g n i f i c a n t l y h i g h e r in t h e l a t e s a m p l e s in t h i s g r o u p (p5%. T a b l e I . Platelet c o u n t in P R P of e a r l y a n d l a t e c o r d blood s a m p l e s . ( M e a n +SD) C o r d No. E a r l y s a m p l e s L a t e s a m p l e s D i f f e r e n c e / G r o u p e a r l y s a m p l e % I 2 3 4 5 6 7 8 9 10 I 1 12 13 14 15 16 17 890 440 850 I140 740 625 390 700 652 700 700 777 533 520 660 490 1035 885 380 840 960 740 660 475 750 659 670 680 77 1 479 525 740 365 995 - 0.6 - 13.6 - 1.2 - 15.8 + o 5.6 + 21.8 + 7.1 + 1.1 - 4.3 - 2.9 - 0.8 - 10.1 + 1.0 + 12.1 - 25.5 - 3.9 A B A 0 A B B B A A A A B A B 0 A T o t a l 697 5 2 0 1 681 5 187 G r o u p A (n=9) 763 5 149 752 A 140 G r o u p B (n=8) 622 2 235 601 5 2 1 0 P L A T E L E T AGGREGATION Q u a l i t a t i v e d e s c r i p t i o n E p i n e h r i n e (8.3 ug/l) p r o d u c e d n o v i s i b l e r e a c t i o n s (n = 8). C o l l a g e n 1.0 m g / l (n = 16) p r o d u c e d n o r e s p o n s e i n I 1 c o r d s a n d i r r e v e r s i b l e a g g r e g a t i o n i n one. In t h e r e m a i n i n g f o u r c o r d s r e v e r s i b l e a g g r e g a t i o n w a s o b t a i n e d . C o l l a g e n 5.5 mg/l (n = 12) c a u s e d r e v e r s i b l e a g g r e g a t i o n i n o n e case a n d i r r e v e r s i b l e 1 1 aggregation in I 1 cases. A D P 1.1 pmol/l (n = 15) produced reversible aggregation in 12 cases. In one cord no r e a c t i o n was seen. In t h e remaining t w o cords, both in Group B, reversible aggregation was noted in t h e e a r l y sample, while in t h e l a t e sample no significant aggregation was s e e n . A D P 3.3 v m o l / l (n = 17) produced reversible aggregation in 13 c o r d s and irreversible aggregation in four. T h e r e was no d i f f e r e n c e between t h e e a r l y and t h e l a t e s a m p l e with r e s p e c t to q u a l i t a t i v e responses t o any of t h e stimuli t e s t e d in Group A, while in Group B t h e r e was slight inconsistency f o r A D P 1.1 pmol/l. Q u a n t i t a t i v e results The number of s a m p l e s studied was sufficient for s t a t i s t i c a l evaluation in t h e case of A D P 1.1 and 3.3 u m o l / l and of collagen 5.5 mg/l. In Group A t h e e a r l y and t h e l a t e s a m p l e s from t h e s a m e cord showed very similar peak aggregation responses t o t h e s e stimuli (Fig.l), t h e k values (slopes) f o r t h e regression lines q u i t e c l o s e t o 1 (0.81-1.01) and c o r r e l a t i o n c o e f f i c i e n t s relatively high (r = 0.85-0.95). T h e r e was also a s t r o n g c o r r e l a t i o n between t h e e a r l y and l a t e samples with r e s p e c t to t h e lag phases in response t o collagen 5.5 mg/l (r = 0.99). Group A r = 0.85 25 %F, k = 1.02 ~ 0 0 25 50 AOD% 3 3,urnol/l 100 - 100 50 Group A . r = 0.89 k . 0 8 6 50 I " 0 - 0 50 100 AOD% 0 5 5 m g I i Group A r = 0.95 0 L 50 k = O 8 1 100 AODY. Early samples Relationship b e t w e e n maximal aggregation (AOD %) in e a r l y and l a t e blood samples in response to A D P 1.1 pmol/l, A D P 3.3 p m o l / l and collagen 5.5 mg/l. Group A (B) and Group B (0). The line r e p r e s e n t s t h e equation x = y. A s a l s o s e e n in Fig.1, t h e relations between t h e e a r l y and t h e late s a m p l e s w e r e less c o n s i s t e n t in Group B with k values varying from 0.59-2.25 and r = 0.53-0.98. T h e r e was a small but s y s t e m a t i c d i f f e r e n c e in t h e maximal AOD b e t w e e n t h e e a r l y and l a t e samples in Group A, with a significantly lower peak aggregation in t h e early s a m p l e f o r a l l t h r e e t e s t e d stimuli (Table 2, Fig.1). A similar significant d i f f e r e n c e , with a s h o r t e r l a g phase f o r t h e l a t e sample, was a l s o found in response to collagen 5.5 mg/l in Group A (pO.1 f o r a l l stimuli) (Table 2). 12 Table 2. Aggregation responses (AOD) t o ADP and collagen sign i f icant). (Mean +SD)(n.s. = non Stimuli Maximal aggregation @OD) early sample l a t e sample ADP 1.1 p m o l / l early sample l a t e sample A D P 3.3 p m o l / l early sample l a t e sample Collagen 5.5 m g / l T o t a l (n= 12) 14.9 54.5 p<0.02 18.055.3 (n=17) 38.921 6.0 n.s. 40.9217.6 (n= 12) 77.3515.0 n.s. 80.3217.8 Group A (n=8) 1 4.954.5 p