Document 4agXjD0a1Zd4bx77E9rDMyg3R
IRVING GRAY, M. D., F.A.C.P. For t y-One east er n par kway
(ooPLBYPL&Za )
BROOKLYN, NEW YORK
^ arch 1 6 tb , 1936.
D r . Ro b e r t A. &ehoe, Un ive r sity o f Cin cin n a ti, Cin c in n a t i, Oh io .
ISy d e a r D r . Kahoe:
I would v e iy much a p p r e cia t e know ing what you
co n s id e r th e norm al amount o f le a d in 100 grams o f w hole b lo o d .
Se v e r a l ch e m ists around Hew Yo r k Cit y have t o ld me t h a t 0 .1 mgm. p e r 100 grams o f w hole b lo o d may be co n sid e r e d n o r m a l.
h e lp to me
lo u r o p in io n in t h is m a tte r w ould b e o f g r e a t
... With k in d e s t r e ga r d s and th a n kin g you fo r yo u r in t e r e s t , I rem ain
IG:HB
9Q
March 2 0 , 1936
Dr* Ir v in g Gr a y For ty-On e Ea ste r n Parkway Br o o k lyn , Tie Yor k
Dear Dr , Gr ays
You r le t t e r o f March l 6t h is n o t q u it e
so e a s y t o answer a s i t m igh t a p p e a r . Prom th e p u b lis h e d
in fo r m a t io n I am n o t co n vin ce d t h a t an y one can be e n t ir e ly
' sur e of t h e r ange o f v a r ia t io n o f the le a d In the blood o f
normal in d iv id u a ls . Prom our o b s e r va t io n s i t seems t h a t
th er e.! i s son co n s id e r a b le v a r ia t io n a t d iffe r e n t tim es
o f the day and u n d e r d iffe r e n t cir cu m s t a n ce s , 'He have
p u b lis h e d some fig u r e s w hich in d ic a t e t h a t th e mean va lu e
in the c ir c u la t o r y blood o f normal a d u lt s , a ls o o f normal
c h ild r e n , i s a p p r o xim a t e ly 0 ,0 5 m gs, p e r 100 e c* Vie h ave
seen v a lu e s a s low as *01 and ue h ave o c c a s io n a lly had
r e s u lt s on p r esu m ab ly n or m al p e r so n s a s h igh a s .l i j.. The
l a t t e r is q u it e r a r e , I b e lie v e , b u t w h ave no r e a s o n fo r
assum ing t h a t su ch va lu e s may n ot occu r in normal p e r so n s,
I s t i l l f e e l t h a t we have n o t co ve r e d d e fi n i t e ly t h e r an ge
o f v a r ia t io n and we have co n s id e r e d t h is a 3 a pr oblem w h ich
must b e com p leted s o o n , b u t u n fo r t u n a t e ly we have been so
busy w ith ou r selves
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ab le to s a t is fy b a sis o f our
p r esen t In fo r m a t io n , I sh ou ld say t h a t in terras o f a s in g le
o b s e r v a t io n , v a lu e s up t o 0.1 r ags, p er 100 ce must be r ega r d ed a s n o r m a l, v a lu e s betw een 0.1 and 0.15 s h o u ld be r e ga r d e d w it h some s u s p ic io n , and va lu e s above .15 sh ou ld p r o b a b ly be r e ga r d e d
a s a b n o r m a l. Prom a; s e r ie s o f o b s e r va t io n s made on In d iv id u a ls
I s h o u ld b e d is p o s e d t o r e ga r d p e r ce n t a ge v a lu e s above 0.1 as
evid en ce o f somewhat abnormal le a d exp osu r e.
I t must be ob viou s t o you t h a t I am sp e a kin g
In terms o f a n a ly t ic a l methods which have been c a r e fu lly s t a n d a r d ize d and w h ich a r e known t o y ie ld r e s u lt s w it h o n ly a m in u te e r r o r . So fa r as I know, th e o n ly two methods w h ich
a r e a v a ila b le t o giv e r e s u lt s o f t h is s o r t on s m a ll sam ples
o f blood a r e c a r e fu lly sta n d a r d ize d sp eetr ogr ap h lo methods and one or the oth er o f the c a r e fu lly checked m o d ifica t io n s o f the d it h ls o n e m ethod. Re su lts obtain ed by the le s s s e n s it iv e chem ical methods w ill f a l l in a d iffe r e n t zone and can n o t be r e la t e d to
the above va lu e s u n le ss the lo s s or e r r o r o f the method has been d e fi n i t e ly e s t a b lis h e d , and u n le s s i t i s known t o b e u n ifo r m . Ob viou sly in d e a lin g w ith v a r ia t io n s in a n a ly t ic a l r e s u lt s w ith in
t h e se l i m i t s , one must alw ays know th e p r e c is e method o f a n a ly s is em ployed.
Dr * Ir v in g Gr a y
I hope soon to be a b le to p u b lis h somewhat more p r e cis e in fo r m a t io n on t h is q u estloa w hich I r egar d as o f co n s id e r a b le im p or tan ce* Fo r t h e p r e s e n t , h ow ever , we r e ly more d e fin it e ly upon th e u r in a r y r e s u lt s th an upon th e b lo o d ,a lt h o u g h we a r e o b t a in in g d a t a on th e b lo o d fr om very ca s e w h ich comes t o o u r a t t e n t io n *
With k in d e s t p e r so n a l r e ga r d s ,
Sin ce r e ly yours,
R.A ~ Is
Ro b e r t A, Keh oe , M.D.
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