Document KG9Y2xgyjxKMYjp6QrRR5Bdq0

September 19 19U9 Dr. Pudolph'F. '"aldman bureau of Industrial hygiene 117 '.'aIn S t r e e t Hartford, Connecticut D e a r D o c t o r 'Valcrnan: < v our letter7 o e September has raised a question which I feel requires some considerable discussion. I should not want to criticize severely the procedure o* L e v i n e and ^ahy, as de s c r i b e d in their a r t i c l e in the Journal of Industrial hygiene and Toxicology. Actually, I s &'{ the a r t i e ' e b e f o r e its p u b l i c a t i o n and a p p r o v e d it, although I had some misgivings, since fully justified, concern ing the- a p p l i c a t i o n w hich would be mac e of t h e i r procedure. Actually., one should never, under any circumstances, attempt to int e r p r e t the lea d e x p o s u r e and a b s o r p t i o n of an i ndividual o-. the b asis of an a n a l y t i c a l result on w e sample o D urine. No 1a r m o r of a p p l y i n g a c o r r e c t i o n f a c t o r or a ny o t h e r mathfSiatical expression, can ever m a k e such a result s a t i s f a c t o r y The concentration of lead in the urine varies from hour to ho u r end fron day to uay in response to a number of factors, some of w h i c h are unknown. It is true that the l a r g e s t physiologies? factor that we h a v e been able to put our fing e r on is that of .the volume of w a t e r voided .within a unit of tine. There are other factors w h i c h contribute to this, however, w h i c h m a k e it u n s a f e to r ely u pon anv c a l c u l a t i o n base:! or s p e cific g r a v i t y or any o t h e r k n o w n factor. T h e r e f o r e it is n e c e s s a r y to have a n u m b e r of small samp l e s oP urine, or one or m o r e s a m p l e s of l a r g e volume, or a s air.ple or samp l e s of blood, in arriving at the physiological status of the individual with respect to the current rate of lead excretion. In our practice, we require samples of blood with spot samples of urine in arriving at a conclusion. I would never express an opinion on less than one samle of urine in association with a sample of blood taken at the same time. Frequently the results are in agreement on these two materials, and under these c onditions, i n t e r p r e t a t i o n can o f t e n be made. F.ven here, however, both results m a y be in that dang e r ous zone o^ * interne<i/&tQ^ <( ^ Q0 it ( o t t D r. F.K . Waldman Page 2 magnitude which makes interpretst'on difficult, and under these conditions we alwavs require additional samples before arriv ing at an interpretation. Under certain circumstances we require the collection of samples of urine of large volume. It is obvious that 2)i-hour samples cannot be c o l l e ct e d u n d e r cer t a i n conditions. The alte r n a t i v e is to collect samples of large volume during periods in which the individual is not at w o r k and while he is clean and free of the likelihood of contaminacin. This can often be done quite satisfactorily, as our e x p e r i e n c e o ver m a n y y e a r s has d e m o nstrated. I encl o s e herewith the kind of instructions we issue for the collection of various samples. Then any part of this procedure is left to the w o r k e r or to a patient, we s u p p l e m e n t the r e g u l a r instructions with carefully worded advice. Under these con ditions we usually get reliable samples. \'! e have b e e n m e a s u r i n g the s p e c i f i c g r a v i t y o u r s e l v e s for a n u m b e r of nears, and we have s a t i s f i e d ourselves, as you appear to have done, that this observation cannot be used e x c e p t to make a r o u g h est rate of the s i q n i f i e s n e e of the dilution factor. The p r i m a r y value c,p coll ectinr*. one sample of u rine from each of a aeries o* err.ployese wh o arc engs rod in the same wort- , lies in the fact that ver lability car be d e a l t with ms tvyra tic a l l y , arc that the group as a whole car be a u p r a i s e d f a i r l y satis b-c toi-J.lv. Indeed, p r e c i s e l y the same kind of var a oil ity will be found if one obtains a c o r r e s p o n d i n g n u m b e r of samples at d i f f e r e n t times fro m the ssrre Individual. Thus, wo use a number- cf analyses, whether on an Individual or on a series of indi victuals, as a m oans of interpret! nn the severity of the lead exposure of a fairly uni f o r m group of men. This is the only m a n n e r in w h i c h such analyses can be used in a trustworthy fashion. On the other hand, if you are trying- to l earn the status of an individual , y o u v/ill have to analyse a series of samples, or else y o u w i l l hove to obtain both blood and urine at the same time. The blood does not show the h i g h v a r i a b i l i t y that is f o u n d in the urine, and therefore, if one is to analyze only one material, he should by all means employ the olood. Unfortunately, the range of vari a b i l i t y in the b l o o d is r e l a t i v e l y small, in r e l a t i o n to various d e g r e e s o*' lead absorption, and therefore, o n e 's i n t e r p r e t a t i o n is b e t t e r if he h a s the r e s u l t s of the analyses of both blood and urine. K EiJ r--' A V ' |Hr > !, Uu U o D r.. F. K. vVel dman Pap-e 3 I trust that I have made my position clear on thi matter. The p r o b l e m is not an easy one, and u n f o r t u n a elv, in the practical performance of the day's work, we are of ton put to the n e c e s s i t y of doinrr loss than that w h i c h is required to yield sound and adequate information. Sincerely yours, R o b e r t A. Kehoe, // // / /MMISSIONER OF HEALTH y l A H l E r H . O S B O R N , U . D .. O. P . H. B u r e a u o f I n d u s t r ia l H y g ie n e 1179 M A IN ST R E ET A L B E R T S . G R A Y . 31. D . D IR EC TO R ALLAN L. COLEMAN. B. S. C H IEF IN D U ST R IA L H Y G IEN IST STATE OF CONNKCTICI'T DKPARMENT OF HEALTH HARTFORD, 1 1 September 8, 1949 Bobert E* Kehoe, M* D* Director Kettering Laboratory of Applied Physiology College of Medicine University of Cincinnati Cincinnati, Ohio Dear Doctor Kehoet Our Department of Industrial Hygiene is concerned with the examination of body fluids from lead exposed workers* Because we very often notice that the speoific gravity of the urines, especially of spot samples, varies considerably, we are using a correction factor according to the article "Evaluation of Urinary Lead Determinations" by Leo Levine and John P* Fahy, Division of Occupational Hygiene, Massachusetts Department of Labor and Industries, Boston, Massachusetts, which appeared in the Journal of Industrial Hygiene and Toxioology, Volume 27, January* Deo ember 1945, pages 217-223. I am writing to ask your opinion on this matter as I know that you have had extensive experience in evaluating lead findings* It seems to me that the use of the correction factor according to spe cific gravity is justified only within certain limits, that is, so long as the speoific gravity does not deviate too far from the average speoific gravity (approximately 1*C16 to 1*034)* Extreme high or low speoific gravities should be handled with precaution* In our steady control of industrial workers, we use the following pro cedure of sample taking! It is very difficult to obtain 24-hour specimens, therefore we distribute lead-free bottles to the workers which are used by them for voiding early morning urine at home* This pre caution is taken in order to prevent any contamination with lead from work olothes or other sources in the factories* With only a few exceptions, the specific gravity of these urines does not vary much from the mean specific gravity* However, we also receive samples from doctors with private patients who are suspeoted of lead poisoning and it happens very often that speoiflo gravity values of these urines are in the far extremes* N 7957.01 / Robert E* Rehoe M D - 2- September 8 1949 / W e had, for instance, the following oases of suspected lead poi- sonings t ' Speoifio Adjusted Lead Finding Gravity Lead (1) 0*086 m g * A * urine (2) 0*065 m g * A * urine (3) 0*130 m g * A * urine 1*004 1*002 1*002 0*516 mg* 0*760 mg* 1*560 mg* Not one of these three patients showed any severe symptoms of lead poisoning whereas we found many oases where lead content ranging from 0.16 to 0*40 showed marked beginning plumbism* W e will appreciate your comments on this matter which we would find very valuable from a man of your experience and ability* Very truly yours RKHfjrrp Rudolph R* Waldman, Ph*B* Principal Biochemist Kf 0007581