Page 1 of 1: half life of rbc

docsa · Credits: 9083 Preparing for: AIPGE My Scrapbook

whts the half life of rbc in stored bld??

if possible then reply with ref
thanx
docsa

hardcoremallu · Credits: 16608 Preparing for: General My Scrapbook

does half life means shelf life?
soory for this stupd question
i cant find specific half life of RBC

anyone with answers

docsa · Credits: 9083 Preparing for: AIPGE My Scrapbook

sorry 4 a very vague q.

to be more precise---
normal life of rbc = 120 days
whn stored bld is transfused n rbc r in circulation life = ???
i m confused b/w 90 n 60 days

n
shelf life that is when not transfused ?? if any bdy has evr cameacross value 4 this

Actionking · Credits: 1858 Preparing for: USMLE Step 1 My Scrapbook

Actionking · Credits: 1858 Preparing for: USMLE Step 1 My Scrapbook

In order to calculate the answer you should know the number of rbc's produced by human body in a day

docsa · Credits: 9083 Preparing for: AIPGE My Scrapbook

hi actionking
this q. is givn in one of the reputed dental mcq book
10-20 q. r directly picked frm this book
un4tun8tly this book has significant wrong ans.
they mention life of transfused rbc in circulation 90 days

but in NCERT BIOLOGY its mentioned = 60 days
n it appeared as the CBSE-PMT Q. this yr.

n i ve reffered few of med. books n i cudnt find any ref. thts y i m confused

docsa · Credits: 9083 Preparing for: AIPGE My Scrapbook

Actionking · Credits: 1858 Preparing for: USMLE Step 1 My Scrapbook

In humans let's assume that,

RBC production rate = RBC destruction rate R/day

Blood volume in a person V1/L
Blood volume taken from him/her for storage bag V2/L
Number of RBC in the human body=N
Totall amount of Rbc in the bag=n=N/V1 x V2

So, destruction rate of RBC in the bag=r
r=R/V1 x V2

Number of RBC in the bag
n/V1 x V2

Half amount of RBC in the bag n/2=N/2V1 x V2

T/ half = Half amount of RBC in the bag / r= R/V1 x V2

T/half = N/2V1 x V2 divided by R/V1 x V2

T/half = N/2 divided by R

T/half = N/2 x R

T/half = N / 2R

Now i hope you understand why production rate influences the T/half of RBC

docsa · Credits: 9083 Preparing for: AIPGE My Scrapbook

i got ans to this finaaly.. its 60 days .. within 50-60 days transfussed RBC is sequestered by spleen

grandmaster · Credits: 9246 Preparing for: AIIMS My Scrapbook

hi docsa
Firstly NCERT books are extremely reliable.So anything mentioned there is a straight answer
Secondly the concept of half life applies only to processes which :
1. progress in an exponential manner
2. the rate of progression is ALWAYS dependent upon the immediate number of participating particles
Since RBCs don't obey both of the above essential functions, the concept of half life doesn't aply to them

But of course half life applies t some other processes in the body for eg. Half life for gastric emptying is 30 minutes ( ref Laurence & Bennett pharmac )

reflectsme · Credits: 176 Preparing for: AIIMS My Scrapbook

inspite of what seems to be an ellaborate explaination (me being poor at math didnt go through it)
the conclusion or the hypothesis is seriously flawed
thalf of any drug whether adminstered bolus(transfusion) or even as a continuous infusion(haematopoiseis) does not depend either on the dose or the rate of inf; it depends on the metabolism and excretion the kinetics (first order or else ; zero order having no definite t half)
need exp refer katzung
i jhust remember the conclusions
by the way dose or rate influences one thing the steadystate conc and the duration of action
would be glad to hear from u

reflectsme · Credits: 176 Preparing for: AIIMS My Scrapbook

the answer of 60 days is easy to arrive at
in the packet of transfused blood if it were to be freshly collected would be destroyed in batches of 1/120every day
to be half they would need 60 days
BUT thers one catch all this assumes mechanical (non biological) precision
what of the damage that occurs during storage
what of the immune mechs (though the amount of hla expressed by the rbcs is less the wbc do good enough)
all this brings us to the probable answer of a maximum of 60 days
which would as a matter of statistics would not be anywhere close either t ot the mean median or the mode ina gaussian curve which most biologic systems seem to abide by when taken with a large sample
the botomline is
THE MAX HALFLIFE POSSIBLE( THEORETICALLY ) IS 60 BUT NOT IN ACTUALITY

dr_purkar · Credits: 208 Preparing for: AIIMS My Scrapbook

half life of normal rbc - 120 days
half life of transfused rbs - 60 days
half life of infant rbc - 100 days

srini23dr · Credits: 393 Preparing for: Karnatka PG My Scrapbook

Shelf life :its 45 to 60 days... cud remem da ref.

aungnyein · Credits: 581 Preparing for: MRCPath Part 1 My Scrapbook

In stored blood, RBCs have variable half live.Some are neocytes, some are aging or some are within normal life span.So, how do we know the half life of rbcs in stored blood?

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