When acquisition blood native a boy for experimentation or study purposes, just how much is recommended and what have the right to be safely taken? Dr. Greene weighs in.

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Often blood from kids is drawn in the same big tubes offered for adults. Ns applaud parents, nurses, or phlebotomists acting as advocates for children when large-volume draws are ordered, to be certain that the amount requested is closely considered. In basic it is preferable to retract the smallest amount that will still allow the ideal medical treatment for the child. One means to carry out this is to ask the the blood be attracted in pediatric (not adult) tubes where possible, making use of something we speak to micro-sampling techniques – equipment designed to usage the smallest amount crucial for every test.

To parents, I imply asking come be sure it is truly important if someone argues taking more than 1 ml the blood per pound of your child’s load (or a best of 30 ml for larger children). Thirty ml is equivalent to 1 ounce.


I offered a general preeminence of ignorance I usage as an outside limit for blood draws, due to the fact that at this levels that blood loss there deserve to be measurable health and wellness consequences. Blood color etc in infants and also children have to not exceed 5% that their complete blood volume in any kind of 24 hour period, uneven medically necessary. This is a generous top limit. Ideally it should be less than 3% the the complete blood volume, and also where possible, micro-sampling approaches to minimize the amount additional are preferred. Blood color etc in infants and also children need to not exceed 10% of the full blood volume in any kind of one-month period, unless medically necessary.

The complete blood volume can be estimated from the age and also weight the the child. As a stormy estimate, because that pre-term babies, the amount of blood is around 90 ml every kilogram of human body weight. For term newborns, that is around 80 ml per kg. Because that older babies, 1 come 12 month of age, estimate 75 ml every kg. For toddlers, up to period 3 estimate 70 ml every kg. And also for larger children and also teens, 65 ml every kg is a reasonable estimate.

These are general guidelines, and also the individual medical case should be taken right into account. But think twice whenever adult approaches or devices are suggested for children.

To placed these numbers in perspective, I have attached the guidelines indigenous several various hospitals and labs. Together you will see, there is not universal commitment on the precise numbers, however there is a general awareness the it is ideal to minimization blood loss, and also the numbers provided at various centers loss within a small range.

Alliance laboratory Services offers the adhering to table:

Maximum amounts of Blood come be drawn From patient Younger than 14 Years

Patient’s Weight PoundsPatient’s Weight Kilograms (approx.)Maximum Amount come be attracted at any kind of one time (mL)Maximum amount –cumulative come be attracted during a offered hospital continue to be (1 month or less-mL)


At harvard Mass basic they usage the adhering to guidelines for study purposes:

Blood volume taken from children must be much less than 3 cc/kg body weight per 8 mainly period. In researches where the direct advantage far outweighs this volume restriction, a full protocol should be it is registered for review of the full committee, and also the adhering to guidelines will apply:If more than 3 cc/kg body weight per 8 week period is required and justified by the potential benefits, as much as 9 cc venous blood/kg body weight/8 week duration may be thought about in older youngsters (e.g., not neonates, toddlers, etc.), v the latter number being the absolute upper limit.

The indict of the NIH Clinical center for research functions are:

For pediatric patients, no more than 3 ml/kg. May be taken for research objectives in a solitary draw, and no much more than 7 ml./kg. Might be attracted over any type of six-week period. Investigators should think about further limiting blood drawing in patients v anemia or short cardiac output.

In instances of clinical needs, phlebotomy in excess of the over limits may be permitted.

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At UCLA they use:

No an ext than 2.5% of complete blood volume might be attracted solely for research objectives (no benefit to the subject) within a 24-hour period. This is usually 2 ml/kg.No much more than 5% of total blood volume might be drawn solely for research purposes (no advantage to the subject) within a 30-day period. This is normally 4 ml/kg.If the investigator request blood in overabundance of this amount, he/she must administer a detailed justification for this, and also describe what safeguards space in location to protect the subject from undue risk.