The deltoid intramuscular injection is easily accessible and is only for use with small volumes with a standard dose of 0.5ml and is never to go beyond 1.0ml. The deltoid muscle looks like and upside down teardrop with the muscle it-self being rather large. The actual injection site should be in the center of the muscle allowing for a small area on a large muscle to be the targeted area for the proper deltoid intramuscular injection site. This IM injection site is a little different to locate it requires finding the acromion process located on the scapula then measuring 2 to 3 finger widths in the middle of the arm is the location of the deltoid intramuscular injection site. The position that the patient is less important for the person, but much more important for the one giving the injection, being that it is more important that the healthcare professional is in a comfortable position. Of course, you want to make sure that whatever position the patient chooses, make sure that they are comfortable. With that being said the patient can be sitting, prone, supine, or lateral lying. The gauge of needle used can be a 23-25 with the length being 5/8-1.5 inches consideration must also be made for the size of the patient. Whether they are large or small will also determine the length of the needle. Once the injection site on the deltoid has been located make sure to inject at a 90 degree angle with a darting movement.
Diagram of deltoid intramuscular injection
Deltoid intramuscular injection
Deltoid Intramuscular injection- Considerations, Advantages, and Disadvantages
The deltoid intramuscular injection site is the preferred site to administer vaccines for infants that are older than 7 months and this is the only site where the Hepatitis B vaccine can be given. The advantages of the deltoid intramuscular injection is that as said before is easy accessible and patients are generally a lot more comfortable with exposing their arms as opposed to another body area. Unlike the ventrogluteal injection, a tourniquet can be applied if a hypersensitivity reaction occurs after a deltoid intramuscular injection. Disadvantages to this site are the size of the muscle mass is small in relation to other IM injection sites. The deltoid intramuscular injection is closely associated with nerves and vascular structures; this leaves a small margin for error with departure from the correct IM injection site. A deltoid intramuscular injection is not an apt site for repeated or large-volume injections exceeding 1.0ml.
Deltoid injections exceeding 3 ml cc
This was asked of me the other day "Are deltoid injections exceeding 3 ml cc ok?" Absolutely not, the only thing you might accomplish is causing severe pain in the patient with the volume you are trying to input into the patients arm.
How to administer a vaccine deltoid
With out further delay let's pretend that as a nurse you are about to give a vaccine for Hepatitis B. The first thing you do is wash your hands, dawn the gloves, grab a 24 gauge needle 5/8 inch will do. Draw up the amount of drug to be administered, locate the acromion process and measure down 2 finger widths in the middle of the arm then with a quick darting motion at a 90 degree angle, insert, aspirate to avoid blood stream injection, and inject.
Robert Intravia on March 24, 2018:
I've been taking 200 ml.of testosterone Intrmuscular cypiate injections for 6 yrs then 1.5 months ago my Dr.just took me off for no reason.I feel like. I'm going crasy and my wife and i are headed for divorce any week now.I don't know what to do,should i be having side effects or is it all in my mind.Miserable and sad
yaksa on June 19, 2017:
Where can I find some recommendation documents about the volume of medication is the critical factor in determining which site to use, as you say "The deltoid intramuscular injection is easily accessible and is only for use with small volumes with a standard dose of 0.5ml and is never to go beyond 1.0ml"
Levi (author) from New Mexico on July 19, 2015:
Into the muscle, pain at the most, but not death
Debbie on June 25, 2015:
Im an MA. Im sick with worry
Accidently injected .05ml of air intramuscular... What could happen?
Levi (author) from New Mexico on June 12, 2015:
@ jags no more than 1 ml should go into the Deltoid, otherwise you are more likely to have pain due to muscle damage.
Levi (author) from New Mexico on June 12, 2015:
@ cicudaf no more than 1 ml should go into the Deltoid, otherwise you are more likely to have pain due to muscle damage.
cicudaf on February 24, 2015:
I had a 4ml IM injection in my deltoid. The muscle is now EXTREMELY sore/inflamed, but not red. It looks otherwise normal. It does not hurt much, unless I use it. It also feels very tensed. I have been taking ibuprofen and using an anti-inflammatory cream, but the results are barely noticeable.
What could have caused this? Please reply asap.
Levi (author) from New Mexico on February 10, 2015:
Depends, normally B-12 should be given deep IM into the Ventrogluteal
lisa67 on January 29, 2015:
I had a 0.5ml B-12 shot in my deltoid today. My deltoid is very sore and it is painful when I raise my arm above my head or use the muscle. Should I be concerned or is there normal soreness after an injection of this amount in a small deltoid.
niel on May 24, 2014:
can i inject 4ml of anti hepa vaccine at deltoid site?
Michele on December 08, 2013:
I had a flu vaccine 6 weeks ago. I immediately had pain from the injection. It felt like a lot of pressure bringing tears. I went about my work(RN hospital) and after two weeks of pain and not being able to lift my arm above chest level or rotating outward I went to employee health. They did several days of Motrin then prednisone and finally MRI which showed bursitis edema in the muscle and a partial full thickness tear in the infraspinatus tendon. I am now going to see an orthopedic surgeon. Can an injection cause the tear.
sarah on November 15, 2013:
My younger sister is 17 and went in for a routine depo provera shot yesterday and she called me today tired and feeling sick like allergies/ upper resp inf ..she said she felt bad since yesterday after her shot ,she said the new male nurse was very nervous , kept pausing and measuring his hand on his deltoid muscle then her muscle , finally put the needle in super slow and injected it even slower when he removed the needle blood squirted out of her arm and bled more than she has ever bled before he asked her to compress it so he could clean the blood from the floor, he didn't get a doctor or tell anyone just covered it and had her compress over her jacket as she left ... what is this ?? I have never herd of such a thing ?
Levi (author) from New Mexico on July 05, 2013:
@healthnut I guess it is possible to hit superficial nerves. Make sure to rotate arms every month. But also give thought to the Ventrogluteal injection for long term use. This is due to the fact that it is a much bigger muscle.
healthnut123 on July 03, 2013:
I have given myself several b12 IM injections in the deltoid without any discomfort at all. However, as of late, even though I know I am hitting the correct area, it feels as though when the needle is about halfway in, I feel as though I am hitting a nerve. There is this weird feeling that somewhat mimicks an electric shock. Could it be that I am hitting a superficial nerve or something else? I know this thread is a little old, but I hope you get this as you seem very knowledgeable! Thank you!
zaty on January 21, 2013:
if use ndle 23 can??
lynn on September 19, 2012:
can an im given to high on arm cause neck pain for 2 weeks
Levi (author) from New Mexico on July 03, 2012:
Angle is 90 degrees, and size of needle depends on size of person's arm. Thanks!
harish on July 02, 2012:
plz notify the angle of needle inserted into deltoid while im injection doing.
Levi (author) from New Mexico on June 27, 2012:
Probably unrelated, sounds like a rotator cuff tear in your shoulder. You need an MRI to confirm.
nazr on June 26, 2012:
What happen if u got IM diclofenac sodium 2cc in deltoid 6 month earlier and now cannot raised arm above shoulder
Levi (author) from New Mexico on May 26, 2012:
@ Natasha - That may be, but the amount given here is for the healthcare professional, and a standard of practice nationwide.
Natasha on May 26, 2012:
Giving injections up to 3mL in the Deltoid is FINE. I have been giving myself 3mL B-12 shots which has never caused any problems at all.
Levi (author) from New Mexico on February 14, 2012:
Even still, an MA would require special training to give injections. Giving injections is not something you just do, you have to know the anatomy of the area you are injecting.....
April on February 13, 2012:
I am an MA, where I live ALL of the people that give shots are MA's NOT LPN's. You can not find a doctor here that does not have an MA that does injections and blood draws, and all of the MA's I've ever encountered have done a very good job of giving injections, so for the person that says that being that an MA gave the injection and that is the problem right there, that was not cool. Not all MA's do a bad job, only one every once in a while.
Levi (author) from New Mexico on February 07, 2012:
7 days is still not enough time for complete healing of an injection injury, keep working your arm, doing range of motion exercises, if the problem persist after a month from today, seek medical attention.
Levi (author) from New Mexico on February 07, 2012:
Yea go have the doctors look at it, I would say that the injury from the needle caused some type of scar tissue inside. Get it checked out, but no hurry.
ELIZABETH on February 06, 2012:
On Feb.1, 2012 I was given my 3rd Hep.B vaccine and my right deltoid is still hurting. I think she kind of angled the needle as she stuck me and when she pushed the vaccine it burned so much that it hurts for days. What should I do? My right deltoid feels like it's throbbing,burning, and still hurting. Help!
Mira on February 03, 2012:
Hi, I have had hepatitis B vaccine a year a go and my arm till now still swollen and itching me in the same area that I took the vaccine!! I feel like the medicine didn't go through my body and its still frozen in the same spot because its hard and I can feel it!!! what do think is that please!!! should i see a doctor asap!!!
kab on January 26, 2012:
What if tetanus is injected in the vein?
Levi (author) from New Mexico on January 20, 2012:
@ moe brass The injection you speak of is a joint injection, much different than what is spoken of in this article, But as far as the shoulder goes, some things are just unfixable, do you ever trying seeing a physical therapist?
moe brass on January 19, 2012:
had a injection on 12-23-09 to the back of my shoulder the first froze the shoulder first then the cordizone in the office of dr. when freeze wore off the pain was throgh the roof. before i could lift wieght over my head. after 12-23-09 could not lift over qa pound over my head lost a lot off movment in my right shouder . back in the dr office on 12-30-09 told the dr that my shoulder is worse from the shot he talk me to a notghter shot to the front off the shoulder and argude to ge a MRI did not what to do that at first he said that wormencomp would not pay i said i will go to another dr then he finialy agread to the MRI .. it showed proublems with shoulder . three surgery laiter still cant lift up weight over my head pain does not stop.
Levi (author) from New Mexico on January 18, 2012:
@ CindyEP I would really need to see a picture of the arm at least, and when you say "large amount of blood" where is it coming from, after injection? most swelling can be normal, but like I said, I would need to see it. If most cases, I have never heard of an MA giving an injection, most of the time you have to be at least an LPN, that could be enough right there, unless the MA had special training to do injections.
CindyEP on January 17, 2012:
I have a question. My 11yr-old daughter received a deltoid vaccine inj. and she immediately felt pain and she had a larger than normal amount of blood. only 1 day after her arm is huge and bruised and in a lot of pain. The MA that administered it was very uncaring and did not even do her proper preparing before the injection. It was a very unprofessional job. I am very worried could you please help me regarding complications, long-term damage to the muscle or nerves and if I have a base for lawsuit.
curious on December 14, 2011:
If a 2ml injection of B12 is given in the deltoid, how long after would it take to know if any damage is done? There was no pain or swelling to the area.
suraksha on November 18, 2011:
My 3 yr old son had an injection 2 months ago , immediately after receiving the injection he started limping . He has been in extreme pain recently and could not walk , he is always complaining that his leg were he got the injection is painfull . what should I do , we have run numerous test and everythings seems clear . I am very worried has he is only 3 .
Jane685101 on November 05, 2011:
Besides severe pain at the injection site, are there serious complications to injecting 1cc of lorazepam diluted with 5cc NS into a deltoid muscle? It wasn't a planned incident.
Levi (author) from New Mexico on November 02, 2011:
@ RN2B How much fuild came out, I would say that enough vaccine got into the muscle to absorb, and there is nothing the vaccine can do to the tissue above the muscle, so I would not worry about that. As far as a re-vaccine, consult with your MD.
RN2B on November 02, 2011:
I received a flu vaccine from an LPN who seemed nervous. I had clear fluid run out on my arm after the injection. I was wondering what could happen if the vaccine did not get into my muscle? Is it dangerous and should I get another vaccine?
Levi (author) from New Mexico on September 18, 2011:
@ muscan khan-- Not sure what you are trying to ask, but only inject into the deltoid, never just below or just above, exactly like the article says!!
muscan khan on September 17, 2011:
if i am inject im injacyion on diltaid musles ;in inject just crass below vane what agtion pation condition
Levi (author) from New Mexico on September 12, 2011:
@ Sanjay Chowdhry - Well, that does make it hard, but I would keep searching for a doctor who will say yes!!!
Sanjay Chowdhry on September 12, 2011:
Yes i did but doctors always advise me that the issue is not so big and i need to get in tch with physiotherapist .. which I did but still that problem is there .....
Levi (author) from New Mexico on September 04, 2011:
@ Sanjay Chowdhry - have you had it look at by a doctor, sounds like you may need surgery!!!
Sanjay Chowdhry on September 04, 2011:
I have some issue with my left shoulder ..I dont have any confidence as sometimes my left hand if i lift it jams as my bone is dislocated and it starts paining a lot and the hands remains stuck where it is .. and by lifting or giving a slight jerk it gets back to its original place but pains a lot .. I dont know what to do with it ...
Levi (author) from New Mexico on August 30, 2011:
@ ceendee never heard of injecting this drug before, why not just take it by mouth? Anyway, if in fact this drug is able to be given IM, the max in the deltoid is 1ml, any more than that, increases chances of muscle damage. Thanks :)
ceendee on August 30, 2011:
what will happen if 2 ml of paracetamol is injected at deltoid muscle? thanks.
Levi (author) from New Mexico on August 29, 2011:
@ Siren, sounds like the muscle may have been relaxing.
Siren on August 29, 2011:
I just have a quick question, I received the DTP vaccine yesterday, this morning while applying a warm compress to help with pain, I heard liquid rush around inside the muscle. Is this normal?
Levi (author) from New Mexico on August 24, 2011:
@ Clint, Recent changes to the way Phenergan is given don't even allow us to push the medication anymore or run it through a piggyback in veins @ the wrist and below due to the possibility of the vein blowing and causing that tissue damage. However, Phenergan was given IM all the time just a few years back. How many milliliters total were injected into the deltoid?
Levi (author) from New Mexico on August 24, 2011:
@ co Besides possibly hurting like heck, nothing!!
clint on August 24, 2011:
A friend came over and gave me a Phenagran injection into my L deltoid. It has been 11 days, I still have soreness as if I got the injection yesterday, and I also have superficial numbness. No brusing though. I found out this injection can cause tissue death. I am now terrified. Is it normal to be sore this long?
co on August 24, 2011:
so what happens if i njected 1.5 ml
lee22283 on August 07, 2011:
thank you for the answer. thats a great relief. have a good day!
Levi (author) from New Mexico on August 06, 2011:
@lee22283 I think you made the best decision. Whether it works you'll have to leave up to the body.
lee22283 on August 05, 2011:
also, my patient's left arm has a hemodialysis fistula and i cannot use the that arm if i must give 1 cc of hep b vaccine on each deltoid.
lee22283 on August 05, 2011:
my patient has ESRD and shes very thin. her hep b vaccine is double dosed (2ccs) she asked that i give her 1 shot only. so i gave the 2 ccs of hep b vaccine to her ventrogluteal region, risking the lower inmmune response rather than the muscle atrophy. what do you think will happen since it should only be given per deltoid?
Levi (author) from New Mexico on August 02, 2011:
The deltoid is a smaller muscle, I would recommend the ventrogluteal see my hub https://healthproadvice.com/procedures/Ventroglute Any soreness that you may feel at the moment, could be due to tensing up at the time of injection, be concerned if the pain isn't gone completely in 7 days. I would not use the deltoid for the long term. Nor more than once per month, or you will be sore for a long time.
T-test on August 01, 2011:
Just started testosterone injections for HRT and was advised by my health care provider to use the deltoid area. After injecting 1ml into the detoid with a 1" 22g needle I am experiencing soreness with movement of my arm, more so than any previous shot I have ever had. Is this a normal reaction to the testosterone injection, or did I inject too close to the acromium process?
Levi (author) from New Mexico on July 22, 2011:
maybe nothing, might not vaccinate properly, may also increase risk of side effects, wouldn't try it, unless you did, and if you're still alive, then you should be ok.
park on July 21, 2011:
i mean blood vessel?
park on July 21, 2011:
what will happen if you inject hepa b vaccine into the vein?
Levi (author) from New Mexico on July 09, 2011:
@ vivi2684 - Yes Nausea and vomiting is a normal side effect of Dilaudid, which is stronger than morphine. However, if she is still having Nausea and vomiting, then go back to the hospital, because it can also be related to the spinal injury, or some other disease process. Also, are her kidney's functioning well?
vivi2684 on July 08, 2011:
she was injected "Dilaudid". My mom is 53 years old.
Levi (author) from New Mexico on July 08, 2011:
@vivi2684 - Depends on what the medication was, what was it exactly, because the medication could still be in her system, also, how old is she?
vivi2684 on July 07, 2011:
Hello. My mother received a deltoid I.m injection 24 hours ago at th e.r because she was experiencing strong spinal pain since she is injured and has a hernia. Before the rn gave her the injection,she was given two chewable pills to avoid nausea for the shot. Well apparently that medication didn't do any good...she's been having nausea and vomitting ever since she was given the I.m injection which was 24 hrs ago...are these side-effects normal to last this long?? Thanks.
Levi (author) from New Mexico on June 28, 2011:
Im sure you could sue, make sure facts are straight. Like why you feel that way. Have you been disabled by this injection?
mary mc crudden on June 27, 2011:
can anurse get sued if im deltoid injection was given too high
Levi (author) from New Mexico on June 21, 2011:
@ madeeha- the swelling is the natural bodies reaction to being penetrated, the inflammatory process.
@ Kerry- It is possible that your daughter anticipated the poke of the needle and tightened her muscles up at the moment of injection, then after injection she tensed up more, causing her to feel the tightened muscles expand upon injection of vaccine. For the inflammation, try ice. Maybe even advise with a physician on a proper Motrin dose. Obviously if it doesn't start to clear up within a week or gets worse seek medical attention at your local ER.
kerry on June 21, 2011:
My daughter had her hpv vaccine in upper arm, this is the 3rd one of the lot, she has had no comps with the previous however this time she complained that when the needle went in she felt it "blow up" afterwards she felt a little unwell but put it down to nerves has it hurt more than before, she has now been left with a large lump at the site, a little red and quite warm in the area, is this something I should get checked out? I have put it down to nurse administering the inj wrong?? Can u advise thanks
madeeha on June 19, 2011:
can you tell me that the swelling is because of what??
jennakbbe on June 14, 2011:
I received a benadryl injection in my left arm 10 days ago, do to poison Ivy. At the sight of the injection, I have a huge lump, it is the size of a silver dollar, and is extremely sore. I feel it moving my arm around too, as it gives resistance against my range of motion. This is not normal, had the dr look at it, and i was laughed off. Could you let me know what could be the problem?
Levi (author) from New Mexico on June 09, 2011:
@ Aaisha it is headed to the blood stream anyway, hard to tell, if it hasn't already happened then nothing will.
@ B12, the person will be fine, just be careful in the future!
B12 on June 09, 2011:
Ok so I gave a B12 today, and accidentally gave them 1.0 cc rather than the 0.5cc... is this person going to be ok?
Aaisha on June 09, 2011:
what if Hepatits b vaccine is accidentally injected in a vein?
Levi (author) from New Mexico on May 28, 2011:
Use of 1 1/2 inch is not uncommon, use of one on the deltoid is, unless the person is very large, be careful with that size of needle.
CMA,CHP on May 28, 2011:
The use of a 1 1/2 inch needle isno t that uncommon I use them often for methylprednisone and hex
yusra on May 18, 2011:
wat r the complication of deloid injection if given at wrong site
erik on March 10, 2011:
i was injected tetanus toxoid vaccine on the right deltoid. did not actually look during injection procedure cause it only hurts me so i look away. at first, there was a stingy pain felt but the following morning, the pain turned sharply.
i palpated the injection site to be just below the acromion and is reddish and still painful when i exert effort on my arm during work.. I have put on ice-pack for almost a day now and still is painful....
what shall i do?
celine on January 10, 2011:
hi, i just want to ask, why should we avoid massaging the injection site? thanks..:)
Levi (author) from New Mexico on January 03, 2011:
@ Louise you have something else going on, visit a clinic or go to ER.
@ Mary the Axillary nerve is just below the Deltoid, but the fact that it radiates to your wrist tells me that you might have just slept on it wrong, but for the sake of assurance, visit a clinic or ER.
mary on January 03, 2011:
i received a B12 shot in my right deltoid today. i now have numbness going down the back of arm to my wrist. i assume this is temporary nerve damage? will it last long? anything i can do to help it?
Louise on December 26, 2010:
I had a flu shot in my deltoid over a month ago. I am still having pain in my deltoid so much so that it wakes me from sleep and I can't even put my arm over my head to get undressed. I went to occupational health at work because they are the ones who gave me the injection and I was told it was just a coincidence that the pain started the very same day as the flu shot and that I have rotator cuff tendinitis. I still feel they are related what are your thoughts
Levi (author) from New Mexico on December 17, 2010:
You can use the ventrogluteal site up to 4ml https://healthproadvice.com/procedures/Ventroglute
robert_k on December 17, 2010:
What should we use for doses larger than 1.0 ml?
Levi (author) from New Mexico on December 10, 2010:
@ LaurenAB warm compresses is the best advice however if it gets worse visit the ER
@kiozx most pain can be normal at an IM injection site. However, as stated numerous times before in this article if the pain persists or gets worse visit your ER
kiozx on December 10, 2010:
it is normal if there's a pain after im injection?anti hepa..
LaurenAB on December 08, 2010:
I got my third Gardasil vaccine (R deltoid) about 3 weeks ago, and about 1 day ago I developed a painful bump about the size of a pea at the injection site. The skin puncture from the injection is a tiny blue/purple mark... that is how I know the painful bump is exactly where the injection was given. The same day I received the Gardasil injection, I also received a Depo Provera injection in the other arm (L deltoid), both arms were sore for a day or two but the pain was not even bad enough to take an ibuprofen. There is no bump or blue/purple mark of the skin puncture at the site of the Depo injection. I had received these two injections on the same day 3 months prior to this last date without any problems. Additionally, that third Gardasil injection was more painful than any injection I've ever gotten in my life (including the 2 previous Gardasil injections, Depo Provera shots, allergy shots, Xolair shots, a corticosteroid shot). I am not sure if the new bump and pain has to do with the Gardasil itself or just the procedure that was done that day. I called the NP clinic I regularly see (where the injections were administered) and the nurse answering the phone said to put a warm compress on it. Any advice or thoughts? Thank you very much.
Levi (author) from New Mexico on December 01, 2010:
Not sure what you mean? Please explain a little more
Rose on November 29, 2010:
I got a pneumonia shot today at the local board of health. The nurse gave the shot even with the acromion process towards the back. My shoulder hurts tonight. Is that an acceptable site to be giving an injection?
Steroizi on November 20, 2010:
nice info :)
vivekc on November 18, 2010:
What happens if rabies vaccine is given intravascular route
kara on October 21, 2010:
Is it ok to give a flu shot deltoid IM with a 25 gauge 5/8" safety needle? I work at a clinic and that is our protocol unless the patient is obese, then we are to use our own judgement. Most of our flu shot patients are smaller, elderly individuals that don't have much muscle mass. Any advice?
Levi (author) from New Mexico on October 14, 2010:
It is like I always say "If you get a shot you are gonna get a knot." Unless the swelling continues to increase, you will be fine. Use warm compresses to relief some of the swelling. Thanks for the comment.
Sonny Puente MTASCP on October 14, 2010:
I GOT MY SERIES OF HEPATITIS B INJECTIONS AND NOW I HAVE A KNOT ON THE SIDE OF MY DELTOID MUSCLE. ANY IDEAS?
Levi (author) from New Mexico on October 05, 2010:
@ aftab please refer to the diagram in the shaded area on the deltoid and of course, please read....the info is all there.
aftab on October 05, 2010:
exact site for injection plz
Levi (author) from New Mexico on September 05, 2010:
It depends on a lot of factors, how many mls did you inject? I have only ever given this medication in the ventrogluteal site, https://healthproadvice.com/procedures/Ventroglute Also what gauge and size of needle did you use? Also, of course the patient bled, they got stuck with a needle, and a small knot is normal as long as it gets better not worse.
MA on September 01, 2010:
Today I gave a patient a depo provera injection, I located the site, injected, aspirated, no blood was noticed then pushed. Half way through the medication it got suck, the medication did not want to go in so I stopped and pulled out. The patient then bled a little and was left with a small knot in the injection site. What did I do wrong?
Levi (author) from New Mexico on August 26, 2010:
Discard the blood....not enough in the syringe to worry about saving.....your body will make more blood...thanks for the question. You should never re-use the needle to inject into correct spot....due to infection control. Draw up more solution in a brand new syringe and try the whole process again.
hanjie on August 26, 2010:
Im injection should be aspirated first right?....
to check if you hit the vein or not..
but what if...by the time you aspirate..and you hit the blood vessel...lets say just 0.05 cc of blood aspirated..mixed or unmixed...what would you do to the blood youved aspirated?...just push a little bit to removed the blood?..or will need to discard the sol'n inside the syringe and change a new one? or just inject the sol'n together with the blood on other site?