Hemoglobin test





Definition

Hemoglobin is a protein inside red blood cells that carries oxygen. A hemoglobin test reveals how much hemoglobin is in a person's blood. This information can be used to help physician's diagnose and monitor anemia (a low hemoglobin level) and polycythemia vera (a high hemoglobin level).


Purpose

A hemoglobin test is performed to determine the amount of hemoglobin in a person's red blood cells (RBCs). This is important because the amount of oxygen available to tissues depends upon how much oxygen is in the RBCs, and local perfusion of the tissues. Without sufficient hemoglobin, the tissues lack oxygen and the heart and lungs must work harder to compensate.

A low hemoglobin measurement usually means the person has anemia. Anemia results from a decrease in the number, size, or function of RBCs. Common causes include excessive bleeding, a deficiency of iron, vitamin B 12 , or folic acid, destruction of red cells by antibodies or mechanical trauma, and structurally abnormal hemoglobin. Hemoglobin levels are also decreased due to cancer, kidney diseases, other chronic diseases, and excessive IV fluids. An elevated hemoglobin may be caused by dehydration (decreased water), hypoxia (decreased oxygen), or polycythemia vera. Hypoxia may result from high altitudes, smoking, chronic obstructive lung diseases (such as emphysema), and congestive heart failure. Hemoglobin levels are also used to determine if a person needs a blood transfusion . Usually a person's hemoglobin must be below 7–8 g/dL before a transfusion is considered, or higher if the person has heart or lung disease. The hemoglobin concentration is also used to determine how many units of packed red blood cells should be transfused. A common rule of thumb is that each unit of red cells should increase the hemoglobin by approximately 1.0–1.5 g/dL.


Precautions

Fluid volume in the blood affects hemoglobin values. Accordingly, the blood sample should not be taken from an arm receiving IV fluid. It should also be noted that pregnant women and people with cirrhosis, a type of permanent liver disease, have extra fluid, which dilutes the blood, decreasing the hemoglobin. Dehydration, a decreased amount of water in the body, concentrates the blood, which may cause an increased hemoglobin result.

Certain drugs such as antibiotics , aspirin , antineo-plastic drugs, doxapram, indomethacin, sulfonamides , primaquine, rifampin, and trimethadione, may also decrease the hemoglobin level.

A nurse or phlebotomist usually collects the sample by inserting a needle into a vein, or venipuncture, after cleaning the skin, which helps prevent infections.


Description

Hemoglobin is a complex protein composed of four subunits. Each subunit consists of a protein, or polypeptide chain, that enfolds a heme group. Each heme contains iron (Fe 2+ ) that can bind a molecule of oxygen. The iron gives blood its red color. After the first year of life, 95-97% of the hemoglobin molecules contain two pairs of polypeptide chains designated alpha and beta. This form of hemoglobin is called hemoglobin A.

Hemoglobin is most commonly measured in whole blood. Hemoglobin measurement is most often performed as part of a complete blood count (CBC), a test that includes counts of the red blood cells, white blood cells, and platelets (thrombocytes).

Some people inherit hemoglobin with an abnormal structure. The abnormal hemoglobin results from a point mutation in one or both genes that code for the alpha or beta polypeptide chains. Examples of hemoglobin abnormalities resulting from a single amino acid substitution in the beta chain are sickle cell and hemoglobin C disease. Most abnormal hemoglobin molecules can be detected by hemoglobin electrophoresis, which separates hemoglobin molecules that have different electrical charges.


Preparation

No special preparation is required other than cleaning and disinfecting the skin at the puncture site. Blood is collected in a tube by venipuncture. The tube has an anticoagulant in it so that the blood does not clot in the tube, and so that the blood will remain a liquid.

Aftercare

Discomfort or bruising may occur at the puncture site. Pressure to the puncture site until the bleeding stops reduces bruising; warm packs relieve discomfort. Some people feel dizzy or faint after blood has been drawn, and lying down and relaxing for awhile is helpful for these people.



Risks

Other than potential bruising at the puncture site, and/or dizziness, there are usually no complications associated with this test.



Normal results

Normal values vary with age and sex, with women generally having lower hemoglobin values than men. Normal results for men range from 13–18 g/dL. For women the normal range is 12–16 g/dL. Critical limits (panic values) for both males and females are below 5.0 g/dL or above 20.0 g/dL.

A low hemoglobin value usually indicates the person has anemia. Different tests are done to discover the cause and type of anemia. Dangerously low hemoglobin levels put a person at risk of a heart attack, congestive heart failure, or stroke. A high hemoglobin value indicates the body may be making too many red blood cells. Other tests are performed to differentiate the cause of the abnormal hemoblogin level. Laboratory scientists perform hemoglobin tests using automated laboratory equipment. Critically high or low levels should be immediately called to the attention of the patient's doctor.

Resources

BOOKS

Chernecky, Cynthia C. and Barbara J. Berger. Laboratory Tests and Diagnostic Procedures. 3rd ed. Philadelphia: W. B. Saunders Company, 2001.

Kee, Joyce LeFever. Handbook of Laboratory and Diagnostic Tests. 4th ed. Upper Saddle River, NJ: Prentice Hall, 2001.

Kjeldsberg, Carl R. Practical Diagnosis of Hematologic Disorders. 3rd ed. Chicago: ASCP Press, 2000.

ORGANIZATIONS

American Association of Blood Banks. 8101 Glenbrook Road, Bethesda, Maryland 20814. (301) 907-6977. Fax: (301) 907-6895. http://www.aabb.org .

OTHER

Uthman, Ed. Blood Cells and the CBC. 2000 [cited February 17, 2003]. http://web2.iadfw.net/uthman/blood_cells.html .


Victoria E. DeMoranville
Mark A. Best, M.D.

User Contributions:

shivani
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Nov 1, 2007 @ 11:11 am
ITS REALLY A NICE PAGE TO READ.
I READ MANY PAGES BEFORE IT BUT I COULDN'T FIND SUCH ACCURATE INFORMATION
sks
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Aug 29, 2009 @ 8:08 am
This page had been a big help. Laid out simply and clearly. I don't need to search any more pages. Thank you.
GC
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Nov 8, 2009 @ 4:16 pm
straightforward and helpful
I needed to know whether my hemoglobin was normal and now I do.
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Apr 8, 2010 @ 9:21 pm
Excellent information- answered all questions in a clear and easy to understand manner!
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Apr 9, 2010 @ 4:04 am
I wish the other sites answer queries the way it has been done here.So clearly and entirely the query has been answered.It was very interesting also.Thanks n keep it up.
Jill L
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May 23, 2010 @ 5:17 pm
Very helpful. I was hospitalized for low hemoglobin levels--7.4 at the doctor's office, 6.2 in the hospital--and received a transfusion. I knew what was normal but wanted to know what was dangerously low. I searched online for some time before I found your article. It was clear, concise, and informative. Thanks.
Puneet
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May 31, 2010 @ 4:04 am
yes really yhis page has been a great help but i want to know for children too.
Anne
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Jun 20, 2010 @ 12:00 am
How can you tell if low hemoglobin is due to taking antibiotics??
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Jul 16, 2010 @ 7:07 am
Am a man and my hemoglobin is 18.9 what can I do to bring it to the normal rate?
is there anything I can eat or reduce to eat for those results?
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Sep 5, 2010 @ 11:23 pm
I'm a women around 24 years old. 3 years before, I've test my RBH which is I get around 8.0 and now it was about 10. But still I've to worry about it. What would it be if I'm pregnant someday. What risk that I have to face and how to prevent it?
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Oct 21, 2010 @ 10:22 pm
i reallly like the information i got here it outlined the things that i was looking for ..i just want to find out is the hemoglobin mesuared the same in the world..is 90 low for a male cancer patient going through chemotherapy at the moment
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Oct 26, 2010 @ 3:03 am
The clearest explanation Ive found, related to low hemoglobin. No need to read any further articles- thank goodness. Wish Id found this one first and saved a tonne of time :) Thank you.
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Oct 29, 2010 @ 11:11 am
if the amount of hemoglobin is 6.8 what diseases causes man?and the age of man is 14years
Graham McLeod
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Dec 6, 2010 @ 11:11 am
My daughter has chronic renal failure and we are battling with anemia. This has clarified some issues for me. Thanks.
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Dec 10, 2010 @ 1:13 pm
I have to write an assay to university , you do agreat job .thanks alot.
Jeannine
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Feb 6, 2011 @ 8:08 am
I am helping a friend to understand the risks low hemoglobine since her brother has cancer. He has had very low hemoglobin (5.7) and it was raised to 1.0 in few days. This was very helpful. As noted before, it is a small summary however very educational. Thanks.
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Apr 4, 2011 @ 4:16 pm
it really helped me because i could clearly understand what Hb was all about. It heped me in my studies.Thanks alot
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May 2, 2011 @ 12:12 pm
i wish all laboratory tests and significances and all blood test
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May 3, 2011 @ 5:17 pm
Good morning,
I am have got Haemoglobin 85% test from last week and iron is very low 6/12. I has Anemia on and off for over 13-15 years. Sometime my breathing lung went different to breath went on and off - why? Which one do I have low or high Haemoglobin from 85%?
My GP is very worries and I have to urgent appointment to hosptial soon. I am still waitng for appointment? Why waiting so long? is that still okay? Do Haemoglobin need out of human's blood and put health blood transfusion into human body? Where do they sticks in the vein on arm or on body? How long do you think I will stay in hosptial for how many days or just one day? because I need arrange to looking after my little children. Anne Wyrill
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May 5, 2011 @ 1:13 pm
I am a 40 year old female recently had a blood level of 5.7. I had a blood transfusion and this is my third one. I have a job but no insurance and three daughters to care for. When I go into the hospital they give the transfusion and send my home due to financial. I relly need help I feel sick and weak daily I'm tired alot. WHo can and will help me please. I want to live
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Jun 8, 2011 @ 2:14 pm
My 3 year old son had his tested at his 3 year old well visit today and his level was 15 or slightly higher. His pediatrician said that this is one of the highest he's seen and it was most likely due to good nutrition. I am somewhat concerned however, as while my son eats some vegetables he does not eat a lot of leafy greens or red meat. He does however, eat a lot of oatmeal and eggs. Is this considered normal, or should I get a second opinion?
claire
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Jul 26, 2011 @ 7:07 am
I am 44yrs old female, I have been feeling very tired on and off and body feeling heavy, also excessive bloatedness on and off, my doctor had done several tests and I have had a hemoglobin bloodtest result of 5.7, what does this mean please? Thankyou Claire x does this need attention x
maltii
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Sep 1, 2011 @ 2:14 pm
my son is 2 years old.his hb is 7.4 grams.last month it was 8.7.i am worried what to do.what are the risks.
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Sep 17, 2011 @ 5:05 am
the article seems very interesting. I was happy to know about low levels and now I am confident when to go for blood transfusion.
ali
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Dec 15, 2011 @ 12:12 pm
why females have less amount of blood in competition to adult male ? please answer me if you know ? thank you
Halima
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Dec 21, 2011 @ 8:20 pm
It is a very good article to read. It is self explanatory and educative. I am a woman of 47years old, I have fibrious and bleeds heavily each month. My blood tested that I have low hemoglobin and suffering from aenamia. I have used iron tablets to help me increase my hemoglobin level but no good effect. What is the right solution as I do not want blood transfusion.
anitha
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Jan 2, 2012 @ 12:00 am
Hi,my sister(19 yrs) has haemoglobin count of 6.4 hp.She falls sick often.but,she won't look tired.she is very energetic.she hadn't done any blood transfusion.Should it neccessary for her to take blood tranfusion? how can she improve her hp count? guide me pls.
R.ARNOLD
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Feb 3, 2012 @ 8:08 am
WILL BORDERLINE TRANSFUSION PATIENTS (8.0-8.5GM/DL)BE LIKLY TO EXIBIT DIFFERENT HGB. VALUES BETWEEN SAMPLE DRAWEN AT 5:00 AM & 11:00AM?
ronky
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Feb 10, 2012 @ 5:17 pm
i'm relieved having read the article and i'm happy there's room for questioning
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Mar 3, 2012 @ 10:10 am
I was admitted into the hospital with pluracy and pneumonia that would not go away and after 2 days there the hospital staff came in telling me that my hemoglobin was 4.7 and I needed a transfusion. It was a few days later and I needed another one. They found out that I have Lupus and Vasculitis, both autoamune diseases. I am better now but I am on alt of medication. If you have the same medical conditions that I have, get your blood tested often and get the pneumonia vaccination every 5 years.
Ofir
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Mar 23, 2012 @ 3:15 pm
I am a 40 years old man and my hemoglobin is 18.9 what can I do to bring it to the normal rate?
is there anything I can eat or reduce to eat for those results?

is it indecate on a sicknes?
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May 11, 2012 @ 1:13 pm
About 5 weeks ago whilst out walking long distance, I started becoming out of breath and my skin turned yellow. I became weaker and weaker til I could hardly stand up. Being a sporty type I was shocked and had no idea what was wrong with me. I made a very rare visit to see my doctor, who immediately upon seeing me, told me that I was severely anemic. She arranged a for a blood test, and within hours she phoned to tell me that my reading of Hb 6.0 was dangerously low, and that I should go straight to the hospital. So I spent 4 days in the hospital last week, where they gave me 4 blood transfusions, and did many tests, but they are not able to tell me how my readings were so low, and why I had seemingly lost so much blood over a long period of time. My impression was that if your body is healthy then any blood loss over time would be re-generated automicatically withou one necesarily becoming anemic. I am very concerned to understand how I could have had such a low reading with no apparent internal bleeding? Any advise is appreciated. I normally opt for natural herbs, vitamins and lots of exercise and fresh air. I am 59 years old.
Any info and advise is appreciated. As it is still a big mystery to me as I normally go cycling, climbing, do weight training, swimming etc?
yara
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Jun 26, 2012 @ 12:00 am
can drug abuse decrease the hemoglobin levels? and what are these drugs?
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Jul 11, 2012 @ 5:05 am
My 6 months pregnant wife has haemoglbin of 9g/100ml.What can she do? she is worried.
SistaDe
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Sep 2, 2012 @ 8:08 am
My 15 year old son who is an outstanding athlete and works out hours daily, recently had a routine physical which showed a high hemoglobin 20 and then were sent to a Hematologist. This week, my 15 YEAR OLD with a high HEMOGLOBIN 20 and a high HEMATOCRIT 55.8 saw the hematologist and HIS LIFE is literarily on hold! What in the world has happened or caused such a thing to happen? We are scared out of our mind as we read things on the internet! He is receiving blood therapy twice a week; 500 ml of blood removed and then hydrated with saline. The doctor has sent his blood to Mayo clinic and we have every test and doctor lined up over the next two weeks. All his paper work states is "secondary POLYCYTHEMIA, etiology to be determined". The only symptoms my son has had in the past 6 months is asthma, fatigue, dizzy and extra perspiration, however none were abnormally striking! Any knowledge would be greatly appreciated... we are desperate for any insight!
UMASHANKAR KUSHWAH
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Oct 23, 2012 @ 10:10 am
I LIKE THIS PAGE.IT HELP ME TO KNOW HOW I CAN INCREASE MY HEMOGLOBIN.
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Nov 5, 2012 @ 10:22 pm
I FEEL GREATFULL TO VISIT THIS PAGE ! SIR PLZ HELP ME, MY SON 1YEAR 4 MONTHS WHO IS SUFFERING WITH LOW HEMOGLOBIN LEVEL
HISTORY :AT THE TIME OF BIRTH DUE TO DELAY IN DELIVERY HE HAD PASSED THE MOTION INSIDE HIS MOTHER STOMACH AND SWALLOWED THE MOTION PARTICLES THAT WAS ACUMALATED IN HIS LUNGS THAT RESULT HE WAS IN VENTILLATOR AND TREATED FOR 22 DAYS WITH HIGH DRUGS AND FINALLY HE WAS SURVIVED.AFTER 6 MONTHS WE ODSERVED THAT HE IS BECOMING WEAK & PALE IN COLOUR AND FOUND THAT HEMOGLOBIN LEVEL IS VER LOW.
EVEN THOUGH 2 TIMES BLOOD TRANSFUSION IS DONE BUT AFTER 1 MONTH IT IS AGAIN BACK TO ITS BAD LEVEL( 4 %).SEVERAL TEST LIKE BONEMARROW ASPIRATION & BIOSPY ETC MANY TEST ARE DONE BUT ALL ARE RESULTED TO NORMAL THEY ARE UNABLE TO DIOGNAISE ?
WE ARE VERY WORRIED ABOUT OUR CHILD ,WHAT IS THE CORRECT PROBLEM ? PLEASE TELL US WHAT CAN WE DO ? AND HOW TO CURE IT ? PLEASE HELP US.
CONTACT NO :+919000972345.
boopathy
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Nov 7, 2012 @ 9:09 am
if the amount of hemoglobin is 6.00, what diseases causes women?and the age of women is 85years old, Plz told about treatment,
Daphne
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Nov 14, 2012 @ 9:21 pm
I am 15 yrs. old female and when I went to the doctors office this week for my cold, once everything was done
my doctor gave me a lab report. It said that I had to do a hemoglobin test, should I be worried?
My health is normal, but I'm not sure what this test means? Please HELP?!?!
john
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Nov 29, 2012 @ 12:00 am
Wow! Just reading this is scarey. We just took my 53 year female friend to hoppital because her hemoglobin level was 3.6
richard young
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Dec 28, 2012 @ 11:11 am
my mom has a pace maker we check her blood to see thickness yesterday the nurse said 1.8 is that to thin and can she eat greens to get it to come up some?
Sandy
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Jan 5, 2013 @ 5:17 pm
I also have high hemmoglobin levels I am 53 yrs old mine are 21 , I also have been told I have polycythemia vera secondary it has taken a year to figure that out I also have bone marrow biopsy they. Checked me for jak2 mutant in my bone I have vented blood I still see a cancer d still dont know whats going on i know i had to go on oxegen my level are 81 and i know i cant breath, also i am a smoker who needs to quit desperateally .So I hope god gives me the strength I need to quit before they kill me , Doctors can't help me if I can't help myself , So I honestly Don't know What's the next journey with the polycythemia vera I do know it can and will attack kidneys and liver next if hemmoglobin levels don't go down I also know that high hemmoglobin levels that your supseptical to blood clots and blood to thick to g o thru vital organs . That's All the Knowledge have looking to learn more gl. Everyone
brendan
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Apr 21, 2013 @ 4:04 am
my wifes memoglobin was 16.5 but doctor not done anything yet or explained to her why,she to go in june this year 2013 and give motr blood,she trying to cut smoking,doesnt really smoke that much any how but because both parents have heart5 problems she worried,well that yous all know how she gets on thanks for listening
ANURADHA
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Aug 26, 2013 @ 7:07 am
HEY...
MY HAEMOGLOBIN LEVEL IS 8.5, WHAT SHOULD I DO ??
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Feb 14, 2014 @ 2:14 pm
My WBC IS 8.9 but my HGB is 11.0 presently. What should i do? I feel dizzy all the time and nausea the Hgb was 14 last September 2013 and its now 11.0 at 2014. What could this mean I'm so afraid that i may die. doctor said i was iron deficiency, hes treating me for that by giving me FERRUM FOL Iron tablets but notthing is working instead my Hgb is dropping every month. Please help me.
TINA
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Apr 16, 2014 @ 4:16 pm
IS IT NORMAL FOR MY 3 YEAR OLD SON TO HAVE A 13 ON HIS HEMOGLOBIN BLOOD TEST AT HIS WELL CHILD CHECK?
krishna
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May 3, 2014 @ 7:07 am
Hi Sir,My father haemoglobin level is 7.4,what should i do,wat to do to increase the blood level?
pari
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Jun 8, 2014 @ 12:00 am
what is effect of low HB abt 8 on married life of male
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Jun 8, 2014 @ 1:01 am
My frind male 32 yaer ,and his Hemoglobin Fluctuating 7.50(HB) to 11(HB) between atfer the birth .He is looking normal but his color yelow.. plz tell me he is the able to marrige life .
Saleem Sikander
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Jun 8, 2014 @ 1:13 pm
My sisiter is 30 years and her humoglobin was 6.8. Then i started her to give fruit and juices her humoglobin became 8.1. Then again i checked then 7.7. Now she is taking surbex z tablet daily once and feel nrml. What should i do now?
roshi
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Jul 20, 2014 @ 12:00 am
thank you sir for your valuable information
sir
my mother, aged 58 now suffering for low hb level that is 7.92 and she is having hectic back pain and head ache .when we have culture test on her urine last two months back it shows she have urinary infection sir
pls suggest wat can we do to over come this also suggest what all fuood should be given for to increas her blood count

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