Hematocrit



Definition

The hematocrit is a test that measures the percentage of blood that is comprised of red blood cells.


Purpose

The hematocrit is used to screen for anemia, or is measured on a person to determine the extent of anemia. An anemic person has fewer or smaller than normal red blood cells. A low hematocrit, combined with other abnormal blood tests, confirms the diagnosis. The hematocrit is decreased in a variety of common conditions including chronic and recent acute blood loss, some cancers, kidney and liver diseases, malnutrition, vitamin B 12 and folic acid deficiencies, iron deficiency, pregnancy, systemic lupus erythematosus, rheumatoid arthritis and peptic ulcer disease. An elevated hematocrit is most often associated with severe burns, diarrhea, shock, Ad dison's disease, and dehydration, which is a decreased amount of water in the tissues. These conditions reduce the volume of plasma water causing a relative increase in RBCs, which concentrates the RBCs, called hemoconcentration. An elevated hematocrit may also be caused by an absolute increase in blood cells, called polycythemia. This may be secondary to a decreased amount of oxygen, called hypoxia, or the result of a proliferation of blood forming cells in the bone marrow (polycythemia vera).

Critically high or low levels should be immediately called to the attention of the patient's nurse or doctor. Transfusion decisions are based on the results of laboratory tests, including the hematocrit. Generally, transfusion is not considered necessary if the hematocrit is above 21%. The hematocrit is also used as a guide to how many transfusions are needed. Each unit of packed red blood cells administered to an adult is expected to increase the hematocrit by approximately 3% to 4%.


Precautions

Fluid volume in the blood affects hematocrit values. Accordingly, the blood sample should not be taken from an arm receiving IV fluid or during hemodialysis. It should be noted that pregnant women have extra fluid, which dilutes the blood, decreasing the hematocrit. Dehydration concentrates the blood, which increases the hematocrit.

In addition, certain drugs such as penicillin and chloramphenicol may decrease the hematocrit, while glucose levels above 400 mg/dL are known to elevate results. Blood for hematocrit may be collected either by finger puncture, or sticking a needle into a vein, called venipuncture. When performing a finger puncture, the first drop of blood should be wiped away because it dilutes the sample with tissue fluid. A nurse or phlebotomist usually collects the sample following cleaning and disinfecting the skin at the site of the needle stick.


Description

Blood is made up of red blood cells, white blood cells (WBCs), platelets, and plasma. A decrease in the number or size of red cells also decreases the amount of space they occupy, resulting in a lower hematocrit. Conversely, an increase in the number or size of red cells increases the amount of space they occupy, resulting in a higher hematocrit. Thalassemia minor is an exception in that it usually causes an increase in the number of red blood cells, but because they are small, it results in a decreased hematocrit.

The hematocrit may be measured manually by centrifugation. A thin capillary tube called a microhematocrit tube is filled with blood and sealed at the bottom. The tube is centrifuged at 10,000 RPM (revolutions per minute) for five minutes. The RBCs have the greatest weight and are forced to the bottom of the tube. The WBCs and platelets form a thin layer, called the buffy coat, between the RBCs and the plasma, and the liquid plasma rises to the top. The height of the red cell column is measured as a percent of the total blood column. The higher the column of red cells, the higher the hematocrit. Most commonly, the hematocrit is measured indirectly by an automated blood cell counter. It is important to recognize that different results may be obtained when different measurement principles are used. For example, the microhematocrit tube method will give slightly higher results than the electronic methods when RBCs of abnormal shape are present because more plasma is trapped between the cells.


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 no complications associated with this test.


Normal results

Normal values vary with age and sex. Some representative ranges are:

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

Also read article about Hematocrit from Wikipedia

User Contributions:

1
kifah
i want to ask question why centrifuge the hematocrit for only five minute

thank you
2
Sehar Raza
i want to ask question why centrifuge the hematocrit for only five minute
3
Vivian
Why when the blood glucose level increase the hematocrit is decrease and when hematocrit increase then the blood glucose level decrease?
4
HENRY
please after test of hematocrit i got 51.2 am henry from spain am 23 years is it ok to my body....thanks i need reply.BYE
5
Cleo Pease
I'm a student LPN and doing a case study. Have a pt who has low RBC and hemocrit. Hemoglobin is normal. Pt has liver cancer and metastasis to bones. I'm trying to find a more definite reason for these low levels. Any help I'd appreciate it.

Thank you
Cleo
6
Cecille
I want to donate blood but test result showed that my hematocrit is below range by 1 point. How can i increase my hematocrit so that i can donate blood... thank you
7
gee1970
my wife is 7 months pregnant and has a hematocrit (PCV) of 29% with feverish feelings and headache, pls explain to me is it associated
what to for a five months pregnancy of hematocrit pvc test of 25%
basic and informative and also easy to understand.
I want to know hos some drugs like penicillin or chloramphenicol can affect the hematocrit
may i know manual (Microhematocrit) method packed cell volume detection,thank you
Hi,

I just got discharged from Hospital after Dengue Fever. Twice blood tranfusions were done to increase the Blood Platlet counts. Now although the Platlets have recovered to normal level of 180K, but PCV value is also increased to 46.1
I am confused as to what is normal level of PCV, as the Lab says it should be within 39 to 46. I am unaware of my normal PCV value. However I remember my Hb count was 16, around one year back when I donated blood. So is there a direct correlation o high Hb count with high PCV value.


Regards
Harish
13
Martin Kalumbi
May i know factors which can falsely elevate or reduce manual PCV?
14
Troy
Why when the blood glucose level increase the hematocrit is decrease and when hematocrit increase then the blood glucose level decrease?
15
Osas
I am pregnant, and my PVC is 28 what is the cause, and what i do to increased it?
16
anna
I wanted to give plasma but my hematocrit was too low by 1 point. What can I do to safely increase it? Thank you.
17
Jazz
What are the ways to perform and hematocrit test and the equipment needed?
18
Frank
a pregnant woman with 27 PVC, please what could be danger in her life and how does she come out it?
19
Rene j morin
I have polysistic kidney disease. My latest test was 33.6 hemotrocit.Can I increase this number by diet such as iron rich food such as liver or clams? Thank you Rene Morin
20
philip ibonye
i have an eleven+ month old son, since 2 weeks he has falling sick having high fevers,several test has been run and the doctors keep saying he has infection that the blood PCV level is high, recently we were told that his WBC are more than his RBC, he has been on antibiotics and anti malaria almost every month, what advice can you give please.
21
Oby
My pcv is30 percent? What does it mean and what do I do?
22
Adeosun
I'm pregnant and my pcv is 32percent is it ok or normal if is not what should i take to correct it pls i need an urgent reply thanks.
23
almas
what is haematocrit and mine is 31.5 so what needs to be done
24
Nenye
Am in my nine months pregnant and my pcv 30%,what can i do
25
mrs kelechi
i am pregnant and went for my pvc test, just to find out that my pvc is 24percent, is it too poor for delivery or is it ok? what do i do?
26
Oby Ofoegbu
Hello, my hemoglobin is 7 and my Hematocrit/PCV is 20%. Is it abnormal and should I be worried? I am a 39 year old female
27
TaiwoAbiodun
Pls how can I improve my PVC am six month pregnant and my PVC is 30% which I know is not good for me. Pls I need help urgently. Thanks.
28
stella
i am 36 weeks pregnant, I take my routine drugs and eat healthy. My last PCV test was 35% at 32 weeks but at 36 I'm told that my PCV is 32%. Pls how can I improve my PCV? Tnx.
29
bolanle
I want to a question, pls am 8month pregnant my PCV is 32%.what do I need to do to increase it.Reply soonest pls.
30
stacy
I have. Critical high HCT 51.8 what does this mean?
31
Oby E
Question--i am 30 weeks pregnant and my pcv is 29%,want to know if its ok for delivery..and if not what can I do to increase it..please what's the normal pcv level that must be attained before delivery
32
jummy
Am 37 weeks pregnant and my pcv was 29%,and the doctor said it was low. Pls how can I increase the blood level and peradvance I went into labour, what is the risk of delivery.
33
Aderemi
I am 30-33 weeks(My LMP was 17th April 2013 snd today is 08/12/2013)My scan results keeps showing 30 weeks)but my PCV level is 27percent)pls am I okay?I hope I am good with it?pls respond quickly.
34
Murja
What is the nomal pcv for a pregnant women.pls i need ugent answer.
35
nikky
Am in my 7th month pregnancy and My blood pcv is 28%,is it ok?
36
lizz
Please Am 8 months pregnant and my pcv is 32% Please how can I improve it
37
afolasade
Am in my 17wks pregancy and my pvc is 28%,please how can i improve it.
38
pouliwe bennair
What does prolonged bleeding time signify and also the complications in blood transfusion and also the aspect of homeostasis does in clotting time assess.
39
Laide
I am almost six month pregnant my PCV is 30% is it ok any precaution and how do I increase it if need be.
40
benneth
3 months pregnant and pcv is 32% is it very low , ok ;if too low how can i increase
41
barakat
I'm 26weeks pregnant and my pcv was 33percent when I was in week 23 and ve been on pregnant care sine d time I dis covered that I conceived and becauce of d 33percent PCV my doctor added verrous,folic acid and vitaminc to it and I took feroglobin for a week with it again buh despite all,I did another PCV again now at week 26 and d result is 30percent. Please what can I do?
42
oreh
I am 38weeks and my pcv is 30,please is this safe for delivery?
43
francess
Please am 24 weeks pregnant and my pic is 26 what should I do to increase it
44
bJ
Am in 33wks+1wk. My pcv is 34per is it ok for my delivery. Or what is the highest level require of me at my delivery stage
Hello!My PCV is 52%,male,19yrs.Hope my PCV is okay 'cause I heard too much of Iron in the blood is not okay.Thanks!
46
harsh
Hi my age is 22 yrs & live in agra (india) my hb is ,16.7 And pcv/haematocrit is 52.2 &rbc are 6.34 Please tell me am I ok
47
Larry
Hi, pls am a male of 28yrs and my pcv level is 45% I usually feel dizzy and eye heavy headed. Pls is my pcv ok.
48
rumar1
I am 28 years old, please I have being suffering from migraine and some drugs were prescribed to me by a Doctor, after taking the drugs I had a relief of the migraine but there was allergic reaction that developed rashes on my body and also triggers my ulcer by octalidon. and the migraine is still attacking me. while am still on ulcer drugs.
And my PCV count was 54%. please I need your help as am always suffering from stomach and back pain, the migraine its self and dirrhhea.
What's the correlation between hemoglobin level and hematocrite (parked cell Level) since they both deal with blood level? But I guess hemoglobin deals with iron content in blood of an individual and PCV deals with the red blood cell of an individual am I right Or there is any other attachment?
50
Holland
I donate plasma to supplement my fixed income. Lately, the lab has denied me from donating due to elevated hematocrit levels. Their limit is 54, and twice in the past 3 weeks my hematocrit levels were 55 and 56. The other times the levels were 43, 51, and 53. I desperately need the money, so I'm looking for ways to reduce my hematocrit levels. I have done a lot of research, so I already know about hydration, avoiding foods high in iron, consuming grapefruit or grapefruit juice, etc. etc. I take several prescription medications, including Gabapentin, hydromorphone, and diazepam. I only take these exactly as prescribed. Any suggestions, ideas, recommendations, regarding how I can reliably reduce my hematocrit levels would be greatly appreciated. Other than the spinal damage, and non diabetic neuropathy, for which I take the above mentioned medications, I am a healthy 61 year old male.
51
Holland
I donate plasma to supplement my fixed income. Lately, the lab has denied me from donating due to elevated hematocrit levels. Their limit is 54, and twice in the past 3 weeks my hematocrit levels were 55 and 56. The other times the levels were 43, 51, and 53. I desperately need the money, so I'm looking for ways to reduce my hematocrit levels. I have done a lot of research, so I already know about hydration, avoiding foods high in iron, consuming grapefruit or grapefruit juice, etc. etc. I take several prescription medications, including Gabapentin, hydromorphone, and diazepam. I only take these exactly as prescribed. Any suggestions, ideas, recommendations, regarding how I can reliably reduce my hematocrit levels would be greatly appreciated. Other than the spinal damage, and non diabetic neuropathy, for which I take the above mentioned medications, I am a healthy 61 year old male.
52
Lisa
My son is in remission from leuekmia but in last week he's quite pale so took him docs and had blood test his hb is normal but his haematocrit is saying below range do I need to be worried x
53
Lisa
My son is in remission from leuekmia but in last week he's quite pale so took him docs and had blood test his hb is normal but his haematocrit is saying below range do I need to be worried x
54
Nia
I am 7 months pregnant. This morning received blood test results.. Red Blood cells 3.400 Hemoglobin 9.2 and hematocrit 11 should i be worried?
55
Ph gaith
What dose the dehydration on the hematocrit . I'm very nedded to study . Thank you
56
holitoli
my nephew has a packed cell volume of 39% . he is 6years old. is it serious?..what treatment should be given?please help
57
Ajay
I am 28 year old. My pcv 48 and hb 15.80 loose motion but no pain wt resion loose motion, am cheked colonscopy,and altrasound report normal
58
oyindamola
Am 24 years old with 36% pcv of twin pregnancy is it good and what should I hard to increase it.
59
oluwatoyin oyindamola
33 weeks of twin pregnancy with pcv of 36% is it OK for delivery?
60
George
Hello.. I am 23 years pls, i just did test and my PCV READS 41% and HB is 14.1%... I need to know if these is d normal range coz the physician mentioned that i look pale. Dats it have to do with my diet?. How can i improve?
61
david
Pls can I donate blood with 40% pcv. I wish to be a donor and I think my pcv is low
62
jerry
My daughter who will be 12 years by February did a PCv and the result show that it's low at 30% that the normal range is 35-54%. Kindly advice me the implications, causes and the treatment. Thanks
63
Amy
Please my hematocrit is 29.6percent and I am just about 8weeks pregnant. I am soo worried,what can I do.
64
Sofiat Ibrahim
Am pregnant even close to delivery now and my PVC is 29 what is the cause, and what can I do to increased it?please is urgent and am also worried!!
65
Susan Tosin-Awe
Am pregnant and my PCV is 32.
What should I do?
Is it safe for my delivery
66
Rogelio delgado
Hi, i am 26 years old and we just did a hematocrit test in my physiology lab via finger prick. My buffy layer was a lot larger than normal and i am wondering why that could be. I did have to prick my finger several times and sometimes in/around the same spot. Could it just be plaletes due to me clotting quickly?
67
M S Siddalinga Swamy
My WBC count is 13.35(10^3/ul), PLT283 (10^3/ul)HGB 13.6 g/dL,RBC5.01(10^6/ul) etc is this condition is normal I am 62 yrs old known Diabetic since 10yrs,
68
Sarah
I am 3months pregnant and my PCV is 36%, will my PCV continue to decrease as the months increase? Please I want to know.

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