Analysis Of Blood Is Now A Key Tool Biology Essay

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Analysis of blood is now a key tool in many fields of work such as by health care professionals and forensics as it holds valuable information. In a forensic setting blood analysis is used to help solve crime in which tests are done to work out blood type or even analysed for bacteria to help aid in reconstructing timelines whereas in a health care setting blood analysis is done involving several tests to detect many diseases and disorders. One of the most common uses for blood analysis is in medical tests in which many factors are analysed such as a patient's general health, the presence of bacterial/viral infections or even to see how well body organs such as the liver and kidney are functioning. Blood is made up of approximately 40% of blood cells being red blood cells, white blood cells or platelets and the remaining 60% is made up of plasma consisting of mainly water although it may contain proteins and other chemicals such as hormones and glucose. Because the blood is made up of this family of constituents it is an ideal method of detecting inconsistencies from normal blood content. A good example of this would be in the case of diabetes mellitus which is characterised by elevated blood glucose levels, tests are carried out in which a drop of blood is analysed for glucose content and compared to the normal range to either determine the patient has diabetes or for monitoring glucose levels daily as a management step to control glucose levels.

Some everyday blood tests used are red blood cell counts, used to determine increase or decrease of red blood cells but however this information is not usually enough and so this test is used in conjunction with other tests involving haemoglobin, haematocrits and other red blood indices such as mean corpuscular volume (MCV). Depending on the results from these tests the presence of a disorder can be determined for example, if the haematocrit has been found to be decreased the patient may have anaemia or if the haematocrit is found to be raised then the patient may have polycythemia, however other tests as well as the haematocrit analysis are required to confidently diagnose disorders.

Acute dehydration affects the contents of the blood as water in the plasma is lost thereby making the blood more concentrated and also raising the haematocrit leading to many inconvenient complications.

In this experiment abnormalities in blood will be investigated by analysing haematocrit content, performing red blood cell counts, performing a plasma and total haemoglobin count and also calculating percentage haemolysis. Also, the effect of acute dehydration will be investigated by haematocrit analysis and haemoglobin measurement.

Method

See schedule

Results

Table 1: Haematocrit analysis of 4 samples of blood to observe any abnormalities

Sample

HCT /

% PCV

A

0.48

48

B

0.64

64

C

0.55

55

D

0.30

30

Table 2: Colour observations of the supernatant of the four blood samples after centrifugation

Sample

Colour Observations

(tube 1)

Colour Observations

(tube 2)

A

Solid Orange

Solid Orange

B

Solid Yellow

Solid Yellow

C

Pale Yellow

Pale Yellow

D

Solid Dark Red/Brown

Solid Dark Red/Brown

Table 3: Red blood cell count for each of the four blood samples to calculate the undiluted red blood cell count (N) expressed as cells / litre

Sample

Square 1

Square 2

Square 3

Average (RBCSS)

Undiluted RBC Count (N) / cells/Litre

A

178

169

172

173.00

1.39092 Ã- 1014

B

157

183

154

164.67

1.32392 Ã- 1014

C

104

96

93

97.67

7.8524 Ã- 1013

D

73

53

64

63.33

5.092 Ã- 1013

Table 4: The absorbance values obtained under 380nm, 415nm and 450nm wavelengths in the spectrophotometer to calculate out HaemP

Absorbance

Sample

380nm

415nm

450nm

HaemP (g/l)

A

0.006

0.011

0.007

1.22

B

0.011

0.009

0.014

0.35

C

0.005

0.005

0.008

0.28

D

0.191

0.809

0.110

117.44

Table 5: The absorbance values obtained under 380nm, 415nm and 450nm wavelengths in the spectrophotometer to calculate out HaemT

Absorbance

Sample

380nm

415nm

450nm

HaemT (g/l)

A

0.400

1.582

0.250

214.33

B

0.481

1.902

0.296

257.98

C

0.481

1.874

0.299

253.10

D

0.262

0.920

0.151

121.81

Table 6: The percentage haemolysis observed in the four blood samples calculated from HaemP and HaemT to identify the number of cells undergone haemolysis

Sample

HaemP

HaemT

% Haemolysis

Number of cells undergone haemolysis

A

1.22

214.33

0.57

8.06251 x 1011

B

0.35

257.98

0.14

1.79832 x 1011

C

0.28

253.10

0.11

88076655967

D

117.44

121.81

96.42

1.37152 x 1015

Graph 1: The percentage difference observed of MHC, BV, CV and PV when a blood sample was subjected to acute dehydration calculated for 4 hour intervals.

Tube

Sample

abs

av.abs

Hb(g/l)

Hct

%PCV

MCHC (g/l)

%∆MCHC

%∆BV

%∆CV

%∆PV

540 nm

540nm

 

 

100xHct

Hb/Hct

*

**

***

****

Standard curve data

0

Blank

0

0

0

n/a

n/a

n/a

n/a

n/a

n/a

n/a

1

std1

0.105

0.105

50

n/a

n/a

n/a

n/a

n/a

n/a

n/a

2

std2

0.205

0.205

100

n/a

n/a

n/a

n/a

n/a

n/a

n/a

3

std3

0.321

0.321

150

n/a

n/a

n/a

n/a

n/a

n/a

n/a

4

std4

0.432

0.432

200

n/a

n/a

n/a

n/a

n/a

n/a

n/a

5

std5

0.546

0.546

250

n/a

n/a

n/a

n/a

n/a

n/a

n/a

 

 

 

 

Hb0

Hct0

%PCV0

MCHC0

 

 

 

 

6

N0 (T= 0 hrs) 

0.345

0.389

170

0.36

36

472.2

0

0

0

0

7

0.432

 

HbT

HctT

%PCVT

MCHCT

 

8

 N1 (T= 4 hrs)

0.452

0.454

210

0.38

38

552.6

17

-19

-14.6

-21.5774

9

0.455

10

 N2 (T= 8 hrs)

0.457

0.459

215

0.40

40

535.8

13

-21

-12.1

-25.8721

11

0.460

12

 N3 (T= 12 hrs)

0.483

0.509

235

0.45

45

522.2

10

-28

-9.6

-37.8324

13

0.535

14

 N4 (T= 16 hrs)

0.561

0.569

265

0.47

47

563.8

19

-36

-16.2

-46.875

15

0.577

16

 N5 (T= 20 hrs)

0.580

0.585

270

0.48

48

562.5

19

-37

-16

-48.8426

17

0.589

Table 7: Blood analysis of Hb, Hct, %PCV and MCHC as well as the differences observed when a blood sample was subjected to acute dehydration. The results for the sample were obtained after 4 hour intervals to be compared with a known standard.

Discussion

Below are a set of normal reference ranges of blood constituents when blood tests are analysed.

Haematocrit

Male: 45 - 62%

Female: 37 - 48%

Haemoglobin

Male: 13 - 18 gm/dL

Female: 12 - 16 gm/dL

Mean Corpuscular Haemoglobin (MCH)

27 - 32 pg/cell

Mean Corpuscular Haemoglobin Concentration (MCHC)

32 - 36% haemoglobin/cell ( 320 - 360 g/L )

Mean Corpuscular Volume (MCV)

76 - 100 cu µm

Platelet Count

150,000 - 350,000/mL

White Blood Cell Count

4,300 - 10,800 cells/µL/cu mm

Red Blood Cell Count Male: 4.7 to 6.1 million cells per microliter (cells/mcL)

Female: 4.2 to 5.4 million cells/mcL

The reference ranges were taken from http://www.bloodbook.com/ranges.html.

An important note to be taken into account is that the reference ranges are different for different genders in which males seem to have a broader range to be classified as being within normal boundaries. These reference ranges play a key role in diagnosis of disease as the diagnosis is based on whether certain components have increased, decreased or stayed the same. The haematocrit measure the volume of red blood cells in comparison to the total blood volume (including plasma) an shows how concentrated the blood is. Disorders such as erythrocytosis and anaemia arise from the blood contents drifting away from the normal reference range values; in particular for these two particular disorders the haematocrit and haemoglobin values are used.

According to Hodges et al (2007), anaemia is a deficiency of functional red blood cells leading to a loss of oxygen carrying capacity, tissue hypoxia and a variety of clinical consequences to include fatigue, increased cardiac output and a poor quality of life. There are many reasons why anaemia occurs, the most common worldwide reason is due to iron deficiency as a result of lack of vitamin B12 being in the diet or problems in the absorption of the vitamin. Erythrocytosis is defined as an increase in circulating red blood cells which suggests the process of erythropoeisis may be active more than normal stimulating the production of red blood cells. Erythrocytosis refers to elevated red blood cells from the red cell lineage and should not be confused with polycythaemia vera which also means a rise in red blood cells but as result of a stem cell disorder causing excessive production of red blood cells. Haemolytic anaemia is the abnormal breakdown of red blood cells as a result of the process of haemolysis and can be detected in a blood sample by analysis of haemoglobin in the sample as defects in haemoglobin production has been associated with causing haemolytic anaemia.

The HCT values in table 1 for the four patients suggest that patients A, B and C had a normal haematocrit value whereas patient D had a low HCT value to that of the normal reference ranges listed earlier. From the colour observations in table 2, the tubes A, B and C ranged from a similar looking yellowy-orange colour whereas tube D had a distinct colour difference compared to the others in which it was a dark red/brown colour which indicates that the sample may be more concentrated in red blood cells. Based on results from table 3, the red blood cell count was lowest in patient sample D compared to the other samples indicating less red blood cells being formed. From table 6 a very high percentage of cells that underwent haemolysis were observed compared to other samples. Based on patient D's sample having a low HCT value, possessing the lowest cell count and having a very high haemolytic lysis percentage it can be concluded that sample D has haemolytic anaemia. Samples A, B and C seem to be fairly normal based on these results an reference ranges used however, sample A may have erythrocytosis as it presented with the highest cell counts as seen in table 3 which is what is expected in the erythrocytosis although a high HCT is usually observed also which is not confirmed by the current results.

Acute dehydration plays a part in affecting certain constituents of blood such as the haematocrit and haemoglobin as these values take into account the whole blood and therefore makes them dependent on plasma volume. As seen from table 7, after every 4 hours the HCT levels in the blood began to increase gradually providing evidence to propose that dehydration affects haematocrit levels by increasing them.

The MCHC is the concentration of haemoglobin in given volume of packed cell volume and considered to be normal around 320 - 360 g/l. As observed in table 7, all the values obtained are consistently high, well above the normal range. When comparing N1-N5 to N0 the MCHC is higher even though at N0, the MCHC value is not within the normal range a relationship is still observed as more time passed the MCHC was consistent and finally became higher. The fact that MCHC is raised under dehydration condition complies with what is expected in acute dehydration conditions. As observed in graph 1 the MHCH had a maximum of a 20% difference in the latter part of the dehydration time (N4 and N5) also confirming that MHCH is increased during acute dehydration. Also from the graph it can be seen that no effect on BV, CV and PV occurred as the results were all negative indicating no difference occurs as a result of acute dehydration.

According to Harrison (2006) apparent erythrocytosis results when there is no increase in red cells but they are more concentrated where as in "true"/absolute erythrocytosis an increase in red blood cells is observed. The increase in concentration is most likely due to a reduction of plasma in apparent erythrocytosis. To distinguish between the two when analysing the blood if red cell mass is raised and plasma levels fall between the normal range then this would be classified as absolute erythrocytosis whereas in apparent erythrocytosis the red cell mass would fall within the normal range and the plasma levels would be raised. The fluid loss aspect of dehydration presents mild symptoms early on beginning with feeling thirsty and as time progresses in the absence of refuelling the body with fluids the symptoms become worse and more serious. When dehydration progresses to a moderate stage it could lead to loss of strength and as stated by the NHS (2010), it could lead to loss of kidney function if dehydration is chronic and in worse cases could lead to death if 10% of the body weight is lost as a result of dehydration.

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