Blood morphology - what does it show and when to do the test? .

The blood count is one of the most frequently performed tests - also in pregnancy. It enables the components of the blood to be analysed and thus allows abnormalities to be detected before they produce visible symptoms. What does the test look like and what can you learn from the results?

Morphology - what is the test?

Peripheral blood morphology is basic diagnostic examination performed on the basis of a venous blood sample. The collection of the material allows for the quantitative and qualitative analysis of blood cells (i.e. morphotic elements of the blood).

These include^[1]:

• erythrocytes (red blood cells),

• leukocytes (white blood cells),

• thrombocytes (platelets).

The blood morphology contains information on the patient's general state of health and allows early detection of many diseases and abnormalities, the symptoms of which are not yet felt by the person concerned. In the event of an abnormal result of any of the morphology indicators, the doctor may recommend the following additional studies (both laboratory and imaging) to further the diagnosis.

With peripheral blood counts it is possible to detect, among other things:

• infections (even in the initial, asymptomatic stage),

• allergies,

• immune disorders (as well as autoimmune diseases),

• inflammatory conditions,

• diabetes and pre-diabetic conditions,

• different types of anaemia,

• tumours,

• diseases of the blood and haematopoietic system.

Doctors recommend a follow-up morphology at least once a year.

However, the study should be considered by those with symptoms such as:

• a constant feeling of fatigue, general weakness,

• rapid weight loss, unrelated to diet or increased physical activity,

• recurrent infections,

• muscular-articular pains of unknown cause,

• slowed wound healing, tendency to bruising and bloody petechiae.

Morphology shall also be performed in patients preparing for surgery or people who are to become bone marrow or organ donors. It is also a particularly relevant study for pregnant womenallowing for ongoing health monitoring.

Complete blood count vs. baseline blood count

Depending on the need, the patient may be referred for a baseline or full blood count.

W baseline morphology parameters such as^[1]:

• RBC (red blood cells) - erythrocyte count,
• WBC (white blood cells) - leukocyte count,
• PLT (platelet) - platelets,
• haematocrit - the ratio of the volume of blood cells to the volume of whole blood,
• Hb - haemoglobin, total haemoglobin concentration.

In turn complete morphology, also known as morphology with smear, is a qualitative assessment that not only examines the number of a specific group of blood cells, but also evaluates their structure. It is enriched by^[2]:

• additional red cell parameters:
  • MCV - an indicator of mean erythrocyte volume,
  • MCH - determination of the average haemoglobin mass in a single blood cell,
  • MCHC - mean haemoglobin concentration in blood cells,
  • RDW - erythrocyte differentiation index,
  • RET - reticulocytes, or young erythrocytes, and basically their ratio to adult forms of red blood cells,

• additional white blood cell parameters:
  • automated smear - differentiating and counting individual leukocyte fractions, i.e. lymphocytes (LYM), monocytes (MONO), neutrophils (NEU), basophils (BASO) and eosinophils (EOS),

• additional platelet parameters:
  • MPV - mean platelet volume,
  • PDW - platelet volume variation,
  • PCT - platelet haematocrit, indicating the ratio of platelet mass volume to total blood volume,
  • P-LCR - the number of so-called large platelets (larger than the norm).

In addition, the ESR (Passer's reaction, so-called precipitation), which is the rate at which the red blood cells fall, is also determined in the morphology.

It is now customary to perform a complete morphology, as it gives a much better picture of the patient's overall health and provides much more accurate diagnostic information than a baseline morphology.

Blood count and pregnancy

Morphology in pregnancy should be performed several timesso that the health of the mother-to-be can be monitored and reacted to quickly if any abnormalities are detected.

At such a difficult time for a woman's organism as pregnancy, even small deviations from the norm can have an impact on the baby growing in the womb. This is why, according to the recommendations of the Ministry of Health, a pregnancy morphology should be performed at least five times:

• up to the 10th week of pregnancy,
• Between the 15th and 20th week of pregnancy,
• Between the 27th and 32nd week of pregnancy,
• Between 33 and 37 weeks of pregnancy,
• just before dissolution.

It is worth knowing that during pregnancy, certain physiological changes in certain values in blood morphology results^[1]. These are:

• decrease in haemoglobin concentration,
• decrease in haematocrit,
• reduction in erythrocyte count,
• increase in the number of leukocytes.

Although some decrease in red blood cell parameters is due to the physiology of pregnancy, its constant control is very important for the health of both mother and foetus. Severe anaemia, in addition to general symptoms such as fatigue, lethargy or headaches, may lead to abnormalities in placental development, stunted growth of the foetus and, in extreme cases, even its death. Therefore, pregnant women should carefully monitor their

general condition and well-being and, in the event of abnormalities in the results of recent tests, perform a morphology more frequently than recommended^[1].

In the context of preparing for the in vitro procedure The blood count test is crucial for the performance of anaesthesia. It is therefore recommended to have it done in the month before the procedure (preferably as close as possible to the day of the procedure).

How to prepare for the study?

Blood morphology - both baseline and complete blood count - is performed from a venous blood sample. You must be fasting for the intakewhich means eating your last meal at least 12 hours before the test. It is advisable to limit alcohol and all stimulants (including caffeine) for a few days before the CBC.

Blood collection should be performed in the morning - preferably between 7:00 and 10:00.

For women, it is not advisable to perform the test during menstruation, as menstrual bleeding can have a significant impact on lowering parameters (especially red blood cells).

How to read blood count results? Norms for individual parameters

The patient receives the results of the blood count in the form of a printout, on which the individual lines refer to successive morphotic elements.

The first column shows the abbreviations referring to the English names of the subsequent elements. Then, depending on the standard adopted by the laboratory, there is the result, the unit of calculation, the reference range of the standard and, if the result obtained is outside the standard, there is additionally an arrow or letter indicating that the standard is exceeded upwards (up arrow or letter H - high) or downwards (down arrow or letter L - low).

Range of reference standards is presented in the table below^[2]:

Blood element	Standard for women	Male standard
RBC	4-5.4 M/µl	4.5-6 M/µl
HGB	12-16 g/dl	13-18g/dl
HCT	37-47%	40-51%

MCV	81-99 fl	80-94 fl
MCH	27-32 pg
MCHC	32-36 g/dl
RET	5-15‰
OB	3-15 mm/h	10 mm/h
WBC	4-10,000/µl
LYM	0.6-4.1 thousand/µl (20-45%)
MONO	0.1-0.4 thousand/µl
NEU	2.5-6.5 thousand/µl
EOS	0.1-0.3 thousand/µl
BASO	< 0.1 thousand/µl
PLT	140-440 thousand/µl
PDW	40-60% (6.1-11 fl)
PCT	0.16-0.34 %
P-LCR	<30%

In pregnant women the norms are slightly different due to the increased amount of circulating blood, for example. Parameters such as^[1]:

• HCT - 36-46%,
• HGB - 12-16 g/dL,
• WBC - 4.8-10.8 thousand/µl,
• PLT - 150-450,000/µl.

In addition, there is a gradual increase in ESR during pregnancy, which in the last trimester may even give a 3-digit result.

The results obtained should be consulted with your doctor. Some slight deviations from the norm can be caused by lifestyle, diet or medication. Therefore, for a complete interpretation of the morphology results, a thorough history is always necessary, which will juxtapose the results obtained with the patient's medical history.

From the point of view of the pregnant patient, the most important are red blood cell indices. Poor erythrocyte morphology results may indicate progressive anaemia. In such a case, the doctor usually refers for additional blood tests to determine the patient's iron and ferritin levels.

Elevated red blood cell results may indicate an ongoing inflammatory process, infection or infestation. Reduced white blood cell results, on the other hand, may indicate immunodeficiency states.

For a more in-depth diagnosis and certainty about the condition, you may need to additional studies - both laboratory (e.g. urinalysis, peripheral blood biochemistry) and imaging (e.g. ultrasound or MRI).

Blood count - price of the test

Blood count tests can be performed free of charge within the framework of the National Health Fund on the basis of a referral from a general practitioner, primary care physician and any specialist.

In the case of private morphology, the cost of the tests depends on the specific laboratory that will analyse the sample. The average price of a basic morphology is between 8 and 14 PLN, while an extended morphology costs between 12 and 20 PLN.

Bibliography:

1. TELEGŁÓW, Aneta. Haematological diagnostics - basic examination: blood morphology. In: A. Teległów (ed.), Laboratory and imaging diagnostics for physiotherapy and cosmetology, AWF im. B. Czech in Kraków, 2020, p. 212-221.
2. FRYNAS-MARKWAT, Aleksandra et PAPIEŻ, Magdalena. Peripheral blood microscopic smear as an essential tool for the primary care physician. In : Forum of Family Medicine. 2024. p. 201-205.
3. ICHIPI-IFUKOR, Patrick Chukwuyenum, JACOBS, Juliet, ICHIPI-IFUKOR, Rita Ngozi, et al. Changes in haematological indices in normal pregnancy. Physiology Journal, 2013, vol. 2013.
4. MATYSIAK, Michal. Anaemias-an ongoing problem in maternal and child care. Family Medicine & Primary Care Review, 2014, vol. 2, p. 185-188.