hand of a lab technician holding blood tube test and background a rack of color...

Source: Shutterstock/angellodeco

Article • Hematology

Recommendations on venous blood sampling

Pre-analytics, in particular venous blood sampling has a major impact on the quality of laboratory diagnostic results. An estimated 75 percent of all "lab errors" are caused by errors during pre-analytics. Thus, the German Medical Association’s national guideline on laboratory diagnostics includes detailed guidance on pre-analytics, in particular venous blood sampling.

In their current publication, Joint EFLM-COLABIOCLI Recommendation for venous blood sampling, the Working Group on Pre-analytics (WG-PRE and WG-PRE-LATAM) of the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) and the Latin America Confederation of Clinical Biochemistry (COLABIOCLI) present data on venous blood sampling and individually assess their impact on errors in the results. Twenty discrete steps are described and recommendations are presented in six grades, from 1A (strong recommendation with high quality evidence) to 2C (weak recommendation with low quality evidence – see table).


Initial pre-sampling communication with the patient is considered an important recommendation with low quality evidence (grade 1C). Correct patient identification is particularly important. Many laboratory parameters, e.g. proteins, can be strongly affected by the patient’s position during sampling. Therefore, the patient should ideally not change his/her position within 15 minutes prior to blood sampling. While this usually is not an issue with hospitalized, bedridden patients, for outpatient sampling, which is mostly done with the patient in a sitting position, this might be important. All blood tests should be drawn in the morning (between 7 and 9 am) in a fasting state, 12 hours after the last meal. Moreover, consumption of alcohol and caffeine-containing beverages, cigarette smoking and chewing gum within 24 hours prior to blood sampling can significantly affect the parameters to be analysed. These are strong recommendations with moderate quality evidence. Specific issues, such as drug monitoring, follow separate guidelines.

All supplies, devices and equipment required for blood sampling should be available, their presence being verified by the person performing the sampling. This is a grade 2C recommen dation – weak recommendation, low quality evidence. Correct labelling of the tubes, however, is considered a 1C recommendation – strong recommendation, low quality evidence.


blood test tubes
Source: Shutterstock/Africa Studio

The same grade, 1C, is accorded to the wearing of gloves during the actual sampling procedure. Applying a tourniquet is a strong recommendation with high quality evidence (1A). Selection of the adequate venepuncture site requires precise anatomical knowledge on the course of the arm veins. The authors consider this a strong recommendation with moderate quality evidence (1B). Equally important, according to the authors, is thorough cleansing of the venepuncture site with 70 percent ethyl alcohol or any other appropriate disinfectant prior to sampling. 

Alcohol drying times and handling of the disinfected site are described in detail. The next steps, puncturing the vein either with the needle or a butterfly, drawing the blood into the first tube and releasing the tourniquet are strong recommendations with high quality evidence (1A). The authors, moreover, consider the order of draw of utmost importance: blood culture tube, citrate tube, plain tube or tube with clot activator, heparin tube, EDTA tube, glycolysis inhibitor tube (NaF or comparable) and other tubes. Another strong recommendation is inversion, 5 to 10 times, of the correctly filled sample tubes. Gentle removal of the needle and correct disposal in adequate containers is a strong recommendation with high quality evidence (1A).

Subsequent treatment of the wound and asking the patient to apply pressure on the puncture site are strong recommendations with low quality evidence (1C).The tubes are inverted four more times, the gloves are removed and discarded. Correct removal of the gloves is considered a strong recommendation with high quality evidence.

Post sampling

After sampling, the patient should be advised to rest for about five minutes or he/she should be monitored by the person who took the sample until the bleeding has stopped. Communication with the patient that concludes the procedure is, according to the authors, a strong recommendation with moderate quality evidence. In a final section the authors discuss the implementation of the guidelines. Here, national laws and regulations which might pose an implementation barrier or challenge have to be considered. In order to successfully implement these guidelines on correct and error-free venous blood sampling a number of measures need to be taken. Staff has to be trained and refresher training has to be offered in regular intervals. Certification and regular recertification of the training as well as the actual performance of the procedure is useful. In the meantime audits are a suitable instrument to ensure long-term quality.

For hospitals, the authors recommend an implementation team with a team leader who is familiar with all national laws, regulations and recommendations and applies them resp. complies with them in the course of the implementation of the „Recommendations on venous blood sampling“.

Venous blood sampling — the sequence of steps

Strength of evidence
1. Identify the patient
2. Verify patient is fasting and properly prepared
3. Obtain supplies required for blood collection
4. Label/identify tubes
5. Put on gloves
6. Apply tourniquet
7. Select venipuncture site
8. Clean sampling site
9. Puncture the vein
10. Draw first tube
11. Release the tourniquet
12. Gently invert the tube once (one full inversion)
13. Draw additional tubes following order of draw
14. Remove needle from the vein and activate safety feature
15. Dispose of the needle
16. Bandage the puncture site
17. Tell the patient to apply a gentle pressure for 5-10 min and not to bend the arm
18. Invert all tubes 4 times
19. Remove gloves
20. Advise patient to rest for 5 min and ensure bleeding has stopped before leaving the site of venous blood collection


1A: strong recommendation, high quality evidence (benefits clearly outweigh risk and burdens or vice versa)

1B: strong recommendation, moderate quality evidence (benefits clearly outweigh risk and burdens or vice versa)

1C: strong recommendation, low quality evidence (benefits appear to outweigh risk and burdens or vice versa)

2A: weak recommendation, high quality evidence (benefits closely balanced with risks and burdens)

2B: weak recommendation, moderate quality evidence (benefits closely balanced with risk and burdens, some uncertainties in the estimates of benefits, risk and/or burdens)

2C: weak recommendation, low quality evidence (uncertainty in the estimates of benefits, risks and/or burdens; benefits may be closely balanced with risk and burdens)

Source: https://www.uptodate.com/home/grading-guide#GradingRecommendations

portrait of norbert gässler
Prof Dr Dr Norbert Gässler is Director of the Centre of Laboratory Diagnostics at St. Bernward Hospital in Hildesheim

The original publication, further relevant publications and material to support implementation (poster, presentation, video) can be found on the Working Group‘s resource/educational material page.


Prof Dr Dr Norbert Gässler is Director of the Centre of Laboratory Diagnostics at St. Bernward Hospital in Hildesheim, Germany, and POCT specialist. He is also an EFLM-certified European Specialist in Laboratory Medicine. Professor Gässler is a member of many professional associations, inter alia the American Association for Clinical Chemistry (AACC), the Professional Association of Scientists in Laboratory Diagnostics (Berufsvereinigung der Naturwissenschaftler in der Labordiagnostik – BNLD) and the German Society of Clinical Chemistry (Deutsche Gesellschaft für Klinische Chemie und Laboratoriumsmedizin – DGKL). He moreover authored and co-authored a number of clinical studies on POCT.


Related articles


Sponsored • Hematology

Sysmex Corporation: The global leader in hematology

Founded in 1968, The Sysmex Corporation has challenged its way past far larger companies to become one of the leading healthcare companies around the world. How? By focusing constantly on one…


News • Troponin assessment

Blood test aids emergency diagnosis of heart conditions

A high sensitivity blood test can improve diagnosis for one in five patients who have a heart muscle injury, according to new research.


Sponsored • Earlier disease prediction and identification

The potential of AI in routine blood testing

It’s widely known that more than 70% of today’s medical decisions involve the results of laboratory tests, but the insights clinicians derive from these tests today may only be scratching the…

Related products

Subscribe to Newsletter