View source for 2. Patient preparation before sampling. Proper method to carry out blood (venous, capillary) and urine collection. Type of tubes.

== Patient preparation ==

* Preanalysis
** Clinical question
** Request for analyses
** Patient sampling
** Transit to lab
* Analysis
* Postanalysis
** Collection
** Interpretation
** Reporting
** Answer
{{#lst:Urine analysis|clinical biochemistry}}
== Sources of errors ==
Preanalytical errors are errors which occur in the preanalytical phase, including ordering the test, patient identification, patient preparation ahead of analysis, sample collection, and sample transportation to the lab. Preanalytical errors account for 80% of all errors of laboratory investigations.

Preanalytical factors:

* Preparation of patient
** Identification
** Diet
*** Fasting affects glucose, triglycerides
** Drugs
** Smoking
** Pregnancy
** Exercise
*** Epinephrine, cortisol increase
** Dehydration
** Infection
*** Iron parameters wrong
*** TSH, thyroid hormones wrong
* Sample taking
** Posture
*** Increased in standing position: RBC, WBC, Hb, HTC, …
** Time of sample taking
*** Cortisol highest in morning
*** TSH highest in evening
** Strangulation
*** Max 1 min!
** Simultaneous infusions
** Identification of the sample
** Patting the vein
** Shaking the tubes too much
** Correct tube
** Correct order
** Correct vessel
** Correct filling of tube
* Sample preparation
** Haemolysis
*** Increased LDH, K+
*** Decreased RBC
*** Interferes with photometry, haemostasis
** Clotting
** Lipaemia
** Centrifugation
** The elapsed time from sample taking
*** Blood gas: max 30 min
** Temperature
*** Usually room temperature
*** Store on ice: ACTH, renin, aldosterone
** Sunlight
** Labelling
** Delivery
* Errors in case of urine collection:
** First morning urine
*** Unsanitary
*** Clean container
*** Duration of sample storage
** 24-hour urine
*** Many possible errors

== Types of tubes ==
{| class="wikitable"
!'''Order'''
!'''Tube'''
!'''Additive'''
!'''Colour'''
!'''Blood product'''
!'''Use'''
|-
|0.
|Blood culture
|–
|–
|
|Culture
|-
|1.
|Haemostasis tube
|Sodium citrate
|Light blue
|Plasma
|Coagulation studies
|-
|'''2.'''
|'''Sedimentation tube'''
|'''Sodium citrate'''
|'''Black'''
|'''Plasma'''
|'''ESR'''
|-
|3.
|Plain tube
|Nothing
|Red
|Serum
|Biochemistry, immunology, serology
|-
|'''4.'''
|'''Serum tube'''
|'''Gel + clot activator'''
|'''Yellow'''
|'''Serum'''
|'''Biochemistry, immunology, serology'''
|-
|5.
|Heparin tube
|Lithium heparin
|Green
|Plasma
|Blood gas values
|-
|6.
|EDTA tube
|EDTA
|Purple
|Plasma
|<abbr>CBC</abbr>
|-
|'''7.'''
|'''Glycolysis inhibitor'''
|'''Fluoride, oxalate'''
|'''Grey'''
|'''Plasma'''
|'''Glucose, lactate'''
|}
[[Category:Clinical Biochemistry (POTE course)]]