Why do you collect 4 tubes when performing lumbar puncture?
Hematology analysis is typically performed on the last tube collected (3 or 4) to assure that any peripheral blood that may have contaminated the sample during the lumbar puncture has cleared.
What are the 4 tubes for lumbar puncture?
The classic approach is to send the 4 CSF tubes for the following studies:
- Tube 1 – Cell count and differential.
- Tube 2 – Glucose and protein levels.
- Tube 3 – Gram stain, culture and sensitivity (C&S)
- Tube 4 – Cell count and differential.
How many tubes do you need for a lumbar puncture?
The needle doesn’t touch the nerves of your spinal cord. Your doctor will collect between 5 to 20 ml of cerebrospinal fluid in 2 to 4 tubes. Figure 1. A needle is placed in the subarachnoid space at the level of the 3rd and 4th lumbar vertebra to collect a sample of cerebrospinal fluid.
How many tubes are collected for CSF?
Cerebrospinal fluid specimens
| Default tube numbers for type of testing | ||
|---|---|---|
| Number of tubes submitted | 4 tubes | 2 tubes* |
| Chemistry (glucose, lactate, LDH, protein, etc) | 3 | 1 |
| Cultures (bacterial, viral) | 2 | 2 |
| Cell Count (appearance, color, RBC, nucleated cells) | 1 and 4 | 2 |
What level should a lumbar puncture be?
A diagnostic Lumbar Puncture should be performed at the L3/4 interspinal space, marked ‘x’. The approximate distance from the skin to the epidural space is 45-55mm and the dura mater may be up to 7mm beyond that depth.
Which is the best way to position a patient for lumbar puncture?
Positioning — An LP can be performed with the patient in the lateral recumbent or prone positions or sitting upright. The lateral recumbent or prone positions are preferred over the upright position because they allow more accurate measurement of the opening pressure.
When 4 tubes are collected for cerebrospinal fluid testing what is the last tube used for?
Tube 3 can be used for microbiology testing. Hematology analysis is typically performed on the last tube collected (3 or 4) to ensure that any peripheral blood that may have contaminated the sample during the lumbar puncture has cleared.
Which tube is used for bacteriologic studies in CSF samples?
After drawing the CSF sample, do the following with the tubes: Tube 1 – Send to the chemistry laboratory for glucose and protein. Tube 2 – Send to the hematology laboratory for a cell count with differential. Tube 3 – Send to the microbiology and immunology laboratory.