Hyperkalemia diagnostic study of choice: Difference between revisions
Created page with "__NOTOC__ {{Hyperkalemia }} {{CMG}}; {{AE}} == Overview == == Diagnostic Study of Choice == === Study of choice === [Name of the investigation] is the gold standard test..." |
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=== Study of choice === | === Study of choice === | ||
[ | [Serum potassium] is the gold standard test for the diagnosis of [hyperkalemia]. | ||
There are two methods to determine serum potassium : | |||
* Flame emission spectrophotometry | |||
* Ion-specific electrode (ISE) potentiometry | |||
* | ISE potentiometry has two different subtypes: Direct (undiluted) and indirect (diluted). | ||
'''Direct ISE''' measures plasma potassium directly from a whole-blood sample and it's not associated with either pseudohyperkalemia. | |||
FES or indirect ISE requires sample dilution before assay and both are associated with pseudohyperkalemia. | |||
=== Pseudohyperkalemia === | |||
Pseudohyperkalemia is defined when serum potassium concentration exceeds that of plasma without any symptoms of hyperkalemia.It usually occurs when potassium moves out of cells during blood specimen collection or during centrifugation of the sample.Other causes are thrombocytosis,leukocytosis and erythrocytosis.To rule out pseudohyperkalemia we need to do the following | |||
<nowiki>*</nowiki>Repeat the blood sample | |||
<nowiki>*</nowiki>Complete blood count to rule out thrombocytosis,erythrocytosis and leukocytosis | |||
<nowiki>*</nowiki>Measurement of plasma potassium and whole blood potassium | |||
* | |||
< | |||
===== Diagnostic results ===== | ===== Diagnostic results ===== | ||
The | The finding on performing the diagnostic test that confirms hyperkalemia | ||
<nowiki>*</nowiki>Serum Potassium level more than 5.1 meq/L. | |||
===== Sequence of Diagnostic Studies ===== | ===== Sequence of Diagnostic Studies ===== | ||
The [ | The [serum potassium] must be performed when: | ||
* The patient presented with | * The patient presented with cardiac arrhythmias,weakness,fatigue and known case of chronic kidney disease as the first step of diagnosis. | ||
The various investigations must be performed in the following order: | The various investigations must be performed in the following order: | ||
* | * Blood pressure(to look for hypoaldosteronism) | ||
* | * Complete blood count | ||
* Renal function tests | |||
* Urine potassium,sodium and osmolality | |||
* Metabolic profile(other electrolytes) | |||
* ECG | |||
* Bicarbonate level | |||
* Serum glucose | |||
* Serum Calcium | |||
Depending on the history and results of the above mentioned tests,other tests that can be performed for evaluating the cause of hyperkalemia. | |||
* Digoxin level - If the patient is on a digitalis medication | |||
* Arterial or venous blood gas | |||
* Urinalysis | |||
* Serum cortisol and aldosterone levels | |||
* Serum uric acid and phosphorus assays | |||
* Serum creatinine phosphokinase (CPK) measurements | |||
* Urine myoglobin test | |||
=== Name of Diagnostic Criteria === | === Name of Diagnostic Criteria === | ||
==References== | ==References== |
Revision as of 23:54, 5 July 2018
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
Overview
Diagnostic Study of Choice
Study of choice
[Serum potassium] is the gold standard test for the diagnosis of [hyperkalemia].
There are two methods to determine serum potassium :
- Flame emission spectrophotometry
- Ion-specific electrode (ISE) potentiometry
ISE potentiometry has two different subtypes: Direct (undiluted) and indirect (diluted).
Direct ISE measures plasma potassium directly from a whole-blood sample and it's not associated with either pseudohyperkalemia.
FES or indirect ISE requires sample dilution before assay and both are associated with pseudohyperkalemia.
Pseudohyperkalemia
Pseudohyperkalemia is defined when serum potassium concentration exceeds that of plasma without any symptoms of hyperkalemia.It usually occurs when potassium moves out of cells during blood specimen collection or during centrifugation of the sample.Other causes are thrombocytosis,leukocytosis and erythrocytosis.To rule out pseudohyperkalemia we need to do the following
*Repeat the blood sample
*Complete blood count to rule out thrombocytosis,erythrocytosis and leukocytosis
*Measurement of plasma potassium and whole blood potassium
Diagnostic results
The finding on performing the diagnostic test that confirms hyperkalemia
*Serum Potassium level more than 5.1 meq/L.
Sequence of Diagnostic Studies
The [serum potassium] must be performed when:
- The patient presented with cardiac arrhythmias,weakness,fatigue and known case of chronic kidney disease as the first step of diagnosis.
The various investigations must be performed in the following order:
- Blood pressure(to look for hypoaldosteronism)
- Complete blood count
- Renal function tests
- Urine potassium,sodium and osmolality
- Metabolic profile(other electrolytes)
- ECG
- Bicarbonate level
- Serum glucose
- Serum Calcium
Depending on the history and results of the above mentioned tests,other tests that can be performed for evaluating the cause of hyperkalemia.
- Digoxin level - If the patient is on a digitalis medication
- Arterial or venous blood gas
- Urinalysis
- Serum cortisol and aldosterone levels
- Serum uric acid and phosphorus assays
- Serum creatinine phosphokinase (CPK) measurements
- Urine myoglobin test