Specimen requirement

Plasma

Fluid

Adult patient:

 Heparin gel tube

Minimum blood volume: 5 mL

Plain bottle

Minimum volume: 10 mL

Paediatric patient:

Paediatric heparin tube

Number of vials: 1

Minimum blood volume: 1.3 mL

Authorisation code required

No

No

24 Hr available service

Yes

(Call extension: 3353 for express result)

No

Precaution

Avoid excessive use of tourniquet for sample collection.

Posture influences levels.

Method

Spectrophotometry

Reference interval

Plasma:

(Source: from local population study in 2008)

Pleural fluid for Light’s discrimination criteria:

Pleural fluid is an exudate if one or more of the following criteria are met:

1. fluid TP / plasma TP > 0.5
2. fluid LDH / plasma LDH > 0.6
3. fluid LDH concentration > 2/3 of the upper limit of normal plasma range

(Source: Hooper C et al. Thorax 2015; 65 (Suppl 2): ii4 - ii17)

Clinical indication

Used in conjunction with albumin to calculate globulin.

Diagnosis and monitoring of hyper- and hypo-gammaglobulinaemia, protein losing states and malnutrition

Result interpretation

Depends on the levels of albumin and immunoglobulins, which are the only proteins present in serum in sufficient concentration to significantly alter total protein levels.

Increased total protein:

• Chronic infections

• Rheumatoid arthritis, lupus erythematosus and multiple myeloma

• After excessive venous stasis during blood collection

• Dehydration.

Decreased total protein:

• Agammaglobulinemia (inherited inability to synthesise gamma globulins which is very rare)

• Decreased albumin

The total protein concentration is by 0.4 to 0.8 g/L lower when the sample is collected from a patient situated in the recumbent position rather than upright.

Measurement of uncertainty

See table.

Frequency of measurement

Daily