Serum vitamin B12
Name vitamin_b12_gprd
Chapter Diseases of the blood/Haematinics
Serum vitamin B12 in pmol/L.

Vitamin B12 may be recorded in the GPRD test table in units ng/L (pg/mL) or pmol/L. All vitamin B12 values are converted to pmol/L as it is the SI unit.

Values with units ug/L and ug/mL have the same distribution as those with units stated as ng/L, so it is assumed that the units are incorrect, and they are treated as if the units are ng/L.

Values in ng/L are multiplied by 0.738 to convert them to pmol/L. Values of 0 or >= 10000 are considered to be errors.
Data Type Continuous
Data sources GPRD
Dictionaries Read
Repeated Yes
Units pmol/L
Range (min/max) 0-10000
Valid event date range 01/01/1900 - 25/03/2010
Agreed 27 Jun 2013 (Revision 1)
IF Read code IN vitamin_b12_gprd codelist

AND enttype = 157 THEN (

    IF data3 [units] IN (105 [ng/L], 116 [pg/mL], 156 [ug/L], 99 [ug/mL]) 

    AND data2 [value] < 10000 AND data2 > 0 THEN vitamin_b12_gprd = data2 * 0.738

    ELSE IF data3 [units] IN (142 [umol/L], 120 [pmol/L]) 

    AND data2 [value] < 10000 AND data2 > 0 THEN vitamin_b12_gprd = data2

    ELSE vitamin_b12_gprd = Missing

Codelist version1
Codelist authorsAnoop Shah
Creation date27 Jun 2013
Category (code) Read code Read term CPRD Medcode
(1) 42T..00 Serum vitamin B12 7926
(1) 42T1.00 Serum vitamin B12 normal 13723
(1) 42T2.00 Serum vitamin B12 low 4647
(1) 42T3.00 Serum vit B12 borderline 18873
(1) 42TZ.00 Serum vitamin B12 NOS 18648
(1) 44Lc.00 Vitamin B12 level 18526
(1) 44Le.00 Plasma vitamin B12 level 18570
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