Please find information by clicking on the links below:

Advice Regarding Result Interpretation:

ALLERGY TESTING - How to diagnose allergy in adults in primary care 

B12 - see HAEMATINICS

BIOTIN- Biotin Interference in Roche-manufactured Immunoassays * Updated Sept 2024*

BNP - Use of natriuretic peptides in the management of suspected heart failure 

CALCIUM

– Guidance for assessment of hypercalcaemia in primary care

– Investigation of Hypocalcaemia in Primary Care 

CALPROTECTIN

- The York faecal calprotectin care pathway for GPs 

 - Faecal calprotectin guidance for patients being managed in secondary care 

CORTISOL - Investigation of Adrenal Insufficiency and Cushing’s Syndrome in Adults

CHLORIDE – Guidance for interpreting chloride results

CREATINE KINASE - Causes of Elevated CK 

CRP - See INFLAMMATORY MARKERS

CUSHINGS SYNDROME - See CORTISOL

DIABETES - see HBA1C

ESR - See INFLAMMATORY MARKERS

ESTRADIOL – See OESTRADIOL

FAECAL CALPROTECTIN - See CALPROTECTIN

FERRITIN (high) - Investigation of elevated ferritin

FERRITIN (low) See HAEMATINICS

FOLATE - See HAEMATINCS

FREE LIGHT CHAINS – Guidance for interpreting free light chain results 

FSH - Menopause investigation and laboratory testing 

HAEMATINICS - Guidance for primary care on interpretation of haematinics (B12, folate and ferritin)

HBA1C (diagnosis of diabetes) – Guidance for when HbA1c is not suitable for diagnosis of diabetes

HBA1C (monitoring of diabetes) – Guidance for when HbA1c is not suitable for monitoring diabetes

HEART FAILURE - See BNP

HYPERKALAEMIA - See POTASSIUM

HYPONATRAEMIA - See SODIUM

HYPOMAGNESAEMIA - See MAGNESIUM

HYPOPHOSPHATAEMIA - See PHOSPHATE

IMMUNOGLOBULINS  - Guidance for investigation of low immunoglobulins 

INFLAMMATORY MARKERS – Guidance for which test to use and when

LIVER BLOOD TESTS / LIVER DISEASE - 

- Liver disease in Primary Care - Investigation of abnormal liver blood test results (adults) *Updated April 25*

- Reference Ranges for Liver Function Tests in Pregnancy 

MAGNESIUM - Guidance for assessment and management of hypomagnesaemia in primary care 

MENOPAUSE - See FSH

METANEPHRINES (Urine) – Investigation of suspected phaeochromocytoma using 24h urine metanephrines 

MYELOMA/MGUS - See PARAPROTEINS

OSMOLALITY (Urine) - Guidance for investigation of polyuria/polydipsia

OESTRADIOL – Interpreting serum oestradiol levels 

PARAPROTEINS - Management of patients with paraprotein 

PHOSPHATE -

Information for Primary Care: Management of Hypophosphataemia  

Renal Tubular Reabsorption of Phosphate 

POTASSIUM -

- Investigating and management of hyperkalaemia (high potassium) in primary care (adults)

- Investigating and management of hypokalaemia (low potassium) in primary care (adults)

- Top tips for avoiding haemolysis

- Hyperkalaemia due to DELAYED CENTRIFUGATION 

- To enquire about obtaining a centrifuge for your surgery, please contact Carl Burkinshaw, Biochemistry Operational Manager (York and Scarborough): 01723 342028, carl.burkinshaw@york.nhs.uk

POLYURIA- see OSMOLALITY (Urine)

PROLACTIN - Investigation of hyperprolactinaemia 

PV - See INFLAMMATORY MARKERS

Renal Tubular Reabsorption of Phosphate - See PHOSPHATE

SODIUM - Investigation and management of hyponatraemia in primary care (Adults) 

THERAPEUTIC DRUGS - Sampling requirements for commonly requested therapeutic drugs

THYROID FUNCTION TESTS - Guidance for requesting and interpreting thyroid function tests (TFTs)

TRACE ELEMENTS (ZINC, SELENIUM, COPPER) - A guide to requesting trace elements for adults in primary care *Updated April 25*

TROPONIN - Troponin testing in primary care

---

Web Page 26 Last Updated: 30/06/2025